Articoli di riviste: "Low-To-Moderate seismicity"

1

C.V.R.Murty e Javed N. Malik. "Challenges of Low-to-Moderate Seismicity in India". Electronic Journal of Structural Engineering, n. 01 (28 marzo 2008): 77–87. http://dx.doi.org/10.56748/ejse.8801.

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India is a vast country that is growing even faster. Particularly over the last decade, there has been a sudden spurt in the construction activity in the country, especially in the large low-to-moderate seismic regions of the country. But, no systems are in place to regulate these massive constructions to ensure seismic safety. This paper raises the challenges in the current practice and provides measures to overcome them. In particular, the paper argues for separate provisions for the design and construction of structures in low-tomoderate seismic regions.

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Fardipour, M., E. L.umantarna, N. Lam, J. Wilson e E. Gad. "Drift Demand Predictions in Low to Moderate Seismicity Regions". Australian Journal of Structural Engineering 11, n. 3 (gennaio 2010): 195–206. http://dx.doi.org/10.1080/13287982.2010.11465066.

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Mergos, Panagiotis E., e Katrin Beyer. "Loading protocols for European regions of low to moderate seismicity". Bulletin of Earthquake Engineering 12, n. 6 (9 marzo 2014): 2507–30. http://dx.doi.org/10.1007/s10518-014-9603-3.

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Kim, Hyung-Joon, e Dong-Hyeon Shin. "Analytical Evaluation of MCE Collapse Performance of Seismically Base Isolated Buildings Located at Low-to-Moderate Seismicity Regions". Applied Sciences 10, n. 24 (21 dicembre 2020): 9150. http://dx.doi.org/10.3390/app10249150.

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The promising seismic response emerged by the concept of base isolation leads to increasing practical applications into buildings located at low-to-moderate seismicity regions. However, it is questionable that their collapse capacities can be ensured with reasonable reliability, although they would be designed according to a current seismic design code. This paper aims to investigate the collapse capacities of isolated buildings governed by the prescribed design criteria on the displacement and strength capacities of the employed isolation systems. In order to evaluate their collapse capacity under maximum considered earthquakes (MCEs), simplified numerical models are constructed for a larger number of nonlinear incremental dynamic analyses. The influential factors on the collapse probabilities of the prototype buildings are found out to specifically suggest the potential modifications of the design requirements. Although the MCE collapse probabilities of all isolated buildings are smaller than those expected for typical non-isolated buildings, these values are significantly different according to the degree of seismicity. The MCE collapse probabilities are dependent upon the governing collapse mechanism and the total system uncertainty. For the prototype buildings located at low-to-moderate seismicity regions, this study proposed the acceptable uncertainty to achieve a similar collapse performance to the corresponding buildings built at high seismicity regions.

5

Nordenson, Guy J. P., e Glenn R. Bell. "Seismic Design Requirements for Regions of Moderate Seismicity". Earthquake Spectra 16, n. 1 (febbraio 2000): 205–25. http://dx.doi.org/10.1193/1.1586091.

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The need for earthquake-resistant construction in areas of low-to-moderate seismicity has been recognized through the adoption of code requirements in the United States and other countries only in the past quarter century. This is largely a result of improved assessment of seismic hazard and examples of recent moderate earthquakes in regions of both moderate and high seismicity, including the San Fernando (1971), Mexico City (1985), Loma Prieta (1989), and Northridge (1994) earthquakes. In addition, improved understanding and estimates of older earthquakes in the eastern United States such as Cape Ann (1755), La Malbaie, Quebec (1925), and Ossippe, New Hampshire (1940), as well as monitoring of micro-activity in source areas such as La Malbaie, have increased awareness of the earthquake potential in areas of low-to-moderate seismicity. Both the hazard and the risk in moderate seismic zones (MSZs) differ in scale and kind from those of the zones of high seismicity. Earthquake hazards mitigation measures for new and existing construction need to be adapted from those prevailing in regions of high seismicity in recognition of these differences. Site effects are likely to dominate the damage patterns from earthquakes, with some sites suffering no damage not far from others, on soft soil, suffering near collapse. A number of new seismic codes have been developed in the past quarter century in response to these differences, including the New York City (1995) and the Massachusetts State (1975) seismic codes. Over the same period, the national model building codes that apply to most areas of low-to-moderate seismicity in the United States, the Building Officials and Code Administrators (BOCA) Code and the Southern Standard Building Code (SSBC), have incorporated up-to-date seismic provisions. The seismic provisions of these codes have been largely inspired by the National Earthquake Hazard Reduction Program (NEHRP) recommendations. Through adoption of these national codes, many state and local authorities in areas of low-to-moderate seismicity now have reasonably comprehensive seismic design provisions. This paper will review the background and history leading up to the MSZ codes, discuss their content, and propose directions for future development.

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R.K.L. Su. "Seismic Behaviour of Buildings with Transfer Structures in Low-to- Moderate Seismicity Regions". Electronic Journal of Structural Engineering, n. 01 (28 marzo 2008): 99–109. http://dx.doi.org/10.56748/ejse.9001.

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A literature review has been conducted aimed at improving the general understanding of the seismic response of concrete buildings with transfer structures in low-to-moderate seismicity regions. This paper summarizes and discusses the existing codified requirements for transfer structure design under seismic conditions. Based on the previous shaking table test results and numerical findings, the seismic effects on the inelastic behaviours of transfer structures are investigated. The mechanisms for the formation of a soft storey below transfer floors, the abrupt change in inter-storey drift near transfer storeys and shear concentration due to local deformation of transfer structures are developed. Design principles have been established for controlling soft-storey type failure and minimizing shear concentration in exterior walls supported by transfer structures. The influence of the vertical positioning of transfer floors on the seismic response of buildings has also been reviewed.

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Tsang, Hing-Ho. "Evaluation of codified elastic design spectrum models for regions of low-to-moderate seismicity". Soil Dynamics and Earthquake Engineering 70 (marzo 2015): 148–52. http://dx.doi.org/10.1016/j.soildyn.2014.12.016.

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Kanyilmaz, Alper, Hervé Degée e Carlo Andrea Castiglioni. "An adjusted design approach for concentrically braced frames in low-to-moderate seismicity areas". Bulletin of Earthquake Engineering 16, n. 9 (2 luglio 2018): 4159–89. http://dx.doi.org/10.1007/s10518-018-0402-0.

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Wilson, John, Nelson Lam e L. Pham. "Development of the New Australian Earthquake Loading Standard". Electronic Journal of Structural Engineering, n. 01 (28 marzo 2008): 25–31. http://dx.doi.org/10.56748/ejse.8301.

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This paper outlines the development of the Australian Earthquake Loading Standard, AS1170.4 published in 2007. Australia is a country of low to moderate seismicity with a number of Magnitude 6.8 events recorded and a moderate 5.6 magnitude event in Newcastle in 1989 that killed 13 people and caused in excess of $2 Billion damage. A new design response spectrum has been developed for Australia which has a very good representation of accelerations, velocities and displacements for rock and soft soil sites. The methodology used to develop the spectrum could be extended to other countries of low to moderate seismicity. The Standard introduces a tiered approach to earthquake loading from a simplistic force based approach to a more complex displacement based method. The displacement based method has significant advantages in low seismic regions and allows designers to design for gravity and wind loads and then to carry out a displacement check for earthquake effects.

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Islam, A. B. M. Saiful, Syed Ishtiaq Ahmad, Mohammed Jameel e Mohd Jumaat Zamin. "Seismic Base Isolation for Buildings in Regions of Low to Moderate Seismicity: Practical Alternative Design". Practice Periodical on Structural Design and Construction 17, n. 1 (febbraio 2012): 13–20. http://dx.doi.org/10.1061/(asce)sc.1943-5576.0000093.

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Tsang, H. H., J. L. Wilson, N. T. K. Lam e R. K. L. Su. "A design spectrum model for flexible soil sites in regions of low-to-moderate seismicity". Soil Dynamics and Earthquake Engineering 92 (gennaio 2017): 36–45. http://dx.doi.org/10.1016/j.soildyn.2016.09.035.

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Wilson, J. L., A. J. Robinson e T. Balendra. "Performance of precast concrete load-bearing panel structures in regions of low to moderate seismicity". Engineering Structures 30, n. 7 (luglio 2008): 1831–41. http://dx.doi.org/10.1016/j.engstruct.2007.12.008.

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Lam, Nelson, e Emad Gad. "Overturning of Non-Structural Components in Low-Moderate Seismicity Regions". Electronic Journal of Structural Engineering, n. 01 (28 marzo 2008): 121–32. http://dx.doi.org/10.56748/ejse.9201.

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The objective of this paper is to review key issues concerned with the proper engineering of non-structural components in buildings for their safe and satisfactory performances in projected seismic conditions in regions of low and moderate seismicity. Initially, the paper provides an overview of the conventional force-based provisions for the calculation of the required strengths for full restraints of non-structural components. Given the relatively small displacement demand of the ground in conditions of low and moderate seismicity, provisions for protection of non-structural components should only target at items which have been identified to be vulnerable to overturning and their failure can have serious consequences. In this context, the displacement-based (DB) model for overturning and its linearisation is presented. The DB model can potentially become very useful as technical reference when it comes to identifying potentially hazardous items which risk overturning if unrestrained. The paper concludes with a discussion on engineering for earthquake safety in buildings in a broader context than merely regulating the structural design of the building.

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Kircher, Charles A. "United States building code approach to variations in regional seismicity". Bulletin of the New Zealand Society for Earthquake Engineering 33, n. 1 (31 marzo 2000): 48–55. http://dx.doi.org/10.5459/bnzsee.33.1.48-55.

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The United States contains regions of greatly varying seismicity ranging from a relatively narrow strip of very high seismicity along coastal California in the West to broad areas of low or moderate seismicity typical of the Central and Eastern United States. The United States currently has three major regional model building codes. While all three codes have traditionally used the concept of seismic zones to identify and distinguish between regions of different seismicity, they have not had a consistent basis for their seismic criteria. Beginning in the year 2000, the three model building codes will merge and become the new International Building Code (IBC) applicable to the whole United States. New seismic design criteria have been developed for the 2000 IBC that now define ground shaking for building design by spectral acceleration contours. This paper describes the background and basis for the new seismic design criteria of the 2000 IBC, and how these criteria address the large variation in seismic hazard across the United States.

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Gouache, Corentin, Pierre Tinard e François Bonneau. "Stochastic Generator of Earthquakes for Mainland France". Applied Sciences 12, n. 2 (7 gennaio 2022): 571. http://dx.doi.org/10.3390/app12020571.

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Mainland France is characterized by low-to-moderate seismic activity, yet it is known that major earthquakes could strike this territory (e.g., Liguria in 1887 or Basel in 1356). Assessing this French seismic hazard is thus necessary in order to support building codes and to lead prevention actions towards the population. The Probabilistic Seismic Hazard Assessment (PSHA) is the classical approach used to estimate the seismic hazard. One way to apply PSHA is to generate synthetic earthquakes by propagating information from past seismicity and building various seismic scenarios. In this paper, we present an implementation of a stochastic generator of earthquakes and discuss its relevance to mimic the seismicity of low-to-moderate seismic areas. The proposed stochastic generator produces independent events (main shocks) and their correlated seismicity (only aftershocks). Main shocks are simulated first in time and magnitude considering all available data in the area, and then localized in space with the use of a probability map and regionalization. Aftershocks are simulated around main shocks by considering both the seismic moment ratio and distribution of the aftershock’s proportion. The generator is tested with mainland France data.

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Masci, F., P. Palangio e M. Di Persio. "Magnetic anomalies possibly linked to local low seismicity". Natural Hazards and Earth System Sciences 9, n. 5 (18 settembre 2009): 1567–72. http://dx.doi.org/10.5194/nhess-9-1567-2009.

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Abstract. During the last twenty years a time-synchronized network of magnetometers has operated in Central Italy along the Apennine chain to monitor the magnetic field anomalies eventually related to the tectonic activity. At present time the network consists of five stations. In the past only few anomalies in the local geomagnetic field, possibly associated to earthquakes, has been observed, not least because the network area has shown a low-moderate seismic activity with the epicentres of the few events with Ml≥5 located away from the network station. During 2007 two Ml≈4 earthquakes occurred in proximity of two stations of the network. Here we report the magnetic anomalies in the geomagnetic field that could be related with these tectonic events. To better investigate these two events a study of ULF (ultra-low-frequency) emissions has been carried out on the geomagnetic field components H, D, and Z measured in L'Aquila Observatory during the period from January 2006 to December 2008. We want to stress that this paper refers to the period before the 2009 L'Aquila seismic sequence which main shock (Ml=5.8) of 6 April heavily damaged the medieval centre of the city and surroundings. At present time the analysis of the 2009 data is in progress.

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Catalán, Ariel, Amadeo Benavent-Climent e Xavier Cahís. "Selection and scaling of earthquake records in assessment of structures in low-to-moderate seismicity zones". Soil Dynamics and Earthquake Engineering 30, n. 1-2 (gennaio 2010): 40–49. http://dx.doi.org/10.1016/j.soildyn.2009.09.003.

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Koh, Hyun-Moo, e Daegi Hahm. "Risk-based Optimum Design of Seismically Isolated Bridges in a Region of Low to Moderate Seismicity". IABSE Symposium Report 90, n. 12 (1 gennaio 2005): 77–84. http://dx.doi.org/10.2749/222137805796270388.

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Ho, Johnny Ching Ming. "Limited ductility design of reinforced concrete columns for tall buildings in low to moderate seismicity regions". Structural Design of Tall and Special Buildings 20, n. 1 (1 giugno 2010): 102–20. http://dx.doi.org/10.1002/tal.610.

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Kim, Hyun-Su, e Joo-Won Kang. "Investigation of Adaptability of Smart Top-Story Isolation System to Structures in Regions of Low-to-Moderate Seismicity". Journal of the Korean Association for Spatial Structures 12, n. 4 (15 dicembre 2012): 71–80. http://dx.doi.org/10.9712/kass.2012.12.4.071.

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Bajaj, Ketan, e P. Anbazhagan. "Regional stochastic ground-motion model for low to moderate seismicity area with variable seismotectonic: application to Peninsular India". Bulletin of Earthquake Engineering 17, n. 7 (25 maggio 2019): 3661–80. http://dx.doi.org/10.1007/s10518-019-00646-9.

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Bommer, Julian J., Kevin J. Coppersmith, Ryan T. Coppersmith, Kathryn L. Hanson, Azangi Mangongolo, Johann Neveling, Ellen M. Rathje et al. "A SSHAC Level 3 Probabilistic Seismic Hazard Analysis for a New-Build Nuclear Site in South Africa". Earthquake Spectra 31, n. 2 (maggio 2015): 661–98. http://dx.doi.org/10.1193/060913eqs145m.

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A probabilistic seismic hazard analysis has been conducted for a potential nuclear power plant site on the coast of South Africa, a country of low-to-moderate seismicity. The hazard study was conducted as a SSHAC Level 3 process, the first application of this approach outside North America. Extensive geological investigations identified five fault sources with a non-zero probability of being seismogenic. Five area sources were defined for distributed seismicity, the least active being the host zone for which the low recurrence rates for earthquakes were substantiated through investigations of historical seismicity. Empirical ground-motion prediction equations were adjusted to a horizon within the bedrock at the site using kappa values inferred from weak-motion analyses. These adjusted models were then scaled to create new equations capturing the range of epistemic uncertainty in this region with no strong motion recordings. Surface motions were obtained by convolving the bedrock motions with site amplification functions calculated using measured shear-wave velocity profiles.

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Heidebrecht, A. C. "Seismic design implications of revisions to the National Building Code of Canada". Bulletin of the New Zealand Society for Earthquake Engineering 36, n. 2 (30 giugno 2003): 108–16. http://dx.doi.org/10.5459/bnzsee.36.2.108-116.

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This paper begins with a brief introduction to Canadian seismicity and the history of seismic code development in Canada; a summary of major changes planned for the 2005 edition of the National Building Code of Canada follows. Areas of major change include seismic hazard, site effects, irregularities, force reduction factors and methods of analysis (dynamic analysis now being preferred). The implications of the proposed changes are presented in terms of impact on seismic design force for several structural systems located in regions of high, moderate and low seismicity; implications for seismic level of protection and the seismic design process are also discussed. The paper concludes with a discussion of ongoing seismic code development issues.

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Su, R. K. L., T. O. Tang e K. C. Liu. "Simplified seismic assessment of buildings using non-uniform Timoshenko beam model in low-to-moderate seismicity regions". Engineering Structures 120 (agosto 2016): 116–32. http://dx.doi.org/10.1016/j.engstruct.2016.04.006.

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Savvaidis, Alexandros, Anthony Lomax e Caroline Breton. "Induced Seismicity in the Delaware Basin, West Texas, is Caused by Hydraulic Fracturing and Wastewater Disposal". Bulletin of the Seismological Society of America 110, n. 5 (25 agosto 2020): 2225–41. http://dx.doi.org/10.1785/0120200087.

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ABSTRACT Most current seismicity in the southern U.S. midcontinent is related to oil and gas operations (O&G Ops). In Texas, although recorded earthquakes are of low-to-moderate magnitude, the rate of seismicity has been increasing since 2009. Because of the newly developed Texas Seismological Network, in most parts of Texas, recent seismicity is reported on a daily basis with a magnitude of completeness of ML 1.5. Also, funded research has allowed the collection of O&G Op information that can be associated with seismicity. Although in the Dallas–Fort Worth area, recent seismicity has been associated mostly with saltwater disposal (SWD), in the South Delaware Basin, West Texas, both hydraulic fracturing (HF) and SWD have been found to be causal factors. We have begun to establish an O&G Op database using four different sources—IHS, FracFocus, B3, and the Railroad Commission of Texas—with which we can associate recent seismicity to HF and SWD. Our approach is based on time and epicentral location of seismic events and time, location of HF, and SWD. Most seismicity occurs in areas of dense HF and SWD-well activity overlapping in time, making association of seismicity with a specific well type impossible. However, through examination of clustered seismicity in space and time, along with isolated clusters of spatiotemporal association between seismicity and O&G Ops, we are able to show that a causation between HF and seismicity may be favored over causation with SWD wells in areas of spatially isolated earthquake clusters (Toyah South, Reeves West, Jeff Davis Northeast, and Jeff Davis East). Causality between SWD and seismicity may be inferred for isolated cases in Reeves South and Grisham West.

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Franke, Kevin W., Bret N. Lingwall, T. Leslie Youd, Jenny Blonquist e Jingwen He Liang. "Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading". Soil Dynamics and Earthquake Engineering 116 (gennaio 2019): 681–91. http://dx.doi.org/10.1016/j.soildyn.2018.10.040.

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Ormeni, Rrapo, Albana Hasimi, Elvin Como, Hamza Reci, Gazmir Cela, Donald Mucaj e Olgert Gjuzi. "Analysis of Seismicity in Elbasani Geothermal Zone during Five Last Decades". European Journal of Environment and Earth Sciences 4, n. 2 (5 marzo 2023): 1–5. http://dx.doi.org/10.24018/ejgeo.2023.4.2.380.

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During the last five decades since 1968, the Elbasani zone in Albania is dominated by low seismicity. This fault zone has evidenced some seismological phenomena. It is a transversal active fault zone with normal and strike-slip faults characterized by low-velocity layers. From instrumental seismicity in this area have been located 1831 seismic events, with magnitude ML > 1.1 Richter and 3 of them with magnitude ML > 5.0. Recently on May 19, 2014, a moderate earthquake ML5.2 occurred in the Elbasani seismogenic zone. This earthquake was located 6 km southeast of Belshi town and 18 km south of Elbasani town and was felt over Albania. The analysis of seismicity during the period of time 968-2022 years indicates that most earthquakes were located in the upper and middle earth crust and very few in the uppermost mantle. The focal mechanisms solution of some earthquakes indicates an extensional regime in this fault zone. The parameters of focal mechanisms indicate the predominance of normal fault motion and strike-slip fault motion is compatible with the present-day extension regime. The Elbasan zone has a complex geological structure with a significant number of geothermal water resources and some features of seismicity. The analysis of the features of seismicity during the five last decades provides us with correct interpretations of seismotectonic, low velocity lowers and understanding of geodynamic phenomena of the Earth's crust. The area of active faults of Elbasan presents a threat to the city of Elbasan and to the curative and tourist area of Llinxha-Hidrat.

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Valenzuela-Malebrán, Carla, Simone Cesca, Sergio Ruiz, Luigi Passarelli, Felipe Leyton, Sebastian Hainzl, Bertrand Potin e Torsten Dahm. "Seismicity clusters in Central Chile: investigating the role of repeating earthquakes and swarms in a subduction region". Geophysical Journal International 224, n. 3 (21 novembre 2020): 2028–43. http://dx.doi.org/10.1093/gji/ggaa562.

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SUMMARY Seismicity along subduction interfaces is usually dominated by large main-shock–aftershock sequences indicative of a continuum distribution of highly coupled large asperities. In the past decades, however, the increased resolution of seismic catalogues at some subduction zone seems to indicate instead a more complex rheological segmentation of the interface. Large and megathrust earthquake ruptures seem interspersed among regions of low seismic coupling and less stress buildup. In this weaker zone, the strain is primarily released via a combination of moderate-size swarm-like seismicity and aseismic slip. Along the Chilean subduction zone, the densification of the seismic network allowed for the identification of localized seismic clusters, some of them appearing in the form of swarms before megathrust earthquakes. The origin and driving processes of this seismic activity have not yet been identified. In this study, we follow a systematic approach to characterize the seismicity at two persistent clusters in Central Chile, one located offshore Navidad and one inland, at ∼40 km depth beneath Vichuquén, which occurred throughout ∼20 yr. We investigated these clusters, by deriving high-resolution hypocentral locations and moment tensors and performing a detailed analysis of spatio-temporal patterns, magnitude and interevent time distributions of the clustered earthquakes. Both clusters are characterized by weak to moderate seismicity (below Mw 6) and stand out as clear seismicity rate and Benioff strain anomalies. At the Navidad cluster, seismicity occurs in the form of swarms, with a characteristic duration of 2–7 d and location and thrust mechanisms compatible with activity on the slab interface. Conversely, we find at Vichuquén activity dominated by thrust earthquakes occurring as repeaters on the slab interface, with a slip rate of approximately ∼5.0 cm yr−1. We attribute these clusters to local features of the subducting plate: the Navidad swarms are likely driven by repeated high pore pressure transients along a pre-fractured patch of the slab, while the seismicity at the Vichuquén cluster is interpreted as the result of a subducting seamount. Both clusters have been active before and after the Mw 8.8 Maule earthquake and persisted afterwards with the seismicity decay following the Omori law. These interactions are especially evident for the Vichuquén cluster, where the seismicity rate increased considerably after the Maule earthquake and continues to be an area of clearly elevated seismicity rate compared to its surroundings.

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Kechidi, Smail, Luís Macedo, José Miguel Castro e Nouredine Bourahla. "Design and Assessment of Cold-Formed Steel Shear Wall Systems Located in Moderate-to-High Seismicity Regions". Key Engineering Materials 763 (febbraio 2018): 645–52. http://dx.doi.org/10.4028/www.scientific.net/kem.763.645.

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This paper presents a numerical simulation aimed at analysing the seismic performance of low- and mid-rise cold-formed steel (CFS) framed buildings, employing wood-sheathed shear wall panels (SWPs), designed according to a seismic design procedure compatible with the framework of the Eurocodes. To simulate their nonlinear behaviour, the structures were modelled adopting a recently developed deteriorating hysteresis model. In order to study the seismic performance and determine the seismic performance factors, Incremental Dynamic Analysis of 54 archetype buildings was performed in OpenSees. The seismic performance assessment was evaluated according to the methodology defined in FEMA P695. The results indicate that a behaviour factor q equal to 2 is appropriate for CFS framed structures using wood-sheathed SWPs lateral load resisting system designed for low and moderate seismicity regions. Further, the probabilistic seismic risk assessment of the studied frames, is presented. The importance and usefulness of the risk metrics are highlighted and adopted as an indicator to explore the behavioural features of the CFS-SWP structural system. Overall, the assessment procedure showed an acceptable seismic performance and therefore the CFS-SWP can be seen as a reliable structural solution to achieve performance-based objectives even in moderate-to-high seismicity regions.

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Kim, Hyun-Su, e Joo-Won Kang. "Study of Characteristics of Smart Base Isolation System with MR Damper for Regions of Low-to-Moderate Seismicity". Journal of Korean Society of Steel Construction 24, n. 3 (27 giugno 2012): 325–36. http://dx.doi.org/10.7781/kjoss.2012.24.3.325.

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Kim, Hyun-Su, e Joo-Won Kang. "Investigation of Adaptability of Smart Base Isolation System for Spacial Structures in Regions of Low-to-Moderate Seismicity". Journal of the Korean Association for Spatial Structures 11, n. 4 (15 dicembre 2011): 109–19. http://dx.doi.org/10.9712/kass.2011.11.4.109.

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Poluraju, P., e G. Appa Rao. "Seismic Behaviour of Precast Reinforced Concrete Beam-Column Connections: A Literature Review". Applied Mechanics and Materials 343 (luglio 2013): 9–13. http://dx.doi.org/10.4028/www.scientific.net/amm.343.9.

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Precast construction is gaining importance during recent past. Most of the studies reported on precast beam-column joints are to select the appropriate connections to be adopted particularly for regions of low to moderate seismicity. This paper reports on a comprehensive review of literature on the investigations carried out to analyze and evaluate the behaviour of precast concrete structural systems assembled with typical connections or joints under simulated earthquake loading. The seismic performance of precast concrete structure very much depends on the ductility of the joints framed by precast beams and columns. It has been understood that (1) moment resistance beam-column connection and (2) ductile connectors seems to be the most widely used in the precast construction in seismic regions. Further, refinement and research could be carried out in order to optimize such connections to be recommended in low seismicity regions.

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Hsu, Ya-Ju, Honn Kao, Roland Bürgmann, Ya-Ting Lee, Hsin-Hua Huang, Yu-Fang Hsu, Yih-Min Wu e Jiancang Zhuang. "Synchronized and asynchronous modulation of seismicity by hydrological loading: A case study in Taiwan". Science Advances 7, n. 16 (aprile 2021): eabf7282. http://dx.doi.org/10.1126/sciadv.abf7282.

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Delineation of physical factors that contribute to earthquake triggering is a challenging issue in seismology. We analyze hydrological modulation of seismicity in Taiwan using groundwater level data and GNSS time series. In western Taiwan, the seismicity rate reaches peak levels in February to April and drops to its lowest values in July to September, exhibiting a direct correlation with annual water unloading. The elastic hydrological load cycle may be the primary driving mechanism for the observed synchronized modulation of earthquakes, as also evidenced by deep earthquakes in eastern Taiwan. However, shallow earthquakes in eastern Taiwan (<18 km) are anticorrelated with water unloading, which is not well explained by either hydrological loading, fluid transport, or pore pressure changes and suggests other time-dependent processes. The moderate correlation between stacked monthly trends of large historic earthquakes and present-day seismicity implies a modestly higher seismic hazard during the time of low annual hydrological loading.

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Nasir, Asma, Esther Hintersberger e Kurt Decker. "The temporal evolution of seismicity and variability of b-values along the Vienna Basin Transfer Fault System". Austrian Journal of Earth Sciences 116, n. 1 (1 gennaio 2023): 1–15. http://dx.doi.org/10.17738/ajes.2023.0001.

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Abstract The Vienna Basin Transfer Fault System (VBTFS) is the most active fault system in the region between the Eastern Alps, the western Carpathians and the Pannonian Basin. The spatial and temporal distribution of earthquakes along the fault system shows a heterogeneous pattern including a long-time decay of seismicity at the northern part of the VBTFS, which was interpreted to result from a long aftershock sequence subsequent to the 1906 Dobrá Voda earthquake (M=5.7). In this paper we investigate if other segments of the VBTFS display similar long-term declines of seismicity that might indicate long aftershock sequences following strong, yet unrecorded, earthquakes in historical times. In order to analyse the distribution of seismicity, the VBTFS is divided into arbitrary segments of about 50 km length each. The segments are chosen to overlap each other to avoid missing information from neighbouring segments due to arbitrarily selected segment boundaries. For each segment we analyse the temporal evolution of seismicity and calculate the parameters of the corresponding Gutenberg-Richter (GR) relation. The temporal seismicity patterns revealed from the segments covering the Dobrá Voda area confirm the protracted aftershock sequence following the 1906 earthquake. All but one of the other segments do not show temporal changes of seismicity comparable to the long-term Dobrá Voda aftershock sequence. Seismicity patterns, however, include short-term Omori-type aftershocks following moderate earthquakes such as the 2000 Ebreichsdorf earthquake (M=4.8). The segment covering the SW tip of the VBTFS revealed a 200 years long gradual decrease of the largest observed magnitudes starting with the 1794 Leoben (M=4.7) earthquake. The 1794 event is the oldest earthquake listed in the catalogue for the region under consideration. It therefore remains open if the recorded decay of seismicity results from the 1794 event, or a stronger earthquake before that time. The latter is corroborated by the low magnitude of the 1794 earthquake which would typically not be considered to cause long aftershock sequences. GR a- and b-values, calculated for the individual segments, vary significantly along the VBTFS. Values range from 0.47 to 0.86 (b-values) and 0.81 to 2.54 (a-values), respectively. Data show a significant positive correlation of a- and b-values and a coincidence of the lowest b-values with fault segments with large seismic slip deficits and very low seismicity in the last approximately 300 years. These parts of the VBTFS were previously interpreted as “locked” fault segments, which have a significant potential to release future strong earthquakes, in spite of the fact that historical and instrumentally recorded seismicity is very low. We find this interpretation corroborated by the low b-values that suggest high differential stresses for these fault segments.

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Kumar, Susheel, e Nitin Sharma. "The seismicity of central and north-east Himalayan region". Contributions to Geophysics and Geodesy 49, n. 3 (1 settembre 2019): 265–81. http://dx.doi.org/10.2478/congeo-2019-0014.

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Abstract The Himalayan range extends upto 2400 km arc from Indus river valley in the west to Brahmaputra river valley in the east of India. Due to distinct geological structures of Himalayan seismic belt, seismicity in Himalaya is inhomogeneous. The inhomogeneity in seismicity is responsible for a number of seismic gaps in the Himalayan seismic belt. Thus Iin the present study, we proposed the study of spatial and temporal evolution of seismicity in entire central and north-east Himalayan region by using Gutenberg-Richter relationship. A detailed study on the behavior of natural seismicity in and around the seismic gap regions is carried out. The study region is segmented in four meridional regions (A) 80°E to 83.5°E, (B) 83.5°E to 87.5°E, (C) 87.5°E to 90°E and (D) 90°E to 98°E along with a fixed latitude belt. The homogeneous catalogue with 3 ≤ Mb ≤ 6.5 is used for the spatial and temporal analysis of seismicity in terms of b-value. It is find out that pockets of lower b-values are coinciding over and around stress accumulated regions. The observed low b-value before occurrence of the Nepal earthquake of 25th April, 2015 supports the argument of impending occurrence of moderate to large magnitude earthquake in Sikkim and north-east Himalayan region in future.

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Hofman, Laurens Jan, Jörn Kummerow e Simone Cesca. "A new seismicity catalogue of the eastern Alps using the temporary Swath-D network". Solid Earth 14, n. 10 (10 ottobre 2023): 1053–66. http://dx.doi.org/10.5194/se-14-1053-2023.

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Abstract. We present a new, consistently processed seismicity catalogue for the eastern and southern Alps based on the temporary dense Swath-D monitoring network. The final catalogue contains 6053 earthquakes for the time period 2017–2019 and has a magnitude of completeness of −1.0 ML. The smallest detected and located events have a magnitude of −1.7 ML. Aimed at the low to moderate seismicity in the study region, we have developed a multi-stage, mostly automatic workflow that combines a priori information from local catalogues and waveform-based event detection, subsequent efficient GPU-based (GPU: graphics processing unit) event search by template matching, P and S arrival time pick refinement, and location in a regional 3-D velocity model. The resulting seismicity distribution generally confirms the previously identified main seismically active domains but provides increased resolution of the fault activity at depth. In particular, the high number of small events additionally detected by the template search contributes to a denser catalogue and provides an important basis for future geological and tectonic studies in this complex part of the Alpine orogen.

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Perron, Vincent, Fabrice Hollender, Pierre‐Yves Bard, Céline Gélis, Cédric Guyonnet‐Benaize, Bruno Hernandez e Olga‐Joan Ktenidou. "Robustness of Kappa (κ) Measurement in Low‐to‐Moderate Seismicity Areas: Insight from a Site‐Specific Study in Provence, France". Bulletin of the Seismological Society of America 107, n. 5 (25 settembre 2017): 2272–92. http://dx.doi.org/10.1785/0120160374.

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Kim, Hyun-Su, e Joo-Won Kang. "Study of Integrated Optimal Design of Smart Top-Story Isolation and Building Structures in Regions of Low-to-Moderate Seismicity". Journal of the Korea institute for structural maintenance and inspection 17, n. 5 (30 settembre 2013): 13–20. http://dx.doi.org/10.11112/jksmi.2013.17.5.013.

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Caruso-Juliano, A., A. Gallagher, T. E. Morrison e C. A. Rogers. "Seismic performance of single-storey steel concentrically braced frame structures constructed in the 1960s". Canadian Journal of Civil Engineering 41, n. 7 (luglio 2014): 579–93. http://dx.doi.org/10.1139/cjce-2013-0198.

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A general overview of the seismic performance of representative single-storey concentrically braced frame (CBF) buildings designed using the 1965 National Building Code of Canada and the 1965 S16 Canadian Standards Association Steel Structures for Buildings Standard was obtained through the use of nonlinear time history dynamic analyses and the testing of brace elements obtained from buildings constructed in the 1960s. The study comprised 16 representative buildings subjected to 20 site selected ground motions for three locations; Halifax (Nova Scotia) low seismicity, Montreal (Quebec) moderate seismicity, and Abbotsford (British Columbia) high seismicity. Incremental dynamic analyses were performed using various failure criteria as obtained from the test data; brace net-section fracture, bolt shear, block shear, bolt bearing and brace yielding. Fragility curves were created and the probability of failure was defined. The performance of the structures designed for Abbotsford was unsatisfactory for all of the brace connection failure mechanisms. In contrast, because of the lower current seismic hazard in Montreal, the 16 archetypical buildings demonstrated better performance. In Halifax the buildings performed well, based on the identified failure criteria. It was necessary to strengthen the roof diaphragms for all buildings to carry 2010 NBCC design level seismic forces.

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Shin, Dong-Hyeon, e Hyung-Joon Kim. "Influence of the lateral restoring force of isolation system to the seismic performance of isolated buildings in low-to-moderate seismicity regions". Soil Dynamics and Earthquake Engineering 125 (ottobre 2019): 105706. http://dx.doi.org/10.1016/j.soildyn.2019.105706.

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Watters, T. R., N. C. Schmerr, R. C. Weber, C. L. Johnson, E. J. Speyerer, M. S. Robinson e M. E. Banks. "Tectonics and Seismicity of the Lunar South Polar Region". Planetary Science Journal 5, n. 1 (1 gennaio 2024): 22. http://dx.doi.org/10.3847/psj/ad1332.

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Abstract The lunar south pole regions are subjected to global stresses that result in contractional deformation and associated seismicity. This deformation is mainly expressed by lobate thrust fault scarps; examples are globally distributed, including polar regions. One small cluster of lobate scarps falls within the de Gerlache Rim 2 Artemis III candidate landing region. The formation of the largest de Gerlache scarp, less than 60 km from the pole, may have been the source of one of the strongest shallow moonquakes recorded by the Apollo Passive Seismic Network. The scarp is within a probabilistic space of relocated epicenters for this event determined in a previous study. Modeling suggests that a shallow moonquake with an M w of ∼5.3 may have formed the lobate thrust fault scarp. We modeled the peak ground acceleration generated by such an event and found that strong to moderate ground shaking is predicted at a distance from the source of at least ∼40 km, while moderate to light shaking may extend beyond ∼50 km. Models of the slope stability in the south polar region predict that most of the steep slopes in Shackleton crater are susceptible to regolith landslides. Light seismic shaking may be all that is necessary to trigger regolith landslides, particularly if the regolith has low cohesion (on the order of ∼0.1 kPa). The potential of strong seismic events from active thrust faults should be considered when preparing and locating permanent outposts and pose a possible hazard to future robotic and human exploration of the south polar region.

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Duverger, Clara, Gilles Mazet-Roux, Laurent Bollinger, Aurélie Guilhem Trilla, Amaury Vallage, Bruno Hernandez e Yves Cansi. "A decade of seismicity in metropolitan France (2010–2019): the CEA/LDG methodologies and observations". BSGF - Earth Sciences Bulletin 192 (2021): 25. http://dx.doi.org/10.1051/bsgf/2021014.

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We summarize ten years of the French seismicity recorded by the Geophysical and Detection Laboratory (LDG) of the French Alternative Energies and Atomic Energy Commission (CEA) network from 2010 to 2019. During this period, 25 265 natural earthquakes were detected by the LDG and located within metropolitan France and its immediate vicinity. This seismicity contributes to more than 47% of the natural earthquakes instrumentally recorded since 1962 (mainly due to the improvement of network capacity), and includes about 28% of the most significant earthquakes with a magnitude ML ≥ 4.0. Recent seismic events therefore significantly expand the available national catalogues. The spatial distribution of 2010–2019 earthquakes is broadly similar to the previously recorded instrumental pattern of seismicity, with most of the seismic activity concentrated in the French Alps, the Pyrenees, Brittany, the upper Rhine Graben and the Central Massif. A large part of the seismic activity is related to individual events. The largest earthquakes of the last ten years include the November 11, 2019 Le Teil earthquake with ML 5.4 and epicentral intensity VII–VIII, which occurred in the Rhone valley; the April 28, 2016 La Rochelle earthquake with ML 5.1 and epicentral intensity V, which occurred at the southernmost extremity of the Armorican Massif in the vicinity of the Oléron island; and the April 7, 2014 Barcelonnette earthquake with ML 5.1 and epicentral intensity V–VI, which occurred in the Ubaye valley in the Alps. In 2019, two other moderate earthquakes of ML 5.1 and ML 4.9 stroke the western part of France, in Charente-Maritime and Maine-et-Loire departments, respectively. The recent moderate earthquake occurrences and the large number of small earthquakes recorded give both the potential to revise some regional historical events and to determine more robust frequency-magnitude distributions, which are critical for seismic hazard assessment but complex due to low seismicity rates in France. The LDG seismic network installed since the early 1960s also allows a better characterization of the temporal structure of seismicity, partly diffused and in the form of mainshock-aftershocks sequences or transient swarms. These aspects are important in order to lower the uncertainties associated to seismogenic sources and improve the models in seismic hazard assessment for metropolitan France.

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Carmona, Enrique, Javier Almendros, Inmaculada Serrano, Daniel Stich e Jesús M. Ibáñez. "Results of seismic monitoring surveys of Deception Island volcano, Antarctica, from 1999–2011". Antarctic Science 24, n. 5 (17 maggio 2012): 485–99. http://dx.doi.org/10.1017/s0954102012000314.

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AbstractDeception Island volcano (South Shetland Islands, Antarctica) has been monitored in summer surveys since 1994. We analyse the seismicity recorded from 1999–2011 with a local network and seismic arrays. It includes long-period (LP) events, volcanic tremor episodes and volcano-tectonic (VT) earthquakes. Long-period events are conspicuous, ranging from 58 (2007–08) to 2868 events (2003–04). The highest number of LP events in one day is 243 on 2 February 2001, and there are several discrete periods of intense LP activity. These variations may be related to alterations in the shallow hydrothermal system of Deception Island. The number of VT earthquakes recorded during the surveys range from 4 (2008–09) to 125 (2007–08). In some periods VT distributions are temporally and spatially homogeneous, with a generally low level of seismicity. In other periods we observe a peak of VT activity lasting a few days, concentrated in a particular area. These two patterns may respond to different processes, involving regional stresses and local tectonic destabilization induced by volcanic activity. Overall, this study indicates that over the period 1999–2011 the volcano presented a moderate level of seismicity, and suggests that there has been no significant reactivation of the volcano since the 1999 seismic crisis.

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Hasegawa, H. S. "Seismogenesis in Eastern Canada". Seismological Research Letters 59, n. 4 (1 ottobre 1988): 219–25. http://dx.doi.org/10.1785/gssrl.59.4.219.

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Abstract The pattern of seismicity in eastern Canada depends on the presence of weak zones from previous major tectonic orogenies and how these weak zones are reactivated by local and regional stress fields and geophysical processes. Within the Canadian Shield, away from seismotectonic trends, there is a low level of seismicity and earthquakes tend to be small, less than M5. However, along seismically active trends, earthquakes as large as M7 have occurred. The seismotectonic features fall into four main categories: positive (uplift) continental basement linears; grabens formed by old plate separation; passive rifted margins offshore; and extinct spreading ridges. Two of the positive seismotectonic trends are the Boothia Uplift-Bell Arch that transects the northeastern part of the craton and northeastern Baffin Island, where the effects of postglacial rebound on the upper crustal stress field are the most pronounced. The St. Lawrence Valley (and interconnecting grabens) is a seismically active graben system that contains the most seismically active region (the Charlevoix zone) in eastern Canada. The extinct spreading ridge along the Labrador Sea and the Mesozoic rifted margin along Baffin Bay and Labrador Sea contain clusters of moderate seismicity. There are diffuse zones of moderate seismicity over some geological provinces (e.g. Central Metasedimentary Belt in western Quebec) apart from major tectonic features, a confined seismic zone (within an intrusion) in the Miramichi region and seismicity at the intersection of faults in northern Ontario. In the Nahanni region, which is situated near the boundary between the northeast Cordillera and the Interior Platform, the commencement of a noteworthy earthquake sequence with magnitude up to Ms 6.9 indicates considerable stress-strain build-up over a large area. There is an anticline in the epicentral area that is bounded by thrust faults and mountain ranges. In order to enhance our understanding of causative factors of current seismicity, it is necessary to determine in greater detail the tectonic forces and geophysical processes that are reactivating pre-weakened faults along the seismotectonic trends and over broad, diffuse seismogenic regions. Some of these factors are the rate of stress build-up, stress concentration at the intersection of faults and between mountain ranges, residual stress, the role of pore fluids, individual block movement, whether this movement is due to postglacial rebound or to other underlying viscoelastic phenomena and the rate of sediment deposition along the continental slope. Paleoseismicity is useful not only for the reconstruction of old large earthquakes but also for providing insight as to why surface fault offsets have not been observed in regions where large earthquakes (and associated high rate of microseisrnicity) have occurred within the past several hundred years.

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Ho, Johnny Ching-Ming, e Kevin Jian-Hui Zhou. "LIMITED DEFORMABILITY DESIGN OF HIGH-STRENGTH CONCRETE BEAMS IN LOW TO MODERATE SEISMICITY REGIONS / STIPRIOJO BETONO SIJŲ RIBINIO DEFORMATYVUMO SKAIČIAVIMAS ŽEMO IR VIDUTINIO SEISMINGUMO REGIONUOSE". Journal of Civil Engineering and Management 17, n. 3 (20 settembre 2011): 409–23. http://dx.doi.org/10.3846/13923730.2011.594219.

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In the design of reinforced concrete (RC) beams located in low-moderate seismicity regions, adequate flexural deformability apart from flexural strength to cater for the imposed seismic demand should be designed. As per the existing RC design codes, this is achieved by restricting the maximum neutral axis depth or tension steel ratio, or limiting the minimum confining steel. However, these deemed-to-satisfy rules were derived many years ago based on normal-strength concrete and steel, which would impair the deformability when applied directly to RC beams made of high-strength materials. To resolve the problem, a new design method based on a prescribed deformability is advocated. In this study, the authors proposed that instead of complying with the deemed-to-satisfy rules, a consistent deformability derived based on the design requirements of Eurocode 2 should be provided to all RC beams located in low-moderate seismicity regions. Using the theoretical formulas developed previously by the authors, two different sets of design values expressed in terms of maximum tension steel ratio and neutral axis to beam effective depths for different concrete and steel yield strengths are evaluated. Finally, simplified guidelines for designing RC beams satisfying the proposed deformability requirement are developed for practical design application. Santrauka Mažo ir vidutinio seismingumo regionuose projektuojant seisminių apkrovų veikiamas gelžbetonines sijas turi būti užtikrinta ne tik jų laikomoji galia, bet ir tinkamas deformatyvumas. Pagal šiuo metu galiojančias gelžbetoninių konstrukcijų projektavimo normas tai pasiekiama ribojant didžiausiąjį skerspjūvio aukštį, tempiamosios zonos armavimo procentą arba ribojant mažiausią armatūros kiekį. Tačiau šios konstravimo taisyklės buvo sukurtos prieš daugelį metų ir skirtos elementams iš normalaus stiprio betono ir armatūros. Jas tiesiogiai taikant gelžbetoninėms sijoms, pagamintoms iš stipriųjų medžiagų, gaunamas sumažintos deformacijos. Šiais problemai spręsti siūlomas naujas projektavimo metodas, paremtas nustatytu deformatyvumu. Autoriai siūlo mažo ir vidutinio seismingumo regionuose visas gelžbetonines sijas projektuoti pasirenkant deformacijas pagal ”Eurokode 2“ pateiktus deformatyvumo reikalavimus. Pagal anksčiau autorių gautas teorines formules skirtingiems betono ir plieno stipriams pateiktos dvi atskiros skaičiuojamųjų rodiklių grupės išreikštos maksimaliu tempiamosios zonos armavimo koeficientu ir efektyviuoju sijos skerspjūvio aukščiu. Praktiniam taikymui sukurtos supaprastintos gelžbetoninių sijų projektavimo rekomendacijos, atitinkančios deformatyvumo reikalavimus.

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Douglas, John, e Alireza Azarbakht. "Cost–benefit analyses to assess the potential of Operational Earthquake Forecasting prior to a mainshock in Europe". Natural Hazards 105, n. 1 (16 settembre 2020): 293–311. http://dx.doi.org/10.1007/s11069-020-04310-3.

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AbstractIn the past couple of decades, Operational Earthquake Forecasting (OEF) has been proposed as a way of mitigating earthquake risk. In particular, it has the potential to reduce human losses (injuries and deaths) by triggering actions such as reinforcing earthquake drills and preventing access to vulnerable structures during a period of increased seismic hazard. Despite the dramatic increases in seismic hazard in the immediate period before a mainshock (of up to 1000 times has been observed), the probability of a potentially damaging earthquake occurring in the coming days or weeks remains small (generally less than 5%). Therefore, it is necessary to balance the definite cost of taking an action against the uncertain chance that it will mitigate earthquake losses. In this article, parametric cost–benefit analyses using a recent seismic hazard model for Europe and a wide range of inputs are conducted to assess when potential actions for short-term OEF are cost–beneficial prior to a severe mainshock. Ninety-six maps for various combinations of input parameters are presented. These maps show that low-cost actions (costing less than 1% of the mitigated losses) are cost–beneficial within the context of OEF for areas of moderate to high seismicity in the Mediterranean region. The actions triggered by OEF in northern areas of the continent are, however, unlikely to be cost–beneficial unless very large increases in seismicity are observed or very low-cost actions are possible.

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Gouache, C., F. Bonneau, P. Tinard e J. M. Montel. "Estimation of main shock frequency–magnitude distributions by adapting the inter-event time method for low-to-moderate seismicity areas: application to French mainland". Journal of Seismology 25, n. 3 (23 marzo 2021): 771–82. http://dx.doi.org/10.1007/s10950-021-10001-8.

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Zamba, I., e V. Kouskouna. "Seismic history of Pel la and the 1st century B.C. earthquake". Bulletin of the Geological Society of Greece 40, n. 3 (5 giugno 2018): 1318. http://dx.doi.org/10.12681/bgsg.16883.

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Research and evaluation of past and recent seismic records is required in order to obtain an overall picture of the seismic history of a given region. To this aim, important information can be collected through the study of monuments and the damage that they may have experienced during their history. Consequently, the archaeological reports on a hitherto unknown earthquake of the Is' century B.C. in Pella (northern Greece) are particularly interesting. These reports are based on the findings that came to light after the excavations of I.Akamatis in the region where the ancient town of Pella was laying. Beginning with this earthquake, this study tries to reach useful conclusions on the seismicity of Pella, in terms of macroseismic intensities from all earthquakes that have affected the town. For all these events, the intensity attenuation relations were used to calculate the macroseismic intensity in Pella. Although it is known a priori that the area is characterized as a relatively low seismicity area, the picture of its seismic history indicates the existence of damaging earthquakes with relatively large return periods. More specifically, in Pella the maximum observed intensity was found to be 7/8 during its seismic history, indicating the picture of low-to-moderate seismic hazard in the region.

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Martin, Stacey Servito, Yu Wang, Muzli Muzli e Shengji Wei. "The 1922 Peninsula Malaysia Earthquakes: Rare Intraplate Seismicity within the Sundaland Block in Southeast Asia". Seismological Research Letters 91, n. 5 (27 maggio 2020): 2531–45. http://dx.doi.org/10.1785/0220200052.

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Abstract Seismic hazard in the southern Malay Peninsula located within the Sundaland block in Southeast Asia is poorly understood. The paucity of historical earthquakes and low-magnitude instrumented seismicity has led to the assumption that this region is largely aseismic. We question this point of view by reassessing historical seismicity in this region and, in particular, a pair of moderate earthquakes in the 1920s. The first of these struck on 31 January 1922 at ≈9:10 a.m. local time (LT) for which we estimate an intensity magnitude (MI) ≈5.4, and for the second earthquake on 7 February 1922 at ≈12:15 p.m. LT, we estimate MI≈5.0. We also identify at least 34 felt earthquakes between 1803 and 1950 that were potentially local within the Sundaland block. These include a very widely felt shock (or set of shocks) on 26 June 1874 that was felt in parts of Borneo, Java, and Sumatra. The discovery of these earthquakes challenges the tectonic stability of the Malay Peninsula and the stable interior of the Sundaland block. The record of historical seismicity in this region relies heavily on European sources, and we recommend locating and consulting indigenous sources to improve the current understanding of regional seismic hazard. We also underscore the need to evaluate the impact of ground motions from rare local earthquakes on the extant building stock and on transportation infrastructure that are otherwise relatively immune to the long-period effects of distant earthquakes commonly felt in the Malay Peninsula.

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Irinyemi, Stephen A., Domenico Lombardi e Syed M. Ahmad. "Seismic risk analysis for large dams in West Coast basin, southern Ghana". Journal of Seismology 26, n. 1 (29 settembre 2021): 101–16. http://dx.doi.org/10.1007/s10950-021-10045-w.

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AbstractDams are parts of the critical infrastructure of any nation, the failure of which would have a high-risk potential on the people and properties within the dam vicinity. Ghana is one of the most seismically active regions in West Africa and has at least 5 large dams across the region, constructed in strategic locations. The area is characterised by low-to-moderate seismicity, yet historical events suggest that major earthquakes that are potentially damaging have occurred in the study basin. This paper summarises the method used to analyse seismic risk and discusses the seismic hazards of three large dams across the study basin based on the seismicity at the dam sites and their risk due to structural properties and the location of each dam. The peak ground acceleration (PGA) values for the dam sites estimated are within the range of (0.31 g and 0.52 g) for 10,000 years return period. The study shows that one large dam has a high-risk class in the basin. This dam should be inspected and analysed for its seismic safety and people’s protection in the downstream paths.

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