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1
McGinty, Peter. "Preparation of the New Zealand earthquake catalogue for a probabilistic seismic hazard analysis." Bulletin of the New Zealand Society for Earthquake Engineering 34, no. 1 (March 31, 2001): 60–67. http://dx.doi.org/10.5459/bnzsee.34.1.60-67.
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The seismic hazard from ground motions during a New Zealand earthquake is variable, and is dependent on the different tectonic processes that occur throughout the country. A modem probabilistic seismic hazard analysis (PSHA) combines various data sets to take account of these different environmental effects and rates of occurrence. Earthquake catalogue data can be used to give the rate of background or distributed seismicity in historical times, while paleoseismic data can be used to constrain the return time of large earthquakes. The background seismicity is assumed to occur as a time-independent Poisson process. To apply this assumption to a new PSHA of New Zealand, completeness levels for the New Zealand earthquake catalogue were established, and aftershocks or clusters of events that occurred close together in both space and time were removed from the catalogue. The level of hazard in a region can be depth-dependent, that is the risk of a large earthquake may come from a shallow crustal event or a deep subduction zone event, both having the same epicentral location but resulting in different levels of damage. The New Zealand earthquake catalogue has too many events that have been assigned restricted depths to be ignored. These events have been statistically redistributed into shallow crustal zones or deep subducted slab zones based on the last eleven years of catalogue data, when improvements in technology have reduced the number of restricted events.
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Van Dissen, R. J., J. J. Taber, W. R. Stephenson, S. Sritheran, S. A. L. Read, G. H. McVerry, G. D. Dellow, and P. R. Barker. "Earthquake ground shaking hazard assessment for the Lower Hutt and Porirua areas, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 25, no. 4 (December 31, 1992): 286–302. http://dx.doi.org/10.5459/bnzsee.25.4.286-302.
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Geographic variations in strong ground shaking expected during damaging earthquakes impacting on the Lower Hutt and Porirua areas are identified and quantified. Four ground shaking hazard zones have been mapped in the Lower Hutt area, and three in Porirua, based on geological, weak motion, and strong motion inputs. These hazard zones are graded from 1 to 5. In general, Zone 5 areas are subject to the greatest hazard, and Zone 1 areas the least. In Lower Hutt, zones 3 and 4 are not differentiated and are referred to as Zone 3-4. The five-fold classification is used to indicate the range of relative response.
Zone 1 areas are underlain by bedrock. Zone 2 areas are typically underlain by compact alluvial and fan gravel. Zone 3-4 is underlain, to a depth of 20 m, by interfingered layers of flexible (soft) sediment (fine sand, silt, clay, peat), and compact gravel and sand. Zone 5 is directly underlain by more than 10 m of flexible sediment with shear wave velocities in the order of 200 m/s or less.
The response of each zone is assessed for two earthquake scenarios. Scenario 1 is for a moderate to large, shallow, distant earthquake that results in regional Modified Mercalli intensity V-VI shaking on bedrock. Scenario 2 is for a large, local, but rarer, Wellington fault earthquake. The response characterisation for each zone comprises: expected Modified Mercalli intensity; peak horizontal ground acceleration; duration of strong shaking; and amplification of ground motion with respect to bedrock, expressed as a Fourier spectral ratio, including the frequency range over which the most pronounced amplification occurs. In brief, high to very high ground motion amplifications are expected in Zone 5, relative to Zone 1, during a scenario 1 earthquake. Peak Fourier spectral ratios of 10-20 are expected in Zone 5, relative to Zone 1, and a difference of up to three, possibly four, MM intensity units is expected between the two zones. During a scenario 2 event, it is anticipated that the level of shaking throughout the Lower Hutt and Porirua region will increase markedly, relative to scenario 1, and the average difference in shaking between each zone will decrease.
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Dowrick, D. J., D. A. Rhoades, and P. N. Davenport. "Damage ratios for domestic property in the magnitude 7.2 1968 Inangahua, New Zealand, earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 34, no. 3 (September 30, 2001): 191–213. http://dx.doi.org/10.5459/bnzsee.34.3.191-213.
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An analysis of damage costs to domestic property in the Mw 7.2 Inangahua, New Zealand, earthquake of 23 May 1968 (U.T.) has allowed the evaluation of the vulnerability of domestic property for six intensity zones, from MM5 - MM10 inclusive. For no other earthquake worldwide has the vulnerability of any class of property been examined in so many intensity zones, and the effect of brittle chimneys on damage levels has been fully evaluated for the first time. The relative vulnerability of one and two storey houses has also been evaluated. The costs of damage were derived from about 8,000 insurance claims to the Earthquake and War Damage Commission. Damage ratios were evaluated for houses and their contents as functions of Modified Mercalli intensity. The indicators of vulnerability that were determined were the statistical distributions and mean values of damage ratios and the percentage of property items damaged for the six intensity zones. Comparisons have also been made with results from studies of other earthquakes.
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Filippova, Olga, Michael Rehm, and Chris Dibble. "Office market response to earthquake risk in New Zealand." Journal of Property Investment & Finance 35, no. 1 (February 6, 2017): 44–57. http://dx.doi.org/10.1108/jpif-05-2016-0026.
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Purpose With the marked increase in the awareness of earthquake risks following the Canterbury earthquakes, the purpose of this paper is to assess if the reassessment of risk has influenced rents for office accommodation in commercial buildings. Two contrasting office markets are examined: New Zealand’s largest market within a high-risk earthquake zone – Wellington, and the country’s largest market within a low-risk zone – Auckland. Design/methodology/approach A sample of 252 leasing transactions were collected from a proprietary database of Colliers International, one of the largest commercial brokerage firms in New Zealand. Hedonic pricing models were developed to isolate the effects of building seismic strength on office rents. Findings Wellington office market rents tend to increase with higher earthquake strength (New Building Standard) ratings, all other factors held equal. In contrast, rents in Auckland, a low-risk earthquake area, do not exhibit such price effects. Practical implications The study provides estimates of the economic value associated with seismic retrofits which are vital for building owners’ decision making who must weigh retrofit costs against the economic benefits of doing so. Originality/value This study provides the first empirical analysis of office rents in New Zealand and the first quantitative analysis, internationally, of the impact of earthquake risk on commercial rents.
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Halliday, Jessica. "FESTA Festival of Transitional Architecture in Christchurch, New Zealand." Journal of Public Space 2, no. 3 (December 9, 2017): 177. http://dx.doi.org/10.5204/jps.v2i3.126.
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<p>In 2012 <a href="http://www.festa.org.nz">FESTA</a> emerged in Christchurch, New Zealand as a collective response to the extraordinary circumstances of a natural disaster. As a place-based (and now biennial) weekend-long festival of architecture and urbanism it continues to seek and find relevance to that place, its people, and to all involved in the event (participants, audience, funders and supporters) as the extraordinary fades into a more ordered and ordinary existence.<br />On 22 February 2011, a large earthquake hit the city of Christchurch, New Zealand. It was the second largest, and most destructive, of a series of over 11,000 earthquakes recorded in the region over a 2-year period from September 2010. 185 people died as a result of the February quake and over 75% of the built fabric of the central city was demolished. Christchurch’s central city was cordoned off from the public and put under army control, portions of it for over two years. A new government agency was established to direct the city’s recovery. It commissioned and backed a new spatial plan for the central city (‘<a href="http://architecturenow.co.nz/articles/the-final-blueprint-for-a-new-christchurch/">The Blueprint’</a>), designed to retain existing land values and incentivise new and current investment as well as renew public spaces and amenities. Land damage caused whole suburban areas to be deemed unrepairable and these neighbourhoods were ‘<a href="https://teara.govt.nz/en/zoomify/46379/eastern-suburbs-red-zone">red zoned’</a> and purchased by the central government. Over 4 years, 8000 homes in the suburban red zones were demolished. Drastic change and uncertainty touched most aspects of Christchurch people’s lives in the years following the earthquake.</p>
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Stirling, Mark, Jarg Pettinga, Kelvin Berryman, and Mark Yetton. "Probabilistic seismic hazard assessment of the Canterbury region, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 34, no. 4 (December 31, 2001): 318–34. http://dx.doi.org/10.5459/bnzsee.34.4.318-334.
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We present the main results of a probabilistic seismic hazard assessment of the Canterbury region recently completed for Environment Canterbury (formerly Canterbury Regional Council). We use the distribution of active faults and the historical record of earthquakes to estimate the levels of earthquake shaking (peak ground acceleration and response spectral accelerations) that can be expected across the Canterbury region with return periods of 150, 475 and 1000 years. The strongest shaking (e.g. 475 year peak ground accelerations of 0.7g or more) can be expected in the west and north to northwest of the Canterbury region, where the greatest concentrations of known active faults and historical seismicity are located. Site-specific analyses of eight towns and cities selected by Environment Canterbury show that Arthur's Pass and Kaikoura are located within these zones of high hazard. In contrast, the centres studied in the Canterbury Plains (Rangiora, Kaiapoi, Christchurch, Ashburton, Temuka and Timaru) are generally located away from the zones of highest hazard. The study represents the first application of recently-developed methods in probabilistic seismic hazard at a regional scale in New Zealand.
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Van Houtte, Chris. "Performance of response spectral models against New Zealand data." Bulletin of the New Zealand Society for Earthquake Engineering 50, no. 1 (March 31, 2017): 21–38. http://dx.doi.org/10.5459/bnzsee.50.1.21-38.
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An important component of seismic hazard assessment is the prediction of the potential ground motion generated by a given earthquake source. In New Zealand seismic hazard studies, it is commonplace for analysts to only adopt one or two models for predicting the ground motion, which does not capture the epistemic uncertainty associated with the prediction. This study analyses a suite of New Zealand and international models against the New Zealand Strong Motion Database, both for New Zealand crustal earthquakes and earthquakes in the Hikurangi subduction zone. It is found that, in general, the foreign models perform similarly or better with respect to recorded New Zealand data than the models specifically derived for New Zealand application. Justification is given for using global models in future seismic hazard analysis in New Zealand. Although this article does not provide definitive model weights for future hazard analysis, some recommendations and guidance are provided.
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Hutchinson, G., J. Wilson, L. Pham, I. Billings, R. Jury, and A. King. "Developing a common Australasian Earthquake Loading Standard." Bulletin of the New Zealand Society for Earthquake Engineering 28, no. 4 (December 31, 1995): 288–93. http://dx.doi.org/10.5459/bnzsee.28.4.288-293.
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The development of a common Earthquake Loading Standard for Australia and New Zealand which has the potential for most countries in SE Asia is discussed in this paper. An historical perspective of earthquake loading standards in the two countries is introduced for background. In addition, two internationally recognised standards, Uniform Building Code (UBC) and Eurocode 8, covering earthquake loadings for areas of both low and high seismicity are presented. A seismic zoning scheme similar to the UBC approach is tentatively suggested for describing the seismic hazard of Australia and New Zealand. It is suggested that the requirements for design and detailing could vary from nominal tying together to capacity design procedures for the lowest and highest seismic zones respectively.
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McVerry, Graeme H., John X. Zhao, Norman A. Abrahamson, and Paul G. Somerville. "New Zealand acceleration response spectrum attenuation relations for crustal and subduction zone earthquakes." Bulletin of the New Zealand Society for Earthquake Engineering 39, no. 1 (March 31, 2006): 1–58. http://dx.doi.org/10.5459/bnzsee.39.1.1-58.
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Attenuation relations are presented for peak ground accelerations (pga) and 5% damped acceleration response spectra in New Zealand earthquakes. Expressions are given for both the larger and the geometric mean of two randomly-oriented but orthogonal horizontal components of motion. The relations take account of the different tectonic types of earthquakes in New Zealand, i.e., crustal, subduction interface and dipping slab, and of the different source mechanisms for crustal earthquakes. They also model the faster attenuation of high-frequency earthquake ground motions in the volcanic region than elsewhere. Both the crustal and subduction zone attenuation expressions have been obtained by modifying overseas models for each of these tectonic environments to better match New Zealand data, and to cover site classes that relate directly to those used for seismic design in New Zealand codes.
The study used all available data from the New Zealand strong-motion earthquake accelerograph network up to the end of 1995 that satisfied various selection criteria, supplemented by selected data from digital seismographs. The seismographs provided additional records from rock sites, and of motions involving propagation paths through the volcanic region, classes of data that are sparse in records produced by the accelerograph network. The New Zealand strong-motion dataset lacks records in the nearsource region, with only one record from a distance of less than 10 km from the source, and at magnitudes greater than Mw 7.23. The New Zealand data used in the regression analyses ranged in source distance from 6 km to 400 km (the selected cutoff) and in moment magnitude from 5.08 to 7.23 for pga, with the maximum magnitude reducing to 7.09 for response spectra data. The required near-source constraint has been obtained by supplementing the New Zealand dataset with overseas peak ground acceleration data (but not response spectra) recorded at distances less than 10 km from the source. Further near-source constraints were obtained from the overseas attenuation models, in terms of relationships that had to be maintained between various coefficients that control the estimated motions at short distances. Other coefficients were fitted from regression analyses to better match the New Zealand data.
The need for different treatment of crustal and subduction zone earthquakes is most apparent when the effects or source mechanism are taken into account. For crustal earthquakes, reverse mechanism events produce the strongest motions, followed by strike-slip and normal events. For subduction zone events, the reverse mechanism interface events have the lowest motions, at least in the period range up to about ls, while the slab events, usually with normal mechanisms, are generally strongest.
The attenuation relations presented in this paper have been used in many hazard studies in New Zealand over the last five years. In particular, they have been used in the derivation of the elastic site spectra in the new Standard for earthquake loads in New Zealand, NZS 1170.5:2004.
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Stirling, Mark, Robert Langridge, Rafael Benites, and Hector Aleman. "The magnitude 8.3 June 23 2001 southern Peru earthquake and tsunami." Bulletin of the New Zealand Society for Earthquake Engineering 36, no. 3 (September 30, 2003): 189–207. http://dx.doi.org/10.5459/bnzsee.36.3.189-207.
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We present a precis of our reconnaissance trip to the area of the magnitude 8.3 June 23 2001 southern Peru earthquake and tsunami. The trip was undertaken because of the relevance of the event to hazard assessment in New Zealand. It is the best example in nearly 40 years of the maximum-size earthquake that might occur on the Hikurangi subduction zone, an event that is absent from the historical record of New Zealand (since 1840) and therefore of unknown potential in terms of hazard. Despite the great magnitude of this subduction interface earthquake, it produced only "moderately strong" levels of earthquake shaking (peak ground acceleration of 0.3g on alluvium from the one strong motion accelerograph in the earthquake area, and Modified Mercalli Intensity 8 in the epicentral area), and relatively minor ground damage (liquefaction and landslides). It did however produce a large and devastating tsunami. Our comparison of the one accelerograph record and attenuation curves for subduction interface earthquakes shows that the strength of shaking was typical for subduction interface earthquakes. If we apply our observations to New Zealand, they imply that a Hikurangi subduction interface earthquake may be less damaging to built-up areas in the southeastern part of the North Island (e.g. Wellington and Napier/Hastings) than earthquakes on major active faults in the shallow crust. However, the lateral extent of the strongest shaking in a subduction earthquake (300 km for the southern Peru event) and the associated tsunami generation will make the earthquake very significant in the national context.
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Cowan, Hugh, Graeme Beattie, Katherine Hill, Noel Evans, Craig McGhie, Gary Gibson, Graeme Lawrance, et al. "The M8.8 Chile earthquake, 27 February 2010." Bulletin of the New Zealand Society for Earthquake Engineering 44, no. 3 (September 30, 2011): 123–66. http://dx.doi.org/10.5459/bnzsee.44.3.123-166.
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The largest earthquake of 2010 by magnitude (MW8.8), and the subject of this article, struck south-central Chile in the early hours of 27 February 2010. The earthquake was a “mega-thrust” event, involving the rupture of a section of the Nazca-South American plate boundary, where the Nazca plate dips at a shallow angle beneath the Pacific margin of South America.
Understanding this event and its effects, including tsunami is of particular significance to urban centres that share close proximity to “subduction zones”. These include Seattle, Vancouver, Tokyo and Wellington, together with smaller New Zealand towns of the eastern North Island and upper South Island. The tectonic setting of south-central Chile has similarities to the East Coast of the North Island, and the modern built environment of Chile shares attributes with New Zealand. However, New Zealand has not experienced a large subduction earthquake in the North Island region in at least 200 years, so an understanding of the Chile event and its impact is important for bench-marking of local practices and building resilience.
This report summarises the observations of the NZSEE/EQC teams, supplemented by media updates on the Chilean reconstruction experience one year after the earthquake.
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Kozuch, Michael J., and Mark Chadwick. "Azimuthal and regional variations of coda waves in New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 32, no. 3 (September 30, 1999): 170–79. http://dx.doi.org/10.5459/bnzsee.32.3.170-179.
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We present the results of using seismic waveform data to show that the elliptical nature of isoseismal distributions in New Zealand is related to regional structural trends. The data also suggest that there are regional and azimuthal variations in the attenuation of coda waves, which may need to be considered in ground motion attenuation relations.
We stacked over 20,000 waveforms from the New Zealand seismographic network. The data were filtered, normalized and stacked. Noisy or clipped records were down-weighted or removed. We also treated dense networks as a single station and generated a single stack for these networks. Stacks of shallow earthquake sources are presented by region and azimuth.
Variations in coda length throughout New Zealand suggest regions of high scattering. Strong azimuthal dependence in the coda is observed for non-volcanic zone stations. NE-SW waveform stacks, which follow the strike of the subduction zone, contain significantly longer codas than those with NW-SE raypaths. Long coda trains are also observed in the volcanic and geothermal zones yet there is little or no apparent azimuthal variation. These coda are particularly strong throughout the records which explains the difficulty analysts have had in picking S waves.
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Dowrick, David J. "Damage and intensities in the magnitude 7.8 1931 Hawke's Bay, New Zealand, earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 31, no. 3 (September 30, 1998): 139–63. http://dx.doi.org/10.5459/bnzsee.31.3.139-163.
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This paper is the result of a study of the shallow Mw = 7.8 Hawke's Bay earthquake which occurred in the North Island of New Zealand, 2 February 1931 (UT), and which was the final spur to the production of the first earthquake loadings code in New Zealand issued in 1935. This earthquake was a direct hit on two provincial towns (Napier and Hastings) and was the most damaging in New Zealand's history, causing the most casualties, major fires, and much damage to the built and natural environments. It gives the first overall description of the damage (to the buildings and lifelines) in this major event in modem earthquake engineering terms, and presents the first intensity map for the event determined directly in the Modified Mercalli (MM) scale. The zone which experienced the highest intensity (MM10) was confined to a modest area of onshore land (about 300 km2) above the centre of the rupture surface.
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Pizer, Charlotte, Kate Clark, Jamie Howarth, Ed Garrett, Xiaoming Wang, David Rhoades, and Sarah Woodroffe. "Paleotsunamis on the Southern Hikurangi Subduction Zone, New Zealand, Show Regular Recurrence of Large Subduction Earthquakes." Seismic Record 1, no. 2 (July 1, 2021): 75–84. http://dx.doi.org/10.1785/0320210012.
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Abstract Geological records of subduction earthquakes, essential for seismic and tsunami hazard assessment, are difficult to obtain at transitional plate boundaries, because upper-plate fault earthquake deformation can mask the subduction zone signal. Here, we examine unusual shell layers within a paleolagoon at Lake Grassmere, at the transition zone between the Hikurangi subduction zone and the Marlborough fault system. Based on biostratigraphic and sedimentological analyses, we interpret the shell layers as tsunami deposits. These are dated at 2145–1837 and 1505–1283 yr B.P., and the most likely source of these tsunamis was ruptures of the southern Hikurangi subduction interface. Identification of these two large earthquakes brings the total record of southern Hikurangi subduction earthquakes to four in the past 2000 yr. For the first time, it is possible to obtain a geologically constrained recurrence interval for the southern Hikurangi subduction zone. We calculate a recurrence interval of 500 yr (335–655 yr, 95% confidence interval) and a coefficient of variation of 0.27 (0.0–0.47, 95% confidence interval). The probability of a large subduction earthquake on the southern Hikurangi subduction zone is 26% within the next 50 yr. We find no consistent temporal relationship between subduction earthquakes and large earthquakes on upper-plate faults.
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Wotherspoon, Liam M., Rolando P. Orense, Mike Jacka, Russell A. Green, Brady R. Cox, and Clinton M. Wood. "Seismic Performance of Improved Ground Sites during the 2010–2011 Canterbury Earthquake Sequence." Earthquake Spectra 30, no. 1 (February 2014): 111–29. http://dx.doi.org/10.1193/082213eqs236m.
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The city of Christchurch and the surrounding region on the South Island of New Zealand are underlain by large areas of recent alluvial sediments and fills that are highly susceptible to liquefaction and seismic ground failure. Thus, the widespread liquefaction that occurred following the successive large-scale earth-quakes, with moment magnitudes (MW) ranging from 6.0 to 7.1 that struck the Canterbury region in 2010–2011 was expected. Prior to the series of earthquakes, soil improvement had been used at several sites to mitigate the anticipated damage. This paper reviews the performance of improved sites during the Canterbury earthquake sequence. The existing soil conditions at each site and the design of the ground improvement are discussed, together with descriptions of the post-earthquake damage observed. Moreover, liquefaction assessment within and surrounding a selection of the ground improvement zones is presented.
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Aziz Zanjani, Farzaneh, Guoqing Lin, and Clifford H. Thurber. "Nested regional-global seismic tomography and precise earthquake relocation along the Hikurangi subduction zone, New Zealand." Geophysical Journal International 227, no. 3 (July 28, 2021): 1567–90. http://dx.doi.org/10.1093/gji/ggab294.
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SUMMARY Seismic and geodetic examinations of the Hikurangi subduction zone (HSZ) indicate a remarkably diverse and complex system. Here, we investigate the 3-D P-wave velocity structure of the HSZ by applying an iterative, nested regional-global tomographic algorithm. The new model reveals enhanced details of seismic variations along the HSZ. We also relocate over 57 000 earthquakes using this newly developed 3-D model and then further improve the relative locations for 75 per cent of the seismicity using waveform cross-correlation. Double seismic zone characteristics, including occurrence, depth distribution and thickness change along the strike of the HSZ. An aseismic but fast Vp zone separates the upper and lower planes of seismicity in the southern and northern North Island. The upper plane of seismicity correlates with low Vp zones below the slab interface, indicating fluid-rich channels formed on top and/or within a dehydrated crust. A broad low Vp zone is resolved in the lower part of the subducting slab that could indicate hydrous mineral breakdown in the slab mantle. In the northern North Island and southern North Island, the lower plane of seismicity mostly correlates with the top of these low Vp zones. The comparison between the thermal model and the lower plane of seismicity in the northern North Island supports dehydration in the lower part of the slab. The mantle wedge of the Taupo volcanic zone (TVZ) is characterized by a low velocity zone underlying the volcanic front (fluid-driven partial melting), a fast velocity anomaly in the forearc mantle (a stagnant cold nose) and an underlying low velocity zone within the slab (fluids from dehydration). These arc-related anomalies are the strongest beneath the central TVZ with known extensive volcanism. The shallow seismicity (<40 km depth) correlates with geological terranes in the overlying plate. The aseismic impermeable terranes, such as the Rakaia terrane, may affect the fluid transport at the plate interface and seismicity in the overlying plate, which is consistent with previous studies. The deep slow slip events (25–60 km depths) mapped in the Kaimanawa, Manawatu and Kapiti regions coincide with low Vp anomalies. These new insights on the structure along the HSZ highlight the change in the locus of seismicity and dehydration at depth that is governed by significant variations in spatial and probably temporal attributes of subduction zone processes.
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Dowrick, David J., and David A. Rhoades. "Vulnerability of different classes of low-rise buildings in the 1987 Edgecumbe, New Zealand, earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 30, no. 3 (September 30, 1997): 227–41. http://dx.doi.org/10.5459/bnzsee.30.3.227-241.
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This paper describes an analysis of costs of damage to non-domestic buildings (all tow rise) in the Mw = 6.6 Edgecumbe New Zealand earthquake of 2 March 1987. The damage cost for each building was converted to a damage ratio by dividing it by the replacement value of that building. For the MM7 and MM9 intensity zones, the mean values and statistical distributions of these damage ratios were then found, the lognormal distribution fitting the data well. The data was then divided into subsets according to selected classes of construction, and the vulnerabilities of these classes were measured and compared in terms of their mean damage ratios and the associated 95% confidence limits. The classes of building examined included classifications by era of design, number of storeys, materials of construction, and building use. Valuable insights into earthquake resistant design and earthquake risk assessment parameters were obtained through the differences observed between classes, notably significant reductions in the vulnerability of buildings associated with improved ductility provisions.
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Bond, Sandy, and Sofia Dermisi. "Using GIS to measure the impact of the Canterbury earthquakes on house prices in Christchurch, NZ." International Journal of Disaster Resilience in the Built Environment 8, no. 02 (April 10, 2017): 123–38. http://dx.doi.org/10.1108/ijdrbe-05-2015-0027.
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Purpose Canterbury, New Zealand, experienced two significant earthquakes in 2010 and 2011 with a devastating impact on both houses and land. Negative media attention to the potential financial risks of living near or on the new Technical Category 3 (TC3) land or on land in a flood zone has fuelled the perception of uncertainty over the negative property price impacts. This research aims to determine if residents’ perceptions of the risks associated with various types of land zones (e.g. TC1, TC2 and TC3) are reflected in property prices. Design/methodology/approach This research analyses sale price patterns and the relationship between sale prices and house characteristics before and after both earthquakes. A three-step approach was taken by applying: an average trend analysis, Geographic Information Systems’ (GIS) hotspot analysis to identify possible spatial differentiations between the before and after-effects of the earthquakes and hedonic modelling to quantify the effect of house characteristics on sale price while controlling for and comparing three land zones (TC1 to TC3). Findings The data suggest that average sale prices increased after both quakes in TC1 and TC2 in contrast to TC3 zones, while close to 8,000 structures were demolished in red zones from 2010-2013 (supply was reduced). The econometric modelling suggests that higher sale prices are achieved by: newer houses across all land zones and more recent sale agreements only in TC1 and TC2 zones. Other observations include the effect of certain exterior façade materials on sale prices on the overall data set and in the individual TC1 and TC3 zones. In conclusion, the results suggest that although caution might exist for the TC3 zone, the quality of the house can override the stigma attached to the TC3 zones. Research limitations/implications A confounding factor in the research was that approximately 7,800 homes were rezoned red and/or demolished between 2010 and 2013 changing the supply and demand balance. Further, banks and other lenders updated their requirements for new lending on properties in the Canterbury region, requiring a number of reports from professionals such as structural engineers, geotechnical engineers and valuers before any new lending would be approved. Additionally, immediately after the September and February earthquakes, there was a 21-day stand-down period for earthquake-cover in Canterbury and without adequate insurance cover banks would not advance mortgage money, causing a short-term slowdown in the residential property market. Practical/implications The outcomes of this research will be of interest to government agencies tasked with assessing compensation for affected property owners. For example, the Earthquake Commission (EQC) developed a Diminution of Value Methodology for Increased Flooding Vulnerability that formed the basis of a High Court declaratory judgment decision in December 2014 that cleared the way for the EQC to start settling properties with increased flooding vulnerability. The EQC methodology was informed by the results of similar studies to this one, from around the world. Homeowners and rating valuers will also be interested in the results to understand how house prices have been affected by market perceptions towards earthquake damage, particularly in the worst-affected areas. Originality/value This study fills a research void regarding the price impacts of residents’ perceptions of the risks associated with various types of land zones that reflect the expected future liquefaction performance of the land.
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Andrews, A. L., and G. W. Butcher. "Intensity of shaking generated by large shallow New Zealand earthquakes." Bulletin of the New Zealand Society for Earthquake Engineering 25, no. 4 (December 31, 1992): 358–60. http://dx.doi.org/10.5459/bnzsee.25.4.358-360.
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Cape, C. D., R. M. O'Connor, J. M. Ravens, and D. J. Woodward. "Seismic expression of shallow structures in active tectonic settings in New Zealand." Exploration Geophysics 20, no. 2 (1989): 287. http://dx.doi.org/10.1071/eg989287.
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Late Cenozoic deformation along the Australian/Pacific plate boundary is seen in onshore New Zealand as zones characterised by extension- or transcurrent- or contraction-related structures. High-resolution multichannel seismic reflection data were acquired in several of these tectonic zones and successfully reveal the shallow structures within them. Thirty kilometres of dynamite reflection data in the Rangitaiki Plains, eastern Bay of Plenty, define a series of NE-trending normal faults within this extensional back-arc volcanic region. The data cross surface ruptures activated during the 1987 Edgecumbe earthquake. In the southern North Island, a 20 km Mini-Sosie? seismic profile details the Quaternary sedimentation history and reveals the structure of the active strike-slip and thrust fault systems that form the western and eastern edges of the Wairarapa basin, respectively. This basin is considered to sit astride the boundary between a zone of distributed strike-slip faults and an active accretionary prism. In the Nelson area, northwestern South Island, previously unrecognised low-angle thrust faults of Neogene or Quaternary age are seen from Mini-Sosie data to occur at very shallow depths. Crustal shortening here was previously thought to arise from movement on high-angle reverse faults, and the identification of these low-angle faults has prompted a reassessment of that model. A grid of 18 km of Mini-Sosie seismic data from the central eastern South Island delineates Neogene or Quaternary thrust faults in Cenozoic sediments. The thrusts are interpreted as reactivated Early Eocene normal faults, and the thrust fault geometry is dominated by these older structures.
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Macedo, Jorge, Norman Abrahamson, and Jonathan D. Bray. "Arias Intensity Conditional Scaling Ground‐Motion Models for Subduction Zones." Bulletin of the Seismological Society of America 109, no. 4 (June 18, 2019): 1343–57. http://dx.doi.org/10.1785/0120180297.
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Abstract Conditional ground‐motion models (CGMMs) for estimating Arias intensity (IA) for earthquakes in subduction zones are developed. The estimate of IA is conditioned in these models on the estimated peak ground acceleration (PGA), the spectral acceleration at T=1 s (SA1), time‐averaged shear‐wave velocity in the top 30 m (VS30), and magnitude (Mw). Random‐effects regressions are used to develop CGMMs for Japan, Taiwan, South America, and New Zealand. By combining the conditional models of IA with the ground‐motion models (GMMs) for PGA and SA1, the conditional models are converted to scenario‐based GMMs that can be used to estimate the median IA and its standard deviation directly for a given earthquake scenario and site conditions. The conditional scaling approach ensures the estimated IA values are consistent with a design spectrum that may correspond to above‐average spectral values for the controlling scenario. In addition, this approach captures the complex ground‐motion scaling effects found in GMMs for spectral acceleration, such as sediment‐depth effects, soil nonlinearity effects, and regionalization effects, in the developed scenario‐based models for IA. Estimates from the new scenario‐based IA models are compared to those from traditional GMMs for IA in subduction zones.
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Dowrick, D. J., and D. A. Rhoades. "Damage ratios for plant, equipment and stock in the 1987 Edgecumbe, New Zealand earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 28, no. 4 (December 31, 1995): 265–78. http://dx.doi.org/10.5459/bnzsee.28.4.265-278.
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This paper describes an analysis of damage costs to commercial and industrial equipment (plant) and stock in the Mw=6.6 Edgecumbe, New Zealand, earthquake of 2 March 1987. The damage costs were converted to damage ratios by dividing by the value of the relevant property parcel. The mean value and statistical distribution of damage ratios were found for various classes of equipment and stock in the MM7 and MM9 intensity Zones. The lognormal distribution generally fitted the data well.
Equipment and stock are much more variable in nature than modern buildings, and in large part are not designed for earthquakes. In this study they were analysed in subsets formed by classification according to Use (i.e. shops, offices, halls, residential or industrial) and Vulnerability (i.e. Robust, Medium or Fragile). These classifications provided useful insights into variations in the damage ratio. The overall mean damage ratio, Drm for stock was considerably higher than for equipment, even though Drm for Fragile equipment was higher than Drm for Fragile stock. This occurred because the proportion of stock that was Fragile was much larger than the corresponding proportion of equipment. The proportional difference in damage levels between Fragile and Robust property was greater at intensity MM7 than at MM9. This is consistent with the definitions of the Modified Mercalli scale. A comparison of the damage to equipment and buildings showed that, at MM9, the mean and distribution of damage ratios for Medium vulnerability equipment are similar to those for the associated single storey, post-code (1935+) commercial and industrial buildings.
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Scheele, Finn, Biljana Lukovic, Jose Moratalla, Alexandre Dunant, and Nick Horspool. "Estimating fire following earthquake risk for Wellington City, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 55, no. 4 (December 2, 2022): 241–56. http://dx.doi.org/10.5459/bnzsee.55.4.241-256.
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Fire following earthquake (FFE) is a significant hazard in urban areas subject to high seismicity. Wellington City has many characteristics that make it susceptible to ignitions and fire spread. These include proximity to major active faults, closely spaced timber-clad buildings, vulnerable water and gas infrastructure, frequent high winds and challenging access for emergency services. We modelled the ignitions, fire spread and suppression for five earthquake sources. Uncertainty in ground motions, the number and location of ignitions, weather conditions and firefighting capacity were accounted for. The mean loss per burn zone (area burnt due to ignition and fire spread) is $46m without fire suppression, indicating the potential property damage avoided by controlling the fire spread. The mean total loss for earthquake scenarios ranges from $0.28b for the Wairau Fault through to $3.17b for a Hikurangi Subduction Zone scenario, including the influence of fire suppression. Wind speed has a strong influence on the potential losses for each simulation and is a more significant factor than the number of ignitions for evaluating losses. Areas in Wellington City of relatively high risk are identified, which may inform risk mitigation strategies. The models may be applied to other urban areas.
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Pettinga, Jarg R., Mark D. Yetton, Russ J. Van Dissen, and Gaye Downes. "Earthquake source identification and characterisation for the Canterbury region, South Island, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 34, no. 4 (December 31, 2001): 282–317. http://dx.doi.org/10.5459/bnzsee.34.4.282-317.
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The Canterbury region of the South Island of New Zealand straddles a wide zone of active earth deformation associated with the oblique continent-continent collision between the Australian and Pacific tectonic plates east of the Alpine fault. The associated ongoing crustal strain is documented by the shallow earthquake activity (at depths of <40 km) and surface deformation expressed by active faulting, folding and ongoing geodetic strain. The level of earth deformation activity (and consequent earthquake hazard) decreases from the northwest to the southeast across the region. Deeper-level subduction related earthquake events are confined to the northernmost parts of the region, beneath Marlborough.
To describe the geological setting and seismological activity in the region we have sub-divided the Canterbury region into eight domains that are defined on the basis of structural styles of deformation. These eight domains provide an appropriate geological and seismological context on which seismic hazard assessment can be based. A further, ninth source domain is defined to include the Alpine fault, but lies outside the region.
About 90 major active earthquake source faults within and surrounding the Canterbury region are characterised in terms of their type (sense of slip), geometry (fault dimensions and attitude) and activity (slip rates, single event displacements, recurrence intervals, and timing of last rupture). In the more active, northern part of the region strike-slip and oblique strike-slip faults predominate, and recurrence intervals range from 81 to >5,000 years. In the central and southern parts of the region oblique-reverse and reverse/thrust faults predominate, and recurrence intervals typically range from -2,500 to >20,000 years.
In this study we also review information on significant historical earthquakes that have impacted on the region (e,g. Christchurch earthquakes 1869 and 1870; North Canterbury 1888; Cheviot 1902; Motunau 1922; Buller 1929; Arthurs Pass 1929 and 1994; and others), and the record of instrumental seismicity. In addition, data from available paleoseismic studies within the region are included; and we also evaluate large potential earthquake sources outside the Canterbury region that are likely to produce significant shaking within the region. The most important of these is the Alpine fault, which we include as a separate source domain in this study.
The integrated geological and seismological data base presented in this paper provide the foundation for the probabilistic seismic hazard assessment for the Canterbury region, and this is presented in a following companion paper in this Bulletin (Stirling et al. this volume).
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Farahani, Ali, Mahsa Moradikhaneghahi, Majid Ghayoomi, and Jennifer M. Jacobs. "Application of Soil Moisture Active Passive (SMAP) Satellite Data in Seismic Response Assessment." Remote Sensing 14, no. 17 (September 2, 2022): 4375. http://dx.doi.org/10.3390/rs14174375.
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The proven relationship between soil moisture and seismic ground response highlights the need for a tool to track the Earth’s surface soil moisture before and after seismic events. This paper introduces the application of Soil Moisture Active Passive (SMAP) satellite data for global soil moisture measurement during earthquakes and consequent events. An approach is presented to study areas that experienced high level of increase in soil moisture during eleven earthquakes. Two ancillary datasets, Global Precipitation Measurement (GPM) and Global Land Data Assimilation (GLDAS), were used to isolate areas that had an earthquake-induced increase in soil moisture from those that were due to hydrological processes. SMAP-based soil moisture changes were synthesized with seismic records developed by the United States Geological Survey (USGS), mapped ground failures in reconnaissance reports, and surface changes marked by Synthetic Aperture Radar (SAR)-based damage proxy maps. In the majority of the target earthquakes, including Croatia 2020, Greece 2020, Indonesia 2018, Taiwan 2016, Ecuador 2016, and Nepal 2015, a relationship between the SMAP soil moisture estimates and seismic events was evident. For these events, the earthquake-induced soil moisture response occurred in liquefaction-prone seismic zones. The New Zealand 2016 event was the only study region for which there was a clear inconsistency between ΔSMSMAP and the seismic records. The promising relationship between soil moisture changes and ground deformations indicates that SMAP would be a useful data resource for geotechnical earthquake engineering applications and reconnaissance efforts.
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Qin, K., L. X. Wu, A. De Santis, J. Meng, W. Y. Ma, and G. Cianchini. "Quasi-synchronous multi-parameter anomalies associated with the 2010–2011 New Zealand earthquake sequence." Natural Hazards and Earth System Sciences 12, no. 4 (April 16, 2012): 1059–72. http://dx.doi.org/10.5194/nhess-12-1059-2012.
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Abstract. Positive thermal anomalies about one month before the 3 September 2010 Mw = 7.1 New Zealand earthquake and "coincidental" quasi-synchronous fluctuations of GPS displacement were reported. Whether there were similar phenomena associated with the aftershocks? To answer it, the following was investigated: multiple parameters including surface and near-surface air temperature, surface latent heat flux, GPS displacement and soil moisture, using a long-term statistical analysis method. We found that local thermal and deformation anomalies appeared quasi-synchronously in three particular tectonic zones, not only about one month before the mainshock, but also tens of days before the 21 February 2011 Mw = 6.3 aftershock, and that the time series of soil moisture on the epicenter pixel had obvious peaks on most of the anomalous days. Based on local tectonic geology, hydrology and meteorology, the particular lithosphere-coversphere-atmosphere coupling mode is interpreted and four mechanisms (magmatic-hydrothermal fluids upwelling, soil moisture increasing, underground pore gases leaking, and positive holes activating and recombining) are discussed.
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Dowrick, D. J., and D. A. Rhoades. "Damage ratios for domestic buildings in the 1987 Edgecumbe earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 23, no. 2 (June 30, 1990): 137–49. http://dx.doi.org/10.5459/bnzsee.23.2.137-149.
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This paper describes an analysis of damage costs to house and farm property in the Ms = 6.6 Edgecumbe New Zealand earthquake of 2 March 1987. The study investigated damage ratios for dwellings, plus their associated garages and farm buildings. The damage costs were converted to damage ratios, by dividing them by the total value of the relevant property in the intensity zones concerned. The mean values and statistical distributions of these damage ratios were then found, the lognormal distribution fitting very well. The mean damage ratio for house buildings at MM intensity IX was 0.08, and the mean damage ratios were generally smaller than previous studies had shown.
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Whitehead, Neil Evan, and Ü. Ulusoy. "Origin of Earthquake Light Associated with Earthquakes in Christchurch, New Zealand, 2010-2011." Earth Sciences Research Journal 19, no. 2 (December 17, 2015): 113–20. http://dx.doi.org/10.15446/esrj.v19n2.47000.
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<p>Earthquake light (EQL) mainly blue-white flashes from the ground, was observed coseismically during a NewZealand M7.1 earthquake, (4.47 am 4-Sep-2010 local time). A local production mechanism is most probable. The blue-white flash observations support the Freund et al. mechanism, i.e. shockwave disturbance creating electronic“holes” from ruptured peroxy bonds in quartz, and subsequent surface positive charge from the ground, followed by light emission during neutralization. Examination of video records shows the flash median length is about half a second and needs to be differentiated from the light during electricity supply short circuits. Observed ground-level white colors appear to result from very intense non-specific air ionization. Blue colors seem to be nitrogen emission with a short lifetime, succeeded by green oxygen emissions with longer lifetime followed by much lower intensity red. These were created by transient low-to-moderate voltages and probably include significant UV production.The maximum likely radiation dose is small, restricted to the skin, and equivalent at most to a few months natural background radiation. Calculations confirm the release of <span style="vertical-align: super;">222</span>Rn is not the major mechanism for creating earthquake light, and would contribute minimal radiation dose. Other unique observations are: streamers of light changing from blue to green as they passed from west to east, vertical sheets of blue-green light from cracks in an asphalt road surface, created by local shockwaves and shearing forces, daylight observation by fishermen of rapid linear undersea travel of blue light seconds before a 2011 M6.0 aftershock, and a mid-day green-blue glow over nearby hills containing a fault zone, shortly before the further destructive M6.3 earthquake, (12.51 pm 22-Feb-2011). Origen de Luces de Terremoto Asociadas con los Terremotos de Christchurch, Nueva Zelanda, 2010-2011 son principalmente azul blancas y fueron cosísmicamente observadas durante un terremoto de magnitud 7.1 en Nueva Zelanda (4:47 a.m., 4 de septiembre de 2010, hora local). Es muy probable que el fenómeno haya sido producto de un mecanismo local. Las observaciones del destello azul blanco coinciden con el mecanismo de Freund y otros, esto es, la alteración de un movimiento sísmico que crea "agujeros" electrónicos a partir de lazos de ácido peroxi rotos en cuarzos, con carga positiva superficial consecuente del suelo, y seguida por la emisión de luz durante la neutralización. La revisión de grabaciones de video muestra que la duración del destello es de cerca de medio segundo y debe ser diferenciado de la luz generada por los cortos circuitos del fluido eléctrico. Los colores blancos observados a nivel del terreno parecen resultar de una intensa ionización aérea no específica. Los colores azules serían emisiones de nitrógeno con un corto período de duración, sucedidas por emisiones de oxígeno verde de mayor duración y seguidas por un rojo mucho menos intenso. Estos colores fueron creados por voltajes transitorios de bajo a moderados y probablemente incluyen una producción significativa de radiación ultravioleta. La cantidad de radiación máxima probable es pequeña, restringida a la piel, y equivalente a unos pocos meses de radiación natural regular. Los cálculos confirman que la liberación de <sup>222</sup>Rn (Radón) no es el principal mecanismo para crear las luces de terremoto y que este contribuye con una mínima cantidad de radiación. Otras observaciones únicas hablan de rayos de luz que cambian de azul a verde mientras van de oeste a este, de cortinas verticales de luz azul verdosa que emergen de grietas en la carretera, creadas por movimientos sísmicos y fuerzas de corte; de observaciones de pescadores a luz del día del trayecto subacuático, rápido y lineal, de una luz azul antes del movimiento sísmico de magnitud 6.0 de 2011, y de un resplandor verde azuloso a mediodía sobre las colinas cercanas a una zona de fallas momentos antes del destructivo terremoto de magnitud 6.3 (12:51 p.m., 22 de febrero de 2011).</p>
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Bradley, Brendon A., Liam M. Wotherspoon, and Anna E. Kaiser. "Ground motion and site effect observations in the wellington region from the 2016 Mw7.8 Kaikōura, New Zealand earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 50, no. 2 (June 30, 2017): 94–105. http://dx.doi.org/10.5459/bnzsee.50.2.94-105.
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This paper presents ground motion and site effect observations in the greater Wellington region from the 14 November 2016 Mw7.8 Kaikōura earthquake. The region was the principal urban area to be affected by the earthquake-induced ground motions from this event. Despite being approximately 60km from the northern extent of the causative earthquake rupture, the ground motions in Wellington exhibited long period (specifically T = 1 - 3s) ground motion amplitudes that were similar to, and in some locations exceeded, the current 500 year return period design ground motion levels. Several ground motion observations on rock provide significant constraint to understand the role of surficial site effects in the recorded ground motions. The largest long period ground motions were observed in the Thorndon and Te Aro basins in Wellington City, inferred as a result of 1D impedance contrasts and also basin-edge-generated waves. Observed site amplifications, based on response spectral ratios with reference rock sites, are seen to significantly exceed the site class factors in NZS1170.5:2004 for site class C, D, and E sites at approximately T=0.3-3.0s. The 5-95% Significant Duration, Ds595, of ground motions was on the order of 30 seconds, consistent with empirical models for this earthquake magnitude and source-to-site distance. Such durations are slightly longer than the corresponding Ds595 = 10s and 25s in central Christchurch during the 22 February 2011 Mw6.2 and 4 September 2010 Mw7.1 earthquakes, but significantly shorter than what might be expected for large subduction zone earthquakes that pose a hazard to the region. In summary, the observations highlight the need to better understand and quantify basin and near-surface site response effects through more comprehensive models, and better account for such effects through site amplification factors in design standards.
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Dowrick, D. J., and D. A. Rhoades. "Damage ratios for low-rise non-domestic brick buildings in the magnitude 7.1 Wairarapa, New Zealand, earthquake of 24 June 1942." Bulletin of the New Zealand Society for Earthquake Engineering 35, no. 3 (September 30, 2002): 135–48. http://dx.doi.org/10.5459/bnzsee.35.3.135-148.
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An analysis of damage costs to low-rise non-domestic brick buildings in the MM8 intensity zone of the Mw 7.1 Wairarapa earthquake of 24 June 1942 has evaluated the vulnerability of such buildings in New Zealand for the first time. The buildings studied were mostly of unreinforced brick of average workmanship and material quality, i.e. the second most vulnerable class of New Zealand buildings. Approximate vulnerabilities were also determined for partly reinforced and partly retrofitted buildings, and for one and two-storey buildings. The costs of damage were derived from insurance claims and local government records. The indicators of vulnerability that were determined were the statistical distributions and mean values of damage ratios, and the percentage of buildings damaged. Comparisons have also been made with results from studies of other earthquakes.
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Barnes, Philip M., Laura M. Wallace, Demian M. Saffer, Rebecca E. Bell, Michael B. Underwood, Ake Fagereng, Francesca Meneghini, et al. "Slow slip source characterized by lithological and geometric heterogeneity." Science Advances 6, no. 13 (March 2020): eaay3314. http://dx.doi.org/10.1126/sciadv.aay3314.
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Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) of well-documented SSEs at the Hikurangi subduction zone offshore New Zealand offers a unique opportunity to link geophysical imaging of the subduction zone with direct access to incoming material that represents the megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this incoming material before it is entrained immediately down-dip along the shallow plate interface. Drilling results, tied to regional seismic reflection images, reveal heterogeneous lithologies with highly variable physical properties entering the SSE source region. These observations suggest that SSEs and associated slow earthquake phenomena are promoted by lithological, mechanical, and frictional heterogeneity within the fault zone, enhanced by geometric complexity associated with subduction of rough crust.
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Quigley, M., R. Van Dissen, P. Villamor, N. Litchfield, D. Barrell, K. Furlong, T. Stahl, et al. "Surface rupture of the Greendale Fault during the Darfield (Canterbury) earthquake, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 43, no. 4 (December 31, 2010): 236–42. http://dx.doi.org/10.5459/bnzsee.43.4.236-242.
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The Mw 7.1 Darfield (Canterbury) earthquake of 4 September 2010 (NZST) was the first earthquake in New Zealand to produce ground-surface fault rupture since the 1987 Edgecumbe earthquake. Surface rupture of the previously unrecognised Greendale Fault during the Darfield earthquake extends for at least 29.5 km and comprises an en echelon series of east-west striking, left-stepping traces. Displacement is predominantly dextral strike-slip, averaging ~2.5 m, with maxima of ~5 m along the central part of the rupture. Maximum vertical displacement is ~1.5 m, but generally < 0.75 m. The south side of the fault has been uplifted relative to the north for ~80% of the rupture length, except at the eastern end where the north side is up. The zone of surface rupture deformation ranges in width from ~30 to 300 m, and comprises discrete shears, localised bulges and, primarily, horizontal dextral flexure. At least a dozen buildings were affected by surface rupture, but none collapsed, largely because most of the buildings were relatively flexible and robust timber-framed structures and because deformation was distributed over tens to hundreds of metres width. Many linear features, such as roads, fences, power lines, and irrigation ditches were offset or deformed by fault rupture, providing markers for accurate determinations of displacement.
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Bowman, Ian. "Conservation of historic buildings in a seismic zone." Bulletin of the New Zealand Society for Earthquake Engineering 21, no. 2 (June 30, 1988): 128–34. http://dx.doi.org/10.5459/bnzsee.21.2.128-134.
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Following the accepted principles and practice of conservation of historic buildings in New Zealand is complicated by the proximity to earthquake activity. The author's own research, outlined in this article, draws some conclusions.
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YING, Fei J., Suzanne WILKINSON, and Jim CORNER. "CHALLENGES TO SEISMIC REHABILITATION DECISION PROCESS IN NEW ZEALAND: A FOCUS OF DECISION ENVIRONMENT." International Journal of Strategic Property Management 20, no. 3 (July 19, 2016): 305–15. http://dx.doi.org/10.3846/1648715x.2016.1190419.
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Implementing seismic rehabilitation requires a substantial investment for substandard building owners. Seismic retrofitting can significantly reduce earthquake damages to the built environment and thus decrease the risk posing to the public and the community. However, many countries with active seismic zones, including New Zealand, experience slow progress of seismic retrofit. This paper examines the decision environment which has significant impact on stakeholders’ behaviours, to identify challenges in seismic rehabilitation decision-making. A qualitative approach was adopted with semi-structured interviews. A selection of building owners, government officials, and practical professionals involved in seismic retrofitting decision-making were interviewed. Major challenges identified by the interview results include various options, diverse considerations, assorted stakeholders, conflicting multiple objectives, and unaided decision making process. The inconsistency in expectation of whether building owners have sufficient aid in decision-making process offers plausible explanation regarding the key impediment to successful seismic rehabilitation decisions. A decision-making model is thus a necessity to assist building owners making an informed decision.
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Cochran, U., K. Berryman, J. Zachariasen, D. Mildenhall, B. Hayward, K. Southall, C. Hollis, et al. "Paleoecological insights into subduction zone earthquake occurrence, eastern North Island, New Zealand." Geological Society of America Bulletin 118, no. 9-10 (September 1, 2006): 1051–74. http://dx.doi.org/10.1130/b25761.1.
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Dowrick, David J. "Revised isoseismal maps for the 1956 Bay of Plenty and 1987 Edgecumbe, New Zealand, earthquakes." Bulletin of the New Zealand Society for Earthquake Engineering 40, no. 4 (December 31, 2007): 200–206. http://dx.doi.org/10.5459/bnzsee.40.4.200-206.
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The Modified Mercalli intensities of the 1956 Mw 6.3 Bay of Plenty and 1987 Mw 6.5 Edgecumbe earthquakes have recently been reviewed and about one-third of them were found to be erroneous. The resulting revisions to their isoseismal maps are substantial, and both new maps now show the strong influence of the high attenuation in the Taupo Volcanic Zone (TVZ). An analysis of the causes of the errors in the intensities is given. The new maps will help improve the modelling of attenuation in the TVZ, and will contribute to improvements in assessments of seismic hazard and risk in that region. An important implication is that the mean damage ratios estimated from studies of damage costs in the Edgecumbe earthquake by Dowrick and Rhoades are likely to be erroneously low, and need to be reviewed.
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Bloom, Colin K., Andrew Howell, Timothy Stahl, Chris Massey, and Corinne Singeisen. "The influence of off-fault deformation zones on the near-fault distribution of coseismic landslides." Geology 50, no. 3 (November 22, 2021): 272–77. http://dx.doi.org/10.1130/g49429.1.
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Abstract Coseismic landslides are observed in higher concentrations around surface-rupturing faults. This observation has been attributed to a combination of stronger ground motions and increased rock mass damage closer to faults. Past work has shown it is difficult to separate the influences of rock mass damage from strong ground motions on landslide occurrence. We measured coseismic off-fault deformation (OFD) zone widths (treating them as a proxy for areas of more intense rock mass damage) using high-resolution, three-dimensional surface displacements from the 2016 Mw 7.8 Kaikōura earthquake in New Zealand. OFD zones vary in width from ~50 m to 1500 m over the ~180 km length of ruptures analyzed. Using landslide densities from a database of 29,557 Kaikōura landslides, we demonstrate that our OFD zone captures a higher density of coseismic landslide incidence than generic “distance to fault rupture” within ~650 m of surface fault ruptures. This result suggests that the effects of rock mass damage within OFD zones (including ground motions from trapped and amplified seismic waves) may contribute to near-fault coseismic landslide occurrence in addition to the influence of regional ground motions, which attenuate with distance from the fault. The OFD zone represents a new path toward understanding, and planning for, the distribution of coseismic landslides around surface fault ruptures. Inclusion of estimates of fault zone width may improve landslide susceptibility models and decrease landslide risk.
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Hurst, Tony, Stephen Bannister, Russell Robinson, and Bradley Scott. "Characteristics of three recent earthquake sequences in the Taupo Volcanic Zone, New Zealand." Tectonophysics 452, no. 1-4 (June 2008): 17–28. http://dx.doi.org/10.1016/j.tecto.2008.01.017.
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Dowrick, D. J., D. A. Rhoades, J. Babor, and R. D. Beetham. "Damage ratios for houses and microzoning effects in Napier in the magnitude 7.8 Hawke's Bay, New Zealand earthquake of 1931." Bulletin of the New Zealand Society for Earthquake Engineering 28, no. 2 (June 30, 1995): 134–45. http://dx.doi.org/10.5459/bnzsee.28.2.134-145.
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This paper describes the analysis of a large data base of actual costs of damage to houses in Napier in the magnitude Ms = 7.8 Hawke's Bay earthquake of 1931. This event occurred prior to the introduction of any earthquake design regulations in New Zealand. The town of Napier was sited over the source of this large shallow event, and therefore it may be presumed that it was subjected to about the strongest shaking likely to occur in an earthquake. Mean values and statistical distributions of damage ratios have been estimated for houses built on rock, on firm beach deposits, and on soft recent alluvium. This is the first time world-wide that a fully representative quantification of damage has been made for a zone of such strong earthquake shaking, for any class of construction, with or without quantification of microzoning effects. This study examines the damage to housing due to ground shaking and ground damage, and excludes the effects of earthquake-induced fires.
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Cubrinonski, Misko, Brendon Bradley, Frederick Wentz, and Ananth Balachandra. "Re-evaluation of New Zealand seismic hazard for geotechnical assessment and design." Bulletin of the New Zealand Society for Earthquake Engineering 55, no. 1 (March 1, 2022): 1–14. http://dx.doi.org/10.5459/bnzsee.55.1.1-14.
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This paper scrutinises the seismic hazard of New Zealand (NZ) from a geotechnical engineering perspective. The two codified versions of the seismic hazard in NZS1170.5 (structural loading standard) and NZTA Bridge Manual (NZTA-BM) are shown to yield consistently different peak ground acceleration (PGA) hazards throughout NZ. Results from site-specific PSHA for 24 locations in NZ are used to examine key hazard characteristics, including earthquake magnitude and the effects of site conditions (classes) on the PGA hazard. The comparative evaluations show that for most of the locations considered, NZS1170.5 and NZTA-BM overestimate the PGA hazard. However, NZS1170.5, and NZTA-BM in particular, significantly underestimate the PGA hazard for locations that are at a short source-to-site distance from the Hikurangi Subduction Zone (HSZ), and for which HSZ significantly contributes to their hazard. Using the results from this study, an interim PGA hazard is recommended for geotechnical assessment and design in support of the NZ guidelines for geotechnical earthquake engineering practice. The recommended interim PGA hazard is applicable to all site classes without any modification or use of site amplification factors.
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Vinogradov, Yuri, Marina Ryzhikova, Natalia Petrova, Svetlana Poygina, and Marina Kolomiets. "Global earthquakes in the 2021 first half according to the GS RAS." Russian Journal of Seismology 3, no. 3 (September 28, 2021): 7–27. http://dx.doi.org/10.35540/2686-7907.2021.3.01.
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Data on the 2021 first half Earth seismicity at the level of strong earthquakes with magni-tudes mb6.0 according to the Alert Service of the Geophysical Survey RAS are given. The review also includes information on 81 earthquakes in Russia and adjacent territories, felt in the settlements of the Russian Federation. For 14 strong earthquakes, within one or two days after their occurrence, Informational messages were published, and information about the focal mechanisms was giving. The strongest earthquake of the Earth with MS=7.8 (Mw=8.1) occurred on March 4 at the Kermadec Islands, New Zealand. The largest human casualties and material damage during the study period were caused by catastrophic earth-quakes with MS=5.1 (Mw=5.8) and MS=5.9 (Mw=6.3), which occurred on January 14 at the Sulawesi Island, Indonesia. As a result of the earthquakes, 81 people died, 826 were injured. The strongest earthquake in Russia was the March 16 earthquake with MS=6.7 (Mw=6.6) off the eastern coast of Kamchatka. The maximum shaking intensity in Russia (I=6) was manifested by the strong Khuvsgul earthquake with MS=7.2 (Mw=6.8), which took place on January 11 in the Northern Mongolia, near the border with Russia. The position of the main shock and its aftershocks indicate the intensification of the seismic process in the north-western part of the Khuvsgul rift zone. According to the focal mechanisms of the main shock and two strong aftershocks, the stress of the northwest/southeast extension prevails in this zone, and the predominant slip type along the faults of the northeast strike is a nor-mal fault. The global seismic energy released in the 2021 first half remains, as in the previ-ous two years, at a reduced level, relative to the average for the last 11.5 years, which indi-cates a continuing seismic calm.
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Jadhav, Kalyani. "Comparative Study, Design and Analysis of a G+12 Structure in Earthquake Zone in India." International Journal for Research in Applied Science and Engineering Technology 9, no. VII (July 25, 2021): 2319–29. http://dx.doi.org/10.22214/ijraset.2021.36719.
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Seismic isolation is a technology that decouples a building structure from the damaging earthquake motion. It is a simple structural design approach to mitigate or reduce potential earthquake damage. In base-isolated structures, the seismic protection is obtained by shifting the natural period of the structure away from the range of the frequencies for which the maximum amplification effects of the ground motion are expected; thus, the seismic input energy is significantly reduced. At the same time, the reduction of the high deformations attained at the base of the structure is possible, thanks to the energy dissipation caused by the damping and the hysteretic properties of these devices, further improving the reduction of responses of the structures. Base isolation is also an attractive retrofitting strategy to improve the seismic performance of existing bridges and monumental historic building. The method of base isolation was developed in an attempt to mitigate the effects of earthquakes on buildings during earthquakes and has been practically proven to be the one of the very effective methods in the past several decades. Base isolation consists of the installation of support mechanism which decouples the structure from earthquake induced ground motions. Base isolation allows to filter the input forcing functions and to avoid acceleration seismic forces on the structure. If the structure is separated from the ground during an earthquake, the ground is moving but the structure experienced little movement. To minimize the transmission of potentially damaging earthquake ground motions into a structure is achieved by the introduction of flexibility at the base of the structure in the horizontal direction while at the same time introducing damping elements to restrict the amplitude or extent of the motion caused by the earthquake somewhat akin to shock absorbers. In recent years this relatively new technology has emerged as a practical and economic alternative to conventional seismic strengthening. This concept has received increasing academic and professional attention and is being applied to a wide range of civil engineering structures. To date there are several hundred buildings in Japan, New Zealand, United States, India which use seismic isolation principles and technology for their seismic design.
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Kearse, Jesse, Yoshihiro Kaneko, Tim Little, and Russ Van Dissen. "Curved slickenlines preserve direction of rupture propagation." Geology 47, no. 9 (July 10, 2019): 838–42. http://dx.doi.org/10.1130/g46563.1.
Full textAbstract:
Abstract Slip-parallel grooves (striations) on fault surfaces are considered a robust indicator of fault slip direction, yet their potential for recording aspects of earthquake rupture dynamics has received little attention. During the 2016 Kaikōura earthquake (South Island, New Zealand), >10 m of dextral strike-slip on the steeply dipping Kekerengu fault exhumed >200 m2 of fresh fault exposure (free faces) where it crossed bedrock canyons. Inscribed upon these surfaces, we observed individual striae up to 6 m long, all of which had formed during the earthquake. These were typically curved. Using simulations of spontaneous dynamic rupture on a vertical strike-slip fault, we reproduce the curved morphology of striae on the Kekerengu fault. Assuming strike-slip pre-stress, our models demonstrate that vertical tractions induced by slip in the so-called cohesive zone result in transient changes in slip direction. We show that slip-path convexity is sensitive to the direction of rupture propagation. To match the convexity of striae formed in 2016 requires the rupture to have propagated in a northeast direction, a prediction that matches the known rupture direction of the Kaikōura earthquake. Our study highlights the potential for fault striae to record aspects of rupture dynamics, including the rupture direction of paleo strike-slip earthquakes.
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Destegul, Umut, Grant Dellow, and David Heron. "A ground shaking amplification map for New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 42, no. 2 (June 30, 2009): 122–28. http://dx.doi.org/10.5459/bnzsee.42.2.122-128.
Full textAbstract:
A ground shaking amplification map of New Zealand has been compiled from data held by GNS Science. The resulting map is being used in RiskScape, a tool for comparing risks at a given site from a variety of hazards by estimating potential losses.
A GIS-based geological map with national coverage has been composed from several sources, and is used as the base data. Geological maps from the QMAP project (an ongoing project to digitally compile 1:250,000 geological maps for all of New Zealand) have been used where available, supplemented with detailed geological maps at scales ranging from 1:25,000 to 1:50,000 for the larger urban areas. Gaps in the QMAP series have been filled by the 1:1,000,000 ‘Geological Map of New Zealand’.
Every geological polygon in the composite geological map has been assigned one of the ground shaking amplification (or site) classes from the New Zealand Standard for Structural Design Actions – Earthquake actions (NZS 1170.5) to produce the result map. These conform to the site class definitions in NZS 1170.5, which describes five classes with respect to ground shaking amplification. Assignment of these classes was straightforward for rock sites but more involved for soils where, for example, at boundaries between weak rock and deep soil sites a buffer zone of shallow soil was applied.
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Gómez-Vasconcelos, MG, P. Villamor, SJ Cronin, J. Procter, G. Kereszturi, A. Palmer, D. Townsend, G. Leonard, K. Berryman, and S. Ashraf. "Earthquake history at the eastern boundary of the South Taupo Volcanic Zone, New Zealand." New Zealand Journal of Geology and Geophysics 59, no. 4 (July 4, 2016): 522–43. http://dx.doi.org/10.1080/00288306.2016.1195757.
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Madley, Megan, Alexander Yates, Martha Savage, Weiwei Wang, Tomomi Okada, Satoshi Matsumoto, Yoshihisa Iio, and Katrina Jacobs. "Velocity changes around the Kaikōura earthquake ruptures from ambient noise cross-correlations." Geophysical Journal International 229, no. 2 (December 22, 2021): 1357–71. http://dx.doi.org/10.1093/gji/ggab514.
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SUMMARY Seismic velocity changes before and after large-magnitude earthquakes carry information about damage present in the surrounding region. This study presents temporal velocity changes detected prior to and following the 2016 November Mw 7.8 Kaikōura earthquake in Canterbury, New Zealand. We use continuous waveform data from 11 short-period seismometers within the Kaikōura region with an average interstation distance of 83 km. Nine-component day-long empirical Green’s functions were computed for frequencies between 0.1 and 0.9 Hz for continuous seismic records from 2012 January 1 to 2018 February 28, which also include the 2013 Cook Strait and Lake Grassmere earthquakes. Using the moving-window cross-spectral method, seismic velocity changes were calculated. Immediately following the 2016 Kaikōura earthquake, a decrease in seismic velocity averaged across all component pairs of approximately 0.2 per cent was observed. An increase in seismic velocity of approximately 0.1 per cent after the earthquake was visible over a 1.5 yr period averaged across all component pairs. A depth sensitivity analysis suggests that observed velocity changes were confined to the uppermost 5 km of the subsurface. We consider strong ground motions a likely candidate for the seismic velocity decrease, followed by post-seismic relaxation via crack healing of the faults that ruptured in the Kaikōura region. Fault-zone damage may also have contributed to observed decreases in the vicinity of ruptured faults.
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Oyarzo-Vera, Claudio, and Michael C. Griffith. "The Mw 6.3 Abruzzo (Italy) earthquake of April 6th, 2009." Bulletin of the New Zealand Society for Earthquake Engineering 42, no. 4 (December 31, 2009): 302–7. http://dx.doi.org/10.5459/bnzsee.42.4.302-307.
Full textAbstract:
On April 6th, 2009, at 3:32 am local time, a Mw 6.3 earthquake struck the Abruzzo region in Italy. This earthquake killed 305 people, with a further 1,500 people injured and approximately 15,000 buildings damaged. Many buildings of significant historical and architectural value were destroyed and several modern buildings were also severely damaged with some having fully collapsed.
The authors visited the disaster zone one month after the earthquake. The most badly affected areas in L’Aquila historical centre and three other villages – San Gregorio, Pagánica and Onna – were inspected.
The main observations made during this reconnaissance trip are briefly presented, highlighting the relevant lessons for engineering practice in New Zealand and Australia.
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Stirling, Mark W., N. J. Litchfield, Pilar Villamor, Russ J. Van Dissen, Andy Nicol, Jarg Pettinga, Philip Barnes, et al. "The Mw7.8 2016 Kaikōura earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 50, no. 2 (June 30, 2017): 73–84. http://dx.doi.org/10.5459/bnzsee.50.2.73-84.
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We provide a summary of the surface fault ruptures produced by the Mw7.8 14 November 2016 Kaikōura earthquake, including examples of damage to engineered structures, transportation networks and farming infrastructure produced by direct fault surface rupture displacement. We also provide an overview of the earthquake in the context of the earthquake source model and estimated ground motions from the current (2010) version of the National Seismic Hazard Model (NSHM) for New Zealand. A total of 21 faults ruptured along a c.180 km long zone during the earthquake, including some that were unknown prior to the event. The 2010 version of the NSHM had considered multi-fault ruptures in the Kaikōura area, but not to the degree observed in the earthquake. The number of faults involved a combination of known and unknown faults, a mix of complete and partial ruptures of the known faults, and the non-involvement of a major fault within the rupture zone (i.e. the Hope Fault) makes this rupture an unusually complex event by world standards. However, the strong ground motions of the earthquake are consistent with the high hazard of the Kaikōura area shown in maps produced from the NSHM.
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Stringer, Mark E., Sarah Bastin, Christopher R. McGann, Claudio Cappellaro, Maya El Kortbawi, Rebecca McMahon, Liam M. Wotherspoon, et al. "Geotechnical aspects of the 2016 Kaikōura earthquake on the South Island of New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 50, no. 2 (June 30, 2017): 117–41. http://dx.doi.org/10.5459/bnzsee.50.2.117-141.
Full textAbstract:
The magnitude Mw7.8 ‘Kaikōura’ earthquake occurred shortly after midnight on 14 November 2016. This paper presents an overview of the geotechnical impacts on the South Island of New Zealand recorded during the post-event reconnaissance.
Despite the large moment magnitude of this earthquake, relatively little liquefaction was observed across the South Island, with the only severe manifestation occurring in the young, loose alluvial deposits in the floodplains of the Wairau and Opaoa Rivers near Blenheim. The spatial extent and volume of liquefaction ejecta across South Island is significantly less than that observed in Christchurch during the 2010-2011 Canterbury Earthquake Sequence, and the impact of its occurrence to the built environment was largely negligible on account of the severe manifestations occurring away from the areas of major development.
Large localised lateral displacements occurred in Kaikōura around Lyell Creek. The soft fine-grained material in the upper portions of the soil profile and the free face at the creek channel were responsible for the accumulation of displacement during the ground shaking. These movements had severely impacted the houses which were built close (within the zone of large displacement) to Lyell Creek. The wastewater treatment facility located just north of Kaikōura also suffered tears in the liners of the oxidation ponds and distortions in the aeration system due to ground movements.
Ground failures on the Amuri and Emu Plains (within the Waiau Valley) were small considering the large peak accelerations (in excess of 1g) experienced in the area. Minor to moderate lateral spreading and ejecta was observed at some bridge crossings in the area. However, most of the structural damage sustained by the bridges was a result of the inertial loading, and the damage resulting from geotechnical issues were secondary.
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Van Dissen, Russ J., Timothy Stahl, Andrew King, Jarg R. Pettinga, Clark Fenton, Timothy A. Little, Nicola J. Litchfield, et al. "Impacts of surface fault rupture on residential structures during the 2016 Mw 7.8 Kaikōura earthquake, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering 52, no. 1 (March 31, 2019): 1–22. http://dx.doi.org/10.5459/bnzsee.52.1.1-22.
Full textAbstract:
Areas that experience permanent ground deformation in earthquakes (e.g., surface fault rupture, slope failure, and/or liquefaction) typically sustain greater damage and loss compared to areas that experience strong ground shaking alone. The 2016 Mw 7.8 Kaikōura earthquake generated ≥220 km of surface fault rupture. The amount and style of surface rupture deformation varied considerably, ranging from centimetre-scale distributed folding to metre-scale discrete rupture. About a dozen buildings – mainly residential (or residential-type) structures comprising single-storey timber-framed houses, barns and wool sheds with lightweight roofing material – were directly impacted by surface fault rupture with the severity of damage correlating with both local discrete fault displacement and local strain. However, none of these buildings collapsed. This included a house built directly atop a discrete rupture that experienced ~10 m of lateral offset. The foundation and flooring system of this structure allowed decoupling of much of the ground deformation from the superstructure thus preventing collapse. Nevertheless, buildings directly impacted by surface faulting suffered greater damage than comparable structures immediately outside the zone of surface rupture deformation. From a life-safety standpoint, all these buildings performed satisfactorily and provide insight into construction styles that could be employed to facilitate non-collapse performance resulting from surface fault rupture and, in certain instances, even post-event functionality.