Journal articles: 'Tohoku-Oki earthquakes'

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Nishikawa, T., T. Matsuzawa, K. Ohta, N. Uchida, T. Nishimura, and S. Ide. "The slow earthquake spectrum in the Japan Trench illuminated by the S-net seafloor observatories." Science 365, no. 6455 (August 22, 2019): 808–13. http://dx.doi.org/10.1126/science.aax5618.

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Investigating slow earthquake activity in subduction zones provides insight into the slip behavior of megathrusts, which can provide important clues about the rupture extent of future great earthquakes. Using the S-net ocean-bottom seismograph network along the Japan Trench, we mapped a detailed distribution of tectonic tremors, which coincided with very-low-frequency earthquakes and a slow slip event. Compiling these and other related observations, including repeating earthquakes and earthquake swarms, we found that the slow earthquake distribution is complementary to the Tohoku-Oki earthquake rupture. We used our observations to divide the megathrust in the Japan Trench into three along-strike segments characterized by different slip behaviors. We found that the rupture of the Tohoku-Oki earthquake, which nucleated in the central segment, was terminated by the two adjacent segments.

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Du, Cunpeng, Haitao Yin, Shengwen Yu, Le Yang, and Yuan Jia. "Effects of the 2011 Mw 9.0 Tohoku-Oki Earthquake on the Locking Characteristics and Seismic Risk of the Yishu Fault Zone in China." Sustainability 15, no. 5 (February 28, 2023): 4321. http://dx.doi.org/10.3390/su15054321.

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To ascertain the 2011 Tohoku-Oki Mw 9.0 earthquake’s impact on the stability of the Yishu fault zone, this study inverts the fault locking degree and slip rate defect distribution of the Yishu fault zone using GPS horizontal velocity field data covering the period from 1999 to 2009 and from April 2011 to 2019. This is based on the block negative dislocation model. Combined with the b value and strain field characteristics, the properties of deformation of the Yishu fault zone before and after the earthquake are comprehensively analyzed. The results show that before the 2011 Tohoku-Oki Mw 9.0 earthquake, the locking degree and depth of the northern segment of the Yishu fault zone were higher, while the locking depth of the southern segment of the fault was shallower. The 2011 Tohoku-Oki earthquake produced different coseismic effects on the southern and northern sections of the Yishu fault zone. The extension on the southern section and compression on the northern section caused the strain release in the southern sections of the Yishu fault zone following the earthquake. After it, the regional locking degree of the southern section of the Yishu fault zone was relieved. However, the locking degree of the northern segment of the fault zone was still high and the depth was deep, at about 26 km. In addition, the northern section of the Yishu fault zone was a section with an abnormally low b value and small earthquakes in the northern segment are sparse at present. The coseismic compression of the northern section caused by the 2011 Tohoku-Oki earthquake is conducive to its locking and easily accumulates stress, so it is necessary to pay attention to its seismic risk.

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Okawa, Izuru, Toshihide Kashima, Shin Koyama, and Masanori Iiba. "Recorded Responses of Building Structures during the 2011 Tohoku-Oki Earthquake with Some Implications for Design Practice." Earthquake Spectra 29, no. 1_suppl (March 2013): 245–64. http://dx.doi.org/10.1193/1.4000130.

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During the 2011 Tohoku-oki earthquake, a large number of response records from various types of buildings were obtained. The records give us the actual motions of buildings during the exceptionally large earthquakes that are considered comparable with design earthquakes. Various types of earthquake response records have been collected, and their properties with several buildings that will exhibit implications for structural design are discussed.

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Tao, Zheng Ru, Xia Xin Tao, and Wei Jiang. "A Review on Long-Term Evaluation of Occurrence Probability for Subduction-Zone Earthquakes in Eastern Japan." Applied Mechanics and Materials 166-169 (May 2012): 2190–96. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2190.

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Evaluation approach of occurrence probability for subduction-zone earthquakes adopted in “National Seismic Hazard Maps for Japan” is reviewed, especially for the area of the 2011 off the Pacific coast of Tohoku Earthquake (2011 Tohoku Earthquake in short). One problem is pointed that the occurrence probability of such a large earthquake cannot be predicted just from seismicity in a region small like Miyagi-ken-Oki area or southern Sanriku-Oki. The whole subduction zone in eastern Japan is suggested to be taken into account with the interaction between the energy released in quakes. Finally, a simple test to predict the next large earthquake in the subduction-zone by means of Artificial Neural Network is presented, and the result for the years of 2008-2018 shows there may be an earthquake with magnitude up to 8.8 in the zone.

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Suito, Hisashi. "Current Status of Postseismic Deformation Following the 2011 Tohoku-Oki Earthquake." Journal of Disaster Research 13, no. 3 (June 1, 2018): 503–10. http://dx.doi.org/10.20965/jdr.2018.p0503.

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Postseismic deformation following the 2011 Tohoku-Oki earthquake has been observed by the Global Navigation Satellite System (GNSS) Earth Observation Network System (GEONET) and the Seafloor Geodetic Observation (SGO) over the past six and half years. Observed deformation at onshore sites exceeds 140 cm horizontally, there is uplift of 50 cm, and deformation tends eastward. However, offshore sites reveal complex patterns ranging from near-zero deformation in the northern part of Iwate-Oki, to westward in the southern part of Iwate-Oki, Miyagi-Oki, and the northern part of Fukushima-Oki regions, and eastward in the southern part of Fukushima-Oki and Ibaraki-Oki regions, respectively. The vertical deformation pattern is more complex than the horizontal. Offshore sites demonstrate subsidence but a large uplift is observed onshore along the Pacific coast. Subsidence is only observed along the Pacific coast in the northern part of Iwate, where there are variations in uplift or subsidence patterns. Many previous 2011 Tohoku-Oki event studies have used a primary model that considers only the afterslip effect. However, westward displacements observed by the SGO highlight the importance of viscoelastic relaxation, even during short-term deformation. It is thus considered that studies on postseismic deformation following the 2011 Tohoku-Oki earthquake should adopt a combined afterslip and viscoelastic model. Postseismic deformation following this event is estimated to continue for more than a few decades; therefore, assessing this effect is crucial for interpreting crustal deformation in Japan. Information on the status of interplate coupling or slip is also vital when assessing earthquake occurrence probability. The continued observation of postseismic deformation and careful monitoring of temporal and spatial changes in interplate coupling or slip will mitigate hazards from successive large megathrust earthquakes and improve understanding of crustal activity in Japan.

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Tong, P., D. Zhao, and D. Yang. "Tomography of the 2011 Iwaki earthquake (M 7.0) and Fukushima nuclear power plant area." Solid Earth Discussions 3, no. 2 (December 22, 2011): 1021–36. http://dx.doi.org/10.5194/sed-3-1021-2011.

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Abstract. High resolution tomographic images of the crust and upper mantle in and around the area of the 2011 Iwaki earthquake (M 7.0) and the Fukushima nuclear power plant are determined by inverting a large number of high-quality arrival times with both the finite-frequency and ray tomography methods. The Iwaki earthquake and its aftershocks mainly occurred in a boundary zone with strong variations in seismic velocity and Poisson's ratio. Prominent low-velocity and high Poisson's ratio zones are revealed under the Iwaki source area and the Fukushima nuclear power plant, which may reflect fluids released from the dehydration of the subducting Pacific slab under Northeast Japan. The 2011 Tohoku-oki earthquake (Mw 9.0) caused static stress transfer in the overriding Okhotsk plate, resulting in the seismicity in the Iwaki source area that significantly increased immediately following the Tohoku-oki mainshock. Our results suggest that the Iwaki earthquake was triggered by the ascending fluids from the Pacific slab dehydration and the stress variation induced by the Tohoku-oki mainshock. The similar structures under the Iwaki source area and the Fukushima nuclear power plant suggest that the security of the nuclear power plant site should be strengthened to withstand potential large earthquakes in the future.

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Tong, P., D. Zhao, and D. Yang. "Tomography of the 2011 Iwaki earthquake (M 7.0) and Fukushima nuclear power plant area." Solid Earth 3, no. 1 (February 14, 2012): 43–51. http://dx.doi.org/10.5194/se-3-43-2012.

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Abstract. High-resolution tomographic images of the crust and upper mantle in and around the area of the 2011 Iwaki earthquake (M 7.0) and the Fukushima nuclear power plant are determined by inverting a large number of high-quality arrival times with both the finite-frequency and ray tomography methods. The Iwaki earthquake and its aftershocks mainly occurred in a boundary zone with strong variations in seismic velocity and Poisson's ratio. Prominent low-velocity and high Poisson's ratio zones are revealed under the Iwaki source area and the Fukushima nuclear power plant, which may reflect fluids released from the dehydration of the subducting Pacific slab under Northeast Japan. The 2011 Tohoku-oki earthquake (Mw 9.0) caused static stress transfer in the overriding Okhotsk plate, resulting in the seismicity in the Iwaki source area that significantly increased immediately following the Tohoku-oki mainshock. Our results suggest that the Iwaki earthquake was triggered by the ascending fluids from the Pacific slab dehydration and the stress variation induced by the Tohoku-oki mainshock. The similar structures under the Iwaki source area and the Fukushima nuclear power plant suggest that the security of the nuclear power plant site should be strengthened to withstand potential large earthquakes in the future.

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Kasai, Kazuhiko, Akira Mita, Haruyuki Kitamura, Kazuhiro Matsuda, Troy A. Morgan, and Andrew W. Taylor. "Performance of Seismic Protection Technologies during the 2011 Tohoku-Oki Earthquake." Earthquake Spectra 29, no. 1_suppl (March 2013): 265–93. http://dx.doi.org/10.1193/1.4000131.

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Many buildings in the Tohoku and Kanto area were strongly shaken during the Tohoku-oki earthquake on 11 March 2011. Soon after the earthquake, the Japan Society of Seismic Isolation (JSSI) established committees to investigate the performance of structures where modern seismic protection methods were used. Since response-control technologies are relatively new, few systems had been validated with actual earthquakes. Generally, the various buildings performed well, and there were no failures of superstructures of base-isolated or supplementally damped buildings. Failures of numerous expansion joints and lead dampers in base-isolated buildings are described. Acceleration records of both base-isolated and supplementally damped buildings are analyzed and their seismic performance characteristics are discussed.

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9

Shibazaki, Bunichiro, and Hiroyuki Noda. "What Caused the 2011 Tohoku-Oki Earthquake? : Effects of Dynamic Weakening." Journal of Disaster Research 9, no. 3 (June 1, 2014): 252–63. http://dx.doi.org/10.20965/jdr.2014.p0252.

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Some observational studies have suggested that the 2011 great Tohoku-Oki earthquake (Mw9.0) released a large portion of the accumulated elastic strain on the plate interface owing to considerable weakening of the fault. Recent experimental and theoretical studies have shown that considerable dynamic weakening can occur at high slip velocities because of thermal pressurization or thermal weakening processes. This paper reviews severalmodels of the generation of megathrust earthquakes along the Japan Trench subduction zone, that considers thermal pressurization or a friction law that exhibits velocity weakening at high slip velocities, and it discusses the causes of megathrust earthquakes. To reproduce megathrust earthquakes with recurrence intervals of several hundreds of years, it will be necessary to consider the existence of a region at the shallow subduction plate boundary where significant dynamic weakening occurs due to thermal pressurization or other thermal weakening processes.

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Hashimoto, Manabu. "Crustal Deformation Associated with the 2011 Tohoku-Oki Earthquake: An Overview." Earthquake Spectra 29, no. 1_suppl (March 2013): 81–98. http://dx.doi.org/10.1193/1.4000117.

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The 2011 Tohoku-oki earthquake generated large displacements in and around the Japanese islands that were detected by the nationwide GPS network, sea-floor geodetic surveys, and space-borne radars. The east-west extension exerted on the Japanese islands by this event induced inland events of Mw6 or larger earthquakes. Coseismic subsidence of up to 1 m was observed along the coast where subsidence was found during the interseismic period. This observation contradicts expectations based on the concept of the recurrence of inter-plate earthquakes. Therefore, postseismic motions or other large events are expected to resolve this paradox.

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Anderson, John G. "Surface Motions on Near-Distance Rock Sites in the 2011 Tohoku-Oki Earthquake." Earthquake Spectra 29, no. 1_suppl (March 2013): 23–35. http://dx.doi.org/10.1193/1.4000111.

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This paper selects several sites intended to represent relatively undistorted rock motions just inland from the faulting in the 2011 Tohoku-oki earthquake. Sites were selected for relatively high values of VS30 and for absence of strong site resonances. At these sites, ground motions at the surface were moderate, with peak accelerations of up to ∼330 cm/s2 and peak velocities up to ∼45 cm/s. Although moderate, these records imply that the strong motion generating area of the Tohoku earthquake was as much as ten times more energetic than the 1985 Michoacan earthquake, for which ground motions on rock were recorded above a strong motion generating area. These results suggest that a wide range of source parameters can occur in subduction zone earthquakes.

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12

Kato, Aitaro. "Slow Slip Transients Before the 2011 Tohoku-Oki Earthquake." Journal of Disaster Research 9, no. 3 (June 1, 2014): 311–16. http://dx.doi.org/10.20965/jdr.2014.p0311.

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I review a spatiotemporal evolution of slow-slip transients on the plate interface of the subducting Pacific plate that happened in and around the mainshock rupture area prior to the 2011 Tohoku-Oki earthquake. Based on foreshock activity before the mainshock, two sequences of slow-slip transients were identified by earthquake migrations toward the initiation point of the mainshock rupture. These two slow-slip transients were also detected by geodetic measurement. The second sequence of slow-slip transients, which involved large slip rates, may have caused significant stress loading onto the hypocenter of the mainshock and prompted the initiation of unstable dynamic rupture. In addition, decadal slip-behavior on the plate interface revealed by geodetic measurement and small repeating earthquakes show that slow-slip transients occurred in the down-dip and up-dip portions of the mainshock rupture area. These slow-slip transients imply the reduction of coupling between the subducting and overlying plates, that could be interpreted as the late stage of mega-thrust earthquake cycle, although this notion remains conjectural.

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Minson, Sarah E., Benjamin A. Brooks, Craig L. Glennie, Jessica R. Murray, John O. Langbein, Susan E. Owen, Thomas H. Heaton, Robert A. Iannucci, and Darren L. Hauser. "Crowdsourced earthquake early warning." Science Advances 1, no. 3 (April 2015): e1500036. http://dx.doi.org/10.1126/sciadv.1500036.

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Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes and tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions of the sensors used in EEW. Although less accurate than scientific-grade instruments, these sensors are globally ubiquitous. Through controlled tests of consumer devices, simulation of anMw(moment magnitude) 7 earthquake on California’s Hayward fault, and real data from theMw9 Tohoku-oki earthquake, we demonstrate that EEW could be achieved via crowdsourcing.

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Kiser, Eric, and Haiyang Kehoe. "The hazard of coseismic gaps: the 2021 Fukushima earthquake." Geophysical Journal International 227, no. 1 (May 27, 2021): 54–57. http://dx.doi.org/10.1093/gji/ggab208.

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SUMMARY Subduction zones are associated with significant seismic hazards around the world and determining the future locations of large earthquakes within these systems is a perpetual challenge of the Earth sciences. This study presents back-projection results from the 2021 Mw 7.1 Fukushima earthquake which show that the rupture area of this event filled a previously identified coseismic gap within the rupture area of the 2011 Mw 9.1 Tohoku-oki earthquake. These results, combined with observations of a similar coseismic gap from the 2010 Mw 8.8 Maule, Chile earthquake that was subsequently filled by a Mw 7.1 aftershock, demonstrate that future assessments of seismic hazards following giant earthquakes should include the identification of coseismic gaps left within main shock rupture areas.

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Matsumoto, Satoshi, Tomomi Okada, Toshiko Terakawa, Makoto Uyeshima, and Yoshihisa Iio. "The Advancement of Research on Inland Earthquake Generation 2014–2018." Journal of Disaster Research 15, no. 2 (March 20, 2020): 96–105. http://dx.doi.org/10.20965/jdr.2020.p0096.

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The 2011 Tohoku-Oki Earthquake (M9.0) significantly affected inland areas of Japan. The crust and mantle response to the magathrust earthquake induced changes in the mechanical conditions of the seismogenic zone. Here we present important progress in the research into the seismogenesis of inland earthquakes. Stress, strain, strength, and structures are key parameters affecting the occurrence of earthquakes. In particular, both the spatial and temporal changes in these parameters around the focal areas of the large inland earthquakes have been detected and modeled. These results have provided spatial potential evaluation in terms of future inland earthquake occurrence. However, we clearly recognize that, in order to understand and predict the inland earthquake generation process, it will inevitably be necessary to unify the research on various spatial and temporal scales, from problems related to long-term stress loading from plate-relative motion to instant fault response.

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Nishimura, Takuya. "Pre-, Co-, and Post-Seismic Deformation of the 2011 Tohoku-Oki Earthquake and its Implication to a Paradox in Short-Term and Long-Term Deformation." Journal of Disaster Research 9, no. 3 (June 1, 2014): 294–302. http://dx.doi.org/10.20965/jdr.2014.p0294.

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The 2011 Tohoku-oki earthquake caused large eastward displacement and subsidence along the Pacific coast of northeastern Japan. This earthquake partly solved a well-known paradox holding that sense and rate of deformation differ greatly between geologic and geodetic estimates. A paradox remains, however, in explaining long-term uplift along the Pacific coast on a geologic time-scale. Geodetic data show that coastal subsidence continued at a nearly constant rate of ∼5 mm/yr with small fluctuations associated with M7-8 interplate earthquakes for ∼120 years before the Tohoku-oki earthquake. In an area near the Oshika Peninsula where coseismic subsidence is largest, extrapolation of a logarithmic function fitting observed postseismic deformation suggests that coseismic subsidence may be compensated for by the postseismic uplift for several decades but it is difficult to expect the postseismic uplift exceeding 2 meters, so it is implausible that the observed rapid subsidence continued throughout an entire interseismic period in a great megathrust earthquake cycle. We propose a hypothetical model in which the sense of vertical deformation changes from uplift to subsidence during the interseismic period. Using simple elastic dislocation theory, this model is explained by the shallow coupled part of a plate interface in an early interseismic period and the deep coupled part of a late interseismic period.

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Huang, Zhouchuan, and Dapeng Zhao. "Relocating the 2011 Tohoku-oki earthquakes (M 6.0–9.0)." Tectonophysics 586 (February 2013): 35–45. http://dx.doi.org/10.1016/j.tecto.2012.10.019.

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Tanaka, Sachiko. "Tidal triggering of earthquakes prior to the 2011 Tohoku-Oki earthquake (Mw9.1)." Geophysical Research Letters 39, no. 7 (April 2012): n/a. http://dx.doi.org/10.1029/2012gl051179.

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Takada, Youichiro, and Yo Fukushima. "Volcanic Subsidence Triggered by Megathrust Earthquakes." Journal of Disaster Research 9, no. 3 (June 1, 2014): 373–80. http://dx.doi.org/10.20965/jdr.2014.p0373.

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Studies using spaceborne interferometric synthetic aperture radar (InSAR) analysis showed that two megathrust earthquakes – the 2011Mw9.0 Tohoku-oki earthquake in Japan and the 2010Mw8.8Maule earthquake in Chile – triggered unprecedented subsidence in multiple volcanoes. There are strong similarities in the characteristics of the surface deformation in Japan and Chile: (1) Maximum subsidence is about 15 cm. (2) Areas of subsidence are elliptically elongated in a north-south direction perpendicular to the principal axis of the extensional stress change. (3) Most of this subsidence is coseismic. These similarities imply that volcanic subsidence triggered by the megathrust earthquakes is a ubiquitous phenomenon. Nonetheless, the mechanism of subsidence is yet to be investigated. Two main hypotheses have been proposed thus far: 1) The localized deformation of hot and weak plutonic bodies. 2) Water release from large hydrothermal reservoirs beneath the volcanoes.

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Hirata, Naoshi, and Aitaro Kato. "Special Issue on Challenges of Earthquake Forecast Research Illuminated by the 2011 Tohoku-Oki Earthquake." Journal of Disaster Research 9, no. 3 (June 1, 2014): 247. http://dx.doi.org/10.20965/jdr.2014.p0247.

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The 2011 off the Pacific coast of Tohoku Earthquake, hereafter referred to as Tohoku-Oki earthquake, occurring off northeastern Japan’s Pacific coast on March 11, 2011 had a moment magnitude of 9.0 and generated a tsunami responsible for most of the deaths of the event’s 19,000 victims. Identifying scientifically what happened before, on, and after March 11 is one starting point for a discussion on how to reduce casualties and mitigate the impact of such natural disasters. The 14 papers in this special issue cover incidents related to pre-, co- and post-seismic phenomena, including volcanoes. Three papers discuss why and how such a large quake occurred. Three more papers go into the implications of short- and long-term crustal deformations seen in northeastern Japan. Four papers detail short- and long-term phenomena leading to the Tohoku-Oki quake. Two papers discuss real-time tsunami forecasting based on off-shore and on-shore geodetic, seismic and tsunami observation data. The last two papers explore the effects of the 2011 temblor on volcanic phenomena. The magnitude 9.0 produced in the 2011 event is the largest historically recorded in Japan and may not necessarily have been anticipated beforehand, and the generation mechanism behind such a gigantic occurrence is not yet completely understood. Even so, preparations should be made for such earthquakes in other parts of Japan and in other countries. The Nankai trough is an example of areas that require our attention. A national project for observation and study for earthquake prediction is now being integrated into a new program, Earthquake and Volcano Hazards Observation and Research Program (2014-2019). Studies presented in this special issue are also being supported in part by this program. We are certain that readers will find that this special issue will contribute much to our understanding of gigantic earthquakes and at least some of the measure to be taken in preparation for such natural phenomena. Finally, we extend our sincere thanks to all of the contributors and reviewers involved with these articles.

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Ide, Satoshi, and Hideo Aochi. "Modeling Earthquakes Using Fractal Circular Patch Models with Lessons from the 2011 Tohoku-Oki Earthquake." Journal of Disaster Research 9, no. 3 (June 1, 2014): 264–71. http://dx.doi.org/10.20965/jdr.2014.p0264.

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Earthquakes occur in a complex hierarchical fault system, meaning that a realistic mechanically-consistent model is required to describe heterogeneity simply and over a wide scale. We developed a simple conceptual mechanical model using fractal circular patches associated with fracture energy on a fault plane. This model explains the complexity and scaling relation in the dynamic rupture process. We also show that such a fractal patch model is useful in simulating longterm seismicity in a hierarchal fault system by using external loading. In these studies, an earthquake of any magnitude appears as a completely random cascade growing from a small patch to larger patches. This model is thus potentially useful as a benchmarking scenario for evaluating probabilistic gain in probabilistic earthquake forecasts. The model is applied to the real case of the 2011 Tohoku-Oki earthquake based on prior information from a seismicity catalog to reproduce the complex rupture process of this very large earthquake and its resulting ground motion. Provided that a high-quality seismicity catalog is available for other regions, similar approach using this conceptual model may provide scenarios for other potential large earthquakes.

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Nishimura, Takuya. "A Trial Application of Geodetic Data for Inland Fault Assessment – Coulomb Stress Changes Estimated from GNSS Surface Displacements." Journal of Disaster Research 13, no. 3 (June 1, 2018): 489–95. http://dx.doi.org/10.20965/jdr.2018.p0489.

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We examine a method to calculate changes in Coulomb failure stress (ΔCFS) from observed GNSS displacements. The method assumes no stress changes on a horizontal plane and a linear elastic relation between strain and stress, represented by Hooke’s law. The ΔCFS distributions calculated using this method are applied to the 2003 Tokachi-oki and the 2016 Kumamoto earthquakes and they are compared with those using a standard dislocation model buried in an elastic half-space. The results suggest that the ΔCFS distribution at a depth of 10 km in a region far from a deformation source can give a first-order approximation using observations of surface displacements. However, ΔCFS distributions near the source cannot be reproduced by the examined method and need to be evaluated using the standard method. We apply the examined method and GNSS displacement data to calculate ΔCFS on major active faults as well as source faults of large inland earthquakes in southwest Japan for the period 1996-2017. ΔCFS from five large earthquakes, including the 2016 Kumamoto earthquake are separately calculated using the standard method with published fault models. Calculated ΔCFS increases by an order of 10 KPa at most faults over the past 21 years. ΔCFS on the source faults for the 2000 Western Tottori, the 2016 Kumamoto, and the 2016 Central Tottori earthquakes reached a maximum just before their rupture. Coseismic and postseismic deformation of the 2011 Tohoku-oki earthquake accelerated an increase of ΔCFS at some faults, including the source fault of the 2016 Central Tottori earthquake and the Arima-Takatsuki fault zone. The examined method can provide information on the activity of inland earthquakes using contemporarily observed deformation, and can hopefully improve the preparedness for earthquakes.

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Tang, Lu, Jin Li, Jianli Chen, Song-Yun Wang, Rui Wang, and Xiaogong Hu. "Seismic Impact of Large Earthquakes on Estimating Global Mean Ocean Mass Change from GRACE." Remote Sensing 12, no. 6 (March 13, 2020): 935. http://dx.doi.org/10.3390/rs12060935.

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We analyze the impact of large earthquakes on the estimation of the global mean ocean mass (GMOM) change rate over the 13-year period (January 2003 to December 2015) using the Gravity Recovery and Climate Experiment (GRACE) Release-06 (RL06) monthly gravity solutions released by the Center for Space Research (CSR). We take into account the effects of the December 2004 Mw9.1 and April 2012 Mw8.6 Sumatra earthquakes, the March 2011 Mw9.0 Tohoku-Oki earthquake, and the February 2010 Mw8.8 Chile earthquake. After removing the co- and post-seismic effects of these earthquakes in the oceanic areas by least squares fitting, we estimate the GMOM rate from GRACE monthly observations. Results show that GRACE-observed GMOM rate before the seismic correction is 2.12 ± 0.30 mm/year, while after correction the rate is 2.05 ± 0.30 mm/year. Even though the −0.07 ± 0.02 mm/year seismic influence on GRACE GMOM rate is small on a global scale, it is a systematic bias and should be considered for improved quantification and understanding of the global sea level change.

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Koyama, Junji, Kazunori Yoshizawa, Kiyoshi Yomogida, and Motohiro Tsuzuki. "Variability of megathrust earthquakes in the world revealed by the 2011 Tohoku-oki Earthquake." Earth, Planets and Space 64, no. 12 (December 2012): 1189–98. http://dx.doi.org/10.5047/eps.2012.04.011.

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Goda, Katsuichiro, and Gail M. Atkinson. "Variation of Source-to-Site Distance for Megathrust Subduction Earthquakes: Effects on Ground Motion Prediction Equations." Earthquake Spectra 30, no. 2 (May 2014): 845–66. http://dx.doi.org/10.1193/080512eqs254m.

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This study investigates the effects of using different finite-fault source models in evaluating rupture distances for megathrust subduction earthquakes. The uncertainty of the calculated rupture distances affects interpretation of the recorded ground motions significantly. To demonstrate this from an empirical perspective, ground motion data and available finite-fault models for the 2011 M9.0 Tohoku, 2003 M8.3 Tokachi-oki, and 2005 M7.2 Miyagi-oki earthquakes are analyzed. The impact of different finite-fault models on the development of ground motion prediction equations for these large subduction events is significant. Importantly, the results suggest that comparison of observed ground motion data with existing ground motion prediction models is not straightforward; different conclusions may be reached regarding agreement/disagreement between empirical data and developed models, depending on the selected finite-fault model. These results are particularly relevant to the development of ground motion prediction equations for subduction regions.

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Kodaira, Shuichi, Takeshi Iinuma, and Kentaro Imai. "Investigating a tsunamigenic megathrust earthquake in the Japan Trench." Science 371, no. 6534 (March 11, 2021): eabe1169. http://dx.doi.org/10.1126/science.abe1169.

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The 2011 Tohoku-oki earthquake occurred in the Japan Trench 10 years ago, where devastating earthquakes and tsunamis have repeatedly resulted from subduction of the Pacific plate. Densely instrumented seismic, geodetic, and tsunami observation networks precisely recorded the event, including seafloor observations. A large coseismic fault slip that unexpectedly extended to a shallow part of megathrust fault was documented. Strong lateral variations of the coseismic slip near the trench were recorded from marine geophysical studies, along with a possible cause of these variations. The seismic activities in east Japan are still higher than those before the earthquake, and crustal deformation is still occurring. Although the recurrence probability of a great earthquake (magnitude = ~9) in the Japan Trench in the near future is very low, a large normal fault earthquake seaward of the Japan Trench is a concerning possibility.

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Won, Byeongho, Se-Yeong Hamm, Kue-Young Kim, Kyoochul Ha, Jehyun Shin, Seho Hwang, and Soo-Hyoung Lee. "Response Analysis of Multi-Layered Volcanic Aquifers in Jeju Island to the 2011 M9.0 Tohoku-Oki Earthquake." Water 11, no. 5 (May 5, 2019): 942. http://dx.doi.org/10.3390/w11050942.

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Seismic waves caused by earthquakes can lead to the movement of fresh groundwater and saltwater in coastal aquifers. The groundwater level, temperature, and electrical conductivity in coastal monitoring wells on the volcanic island of Jeju all responded to the 2011 M 9.0 Tohoku-Oki earthquake. As a result of the earthquake, groundwater temperature and electrical conductivity patterns demonstrated freshwater outflow and saltwater inflow through the monitoring wells in multi-layered coastal aquifers. The seismicity also affected the behavior of ocean tides occurring at depth along the multi-layered coastal aquifers. These observations prove that the use of multi-depth systems for monitoring groundwater level, temperature, and electrical conductivity are more effective than single monitoring systems for understanding the exact behavior of multi-layered aquifers as well as efficiently detecting earthquake-induced or anthropogenic impacts on aquifers in coastal, karstic, or volcanic areas.

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Yoshida, Nozomu, and Kazue Wakamatsu. "Performance of Countermeasures Against Massive Slope Failures in Sendai City During the 2011 Tohoku Earthquake." Journal of Disaster Research 11, sp (September 1, 2016): 798–810. http://dx.doi.org/10.20965/jdr.2016.p0798.

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This paper presents a case history of extensive damage due to large-scale slope failure during two successive earthquakes and the positive impact of countermeasures in Midorigaoka, Sendai, Japan. We detail damage during the two earthquakes, postquake countermeasures, and problems encountered during restoration. The area was damaged during the 1978 Miyagiken-oki Earthquake, after which countermeasures were deployed. The most significant damage was at Midorigaoka 1-chome, where 18 houses were demolished and two areas were abandoned. Extensive countermeasures such as a collecting well, landslide prevention piles, and retaining walls were implemented here. In Midorigaoka 3-chome, 14 houses were demolished and two areas were abandoned. Landslide prevention piles were installed and a landslide-controlling dam constructed. Failure was only superficial at Midorigaoka 4-chome, so no heavy remedial work was needed. The Midorigaoka district was hit again by the 2011 Tohoku Earthquake, although no damage was observed at 1-chome. Damage at 3-chome resembled that in the 1978 earthquake. Ground movement of up to 1–2 m was induced at Midorigaoka 4-chome, where approximately 100 houses collapsed and the area itself was forbidden for housing use. The degree of damage during this earthquake depended upon countermeasures adopted after the 1978 earthquake.

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OKUDA, Takashi, Naoki UCHIDA, and Youichi ASANO. "Detection of Small Earthquakes Using the Matched Filter Method Immediately After the Tohoku-Oki Earthquake." Zisin (Journal of the Seismological Society of Japan. 2nd ser.) 71 (July 10, 2018): 87–101. http://dx.doi.org/10.4294/zisin.2017-8.

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OKUDA, Takashi, Naoki UCHIDA, and Youichi ASANO. "Detection of Small Earthquakes Using the Matched Filter Method Immediately After the Tohoku-Oki Earthquake." Zisin (Journal of the Seismological Society of Japan. 2nd ser.) 71 (July 10, 2018): 87–101. http://dx.doi.org/10.4294/zisin.71.2017-8.

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Feng, Guangcai, and Sigurjón Jónsson. "Shortcomings of InSAR for studying megathrust earthquakes: The case of the Mw9.0 Tohoku-Oki earthquake." Geophysical Research Letters 39, no. 10 (May 22, 2012): n/a. http://dx.doi.org/10.1029/2012gl051628.

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Delbridge, Brent G., Saeko Kita, Naoki Uchida, Christopher W. Johnson, Toru Matsuzawa, and Roland Bürgmann. "Temporal variation of intermediate-depth earthquakes around the time of the M 9.0 Tohoku-oki earthquake." Geophysical Research Letters 44, no. 8 (April 24, 2017): 3580–90. http://dx.doi.org/10.1002/2017gl072876.

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Kim, Byungmin, and Youssef M. A. Hashash. "Site Response Analysis Using Downhole Array Recordings during the March 2011 Tohoku-Oki Earthquake and the Effect of Long-Duration Ground Motions." Earthquake Spectra 29, no. 1_suppl (March 2013): 37–54. http://dx.doi.org/10.1193/1.4000114.

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Downhole arrays provide enhanced understanding of dynamic soil behavior and site response. Historically, downhole array recordings have been available only for earthquakes with relatively limited durations. New recordings from a number of KiK-net downhole arrays during the 11 March 2011, Mw 9.0, subduction zone earthquake near the east coast of Honshu, Japan, allow us to investigate dynamic soil characteristics and site response due to long-duration subduction zone earthquakes. Using these recordings, we perform one-dimensional site response analyses to evaluate the applicability of commonly used analysis approaches under long-duration earthquakes. We find that site response analyses capture key features of measured surface response spectra particularly at soft rock/stiff soil sites subject to long-duration motion. However, at softer soil sites, it appears that the modulus reduction is overestimated and site-specific characterization is needed.

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Obana, Koichiro, Gou Fujie, Yojiro Yamamoto, Yuka Kaiho, Yasuyuki Nakamura, Seiichi Miura, and Shuichi Kodaira. "Seismicity around the trench axis and outer-rise region of the southern Japan Trench, south of the main rupture area of the 2011 Tohoku-oki earthquake." Geophysical Journal International 226, no. 1 (March 9, 2021): 131–45. http://dx.doi.org/10.1093/gji/ggab093.

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SUMMARY The 2011 Mw 9.0 Tohoku-oki earthquake ruptured the subduction megathrust fault in the central Japan Trench. We investigated the aftershock activity in the southern Japan Trench to the south of the main rupture area using ocean bottom seismographs deployed both landward and seaward of the trench. In the trench-outer rise region seaward of the trench axis, we identified several ∼100-km-long linear earthquake trends both parallel and oblique to the southern Japan Trench. The earthquake trend oblique to the southern Japan Trench is a southward extension of the trench-parallel linear earthquake trend in the central to northern Japan Trench. The trench-parallel normal-faults in the trench-outer rise region could extend linearly, despite the change of the trench strike from N–S to NNE–SSW to the south of the main rupture area. Normal-faults oblique to the trench should be considered as substantial parts of large intraplate normal-faulting earthquakes. In addition, intraplate seismicity coinciding with the lower velocity oceanic mantle suggest that the structure heterogeneity would be indicative of normal-faults extending into the mantle. In the trench landward area, earthquake activity showed along-trench variations. Earthquakes along the shallow megathrust interface near the trench were observed south of 37°N. These shallow near-trench regular earthquakes, which are located close to the episodic tremors and temporally correlated with the tremor activities, suggest that the afterslip on the plate interface likely extended to the shallow plate interface close to the trench axis. Smaller spatial scale structure heterogeneity, such as the thickness variation in the channel-like low-velocity sedimentary unit, likely relate to the proximity of the regular earthquakes and slow slip which results in the formation of diverse slip behaviours in the shallow subduction zone of the southern Japan Trench.

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Dhar, Sambuddha, Jun Muto, Yoshiaki Ito, Satoshi Miura, James D. P. Moore, Yusaku Ohta, and Takeshi Iinuma. "Along-arc heterogeneous rheology inferred from post-seismic deformation of the 2011 Tohoku-oki earthquake." Geophysical Journal International 230, no. 1 (February 15, 2022): 202–15. http://dx.doi.org/10.1093/gji/ggac063.

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SUMMARY The Japan forearc plays a crucial role in modulating the post-seismic deformation in response to the enormous stress perturbation induced by the 2011 Tohoku-oki earthquake. Dense geodetic observations across Japan have revealed coupled interactions between afterslip on the subducting plate interface and viscous deformation within the mantle wedge, and detailed numerical models can provide further profound insights into the forearc rheology. Recent studies have revealed the presence of a stagnant section in the forearc mantle of the Tohoku subduction zone, and here we investigate the associated along-arc variation of the stagnant part of the mantle wedge (cold nose) across Japan. We utilize a newly deployed geodetic network along a corridor in the Fukushima–Niigata region and compare the surface deformation pattern to that of the Miyagi–Yamagata corridor close to the main rupture area. We present a 3-D rheological model using laboratory-derived constitutive laws to simulate the geodetic observations including displacement fields and their time-series. Our results suggest along-arc heterogeneity in the forearc mantle rheology; specifically, we find a narrower cold nose in the Miyagi region and a wider one in the Fukushima forearc. The geodetic inferences on the forearc variation are consistent with along-arc spatial heterogeneity in the cut-off depth for shallow earthquakes as well as comparative measurements of the respective geothermal gradients between the Miyagi and Fukushima regions.

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To, Akiko, Koichiro Obana, Hiroko Sugioka, Eiichiro Araki, Narumi Takahashi, and Yoshio Fukao. "Small size very low frequency earthquakes in the Nankai accretionary prism, following the 2011 Tohoku-Oki earthquake." Physics of the Earth and Planetary Interiors 245 (August 2015): 40–51. http://dx.doi.org/10.1016/j.pepi.2015.04.007.

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Peng, Zhigang, Hector Gonzalez‐Huizar, Kevin Chao, Chastity Aiken, Bladimir Moreno, and Gregory Armstrong. "Tectonic Tremor beneath Cuba Triggered by theMw 8.8 Maule andMw 9.0 Tohoku‐Oki Earthquakes." Bulletin of the Seismological Society of America 103, no. 1 (February 2013): 595–600. http://dx.doi.org/10.1785/0120120253.

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Stewart, Jonathan P., Saburoh Midorikawa, Robert W. Graves, Khatareh Khodaverdi, Tadahiro Kishida, Hiroyuki Miura, Yousef Bozorgnia, and Kenneth W. Campbell. "Implications of the Mw9.0 Tohoku-Oki Earthquake for Ground Motion Scaling with Source, Path, and Site Parameters." Earthquake Spectra 29, no. 1_suppl (March 2013): 1–21. http://dx.doi.org/10.1193/1.4000115.

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The Mw9.0 Tohoku-oki Japan earthquake produced approximately 2,000 ground motion recordings. We consider 1,238 three-component accelerograms corrected with component-specific low-cut filters. The recordings have rupture distances between 44 km and 1,000 km, time-averaged shear wave velocities of VS30 = 90 m/s to 1,900 m/s, and usable response spectral periods of 0.01 sec to >10 sec. The data support the notion that the increase of ground motions with magnitude saturates at large magnitudes. High-frequency ground motions demonstrate faster attenuation with distance in backarc than in forearc regions, which is only captured by one of the four considered ground motion prediction equations for subduction earthquakes. Recordings within 100 km of the fault are used to estimate event terms, which are generally positive (indicating model underprediction) at short periods and zero or negative (overprediction) at long periods. We find site amplification to scale minimally with VS30 at high frequencies, in contrast with other active tectonic regions, but to scale strongly with VS30 at low frequencies.

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Mavrommatis, Andreas P., Paul Segall, Naoki Uchida, and Kaj M. Johnson. "Long-term acceleration of aseismic slip preceding the M w 9 Tohoku-oki earthquake: Constraints from repeating earthquakes." Geophysical Research Letters 42, no. 22 (November 19, 2015): 9717–25. http://dx.doi.org/10.1002/2015gl066069.

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Ando, M., M. Ishida, Y. Hayashi, C. Mizuki, Y. Nishikawa, and Y. Tu. "Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake." Natural Hazards and Earth System Sciences 13, no. 9 (September 6, 2013): 2173–87. http://dx.doi.org/10.5194/nhess-13-2173-2013.

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Abstract. One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake) (Mw = 9.0) were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

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Cibeira Urtiaga, Ángel, Manuel Berrocoso, Belén Rosado, and Antonio Pazos. "Detection and study of a high magnitude seismic event from GPS data: Case study of the 2011 Tohoku-Oki earthquake." Earth Sciences Research Journal 26, no. 2 (September 8, 2022): 91–106. http://dx.doi.org/10.15446/esrj.v26n2.97735.

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The advent of GPS provided a new way of measuring surface displacements due to earthquakes by deploying GPS networks within active seismic areas. Japan is located in the confluence of several tectonic plates, hence its seismicity. In order to surveille this activity, one of wider GPS network in the world was deployed, i.e., GEONET. By processing data from 93 GEONET reference stations, we analyze the 2011 Tohoku-Oki earthquake using PPP strategy. We studied the time series during the event setting up a threshold value at we consider the time series are being altered by the earthquake. We also identified the time after the occurrence when the maximum displacements happen. With the study of these two parameters, we aim to show their different behavior as the main shock propagates along the Japan islands, with a focus on a better understanding of the earthquake and its propagation. To achieving this, a least square adjustment method was used to relate epicentral distance to topocentric displacements and the time of detection to epicentral distance. The results show an exponential behavior of the distance-displacement regression versus a linear behavior of the distance-time regression. Besides, we use the former linear regression to calculate and approximation of the velocity of the shock waves.

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Grant, Fred F., Yuchuan Tang, Greg S. Hardy, and Robert Kassawara. "Seismic Damage Indicating Parameters at Nuclear Power Plants Affected by the 2011 Tohoku-Oki Earthquake and Plant Shutdown Criteria." Earthquake Spectra 33, no. 1 (February 2017): 109–21. http://dx.doi.org/10.1193/042716eqs071m.

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A rational and quantitative shutdown criterion is required for a nuclear power plant in response to seismic shaking to determine whether the plant must be shut down for inspection. The shutdown criterion is generally defined in terms of seismic damage indicating parameters. This paper presents seismic damage indicating parameters of the recorded free-field and in-structure motions at the Onagawa, Fukushima Daiichi, Fukushima Daini, and Tokai Daini nuclear power plants during the 2011 Tohoku-oki earthquake. The observed seismic damage indicating parameters largely exceed the current U.S. and Japan shutdown thresholds for nuclear power plants, while minimal damage due to ground shaking was observed at the four Japanese plants. These observations indicate a potential for raising the current threshold without introducing any significant additional seismic risk to nuclear power plants. The insights presented in this paper can be used to guide regulation and industry methods for quickly evaluating the damage potential of future earthquakes that affect nuclear power plants. With some adjustment, a similar methodology and criterion could be applied to conventional structures and lifeline infrastructure.

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Zhan, Zhongwen, Don Helmberger, Mark Simons, Hiroo Kanamori, Wenbo Wu, Nadaya Cubas, Zacharie Duputel, et al. "Anomalously steep dips of earthquakes in the 2011 Tohoku-Oki source region and possible explanations." Earth and Planetary Science Letters 353-354 (November 2012): 121–33. http://dx.doi.org/10.1016/j.epsl.2012.07.038.

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44

Guilhem, A., D. S. Dreger, H. Tsuruoka, and H. Kawakatsu. "Moment tensors for rapid characterization of megathrust earthquakes: the example of the 2011 M 9 Tohoku-oki, Japan earthquake." Geophysical Journal International 192, no. 2 (November 26, 2012): 759–72. http://dx.doi.org/10.1093/gji/ggs045.

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45

Yoshida, Keisuke, Akira Hasegawa, Tomomi Okada, Takeshi Iinuma, Yoshihiro Ito, and Youichi Asano. "Stress before and after the 2011 great Tohoku-oki earthquake and induced earthquakes in inland areas of eastern Japan." Geophysical Research Letters 39, no. 3 (February 2012): n/a. http://dx.doi.org/10.1029/2011gl049729.

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Uchide, Takahiko, Peter M. Shearer, and Kazutoshi Imanishi. "Stress drop variations among small earthquakes before the 2011 Tohoku-oki, Japan, earthquake and implications for the main shock." Journal of Geophysical Research: Solid Earth 119, no. 9 (September 2014): 7164–74. http://dx.doi.org/10.1002/2014jb010943.

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Uchida, Naoki, Kouhei Shimamura, Toru Matsuzawa, and Tomomi Okada. "Postseismic response of repeating earthquakes around the 2011 Tohoku-oki earthquake: Moment increases due to the fast loading rate." Journal of Geophysical Research: Solid Earth 120, no. 1 (January 2015): 259–74. http://dx.doi.org/10.1002/2013jb010933.

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Kame, Nobuki. "Pre-P gravity signals from dynamic earthquake rupture: modelling and observations." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2196 (March 15, 2021): 20200136. http://dx.doi.org/10.1098/rsta.2020.0136.

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Dynamic earthquake rupture is one of the most extensive and devastating fracture phenomena on the Earth. It causes a sudden crustal deformation around a fault and generates seismic waves that induce bulk density variations propagating with them. Both processes constitute rock-mass redistribution, which is expected to induce simultaneous transient gravity perturbations at all distances before the arrival of P-waves. Interest in such pre-P gravity signals has increased both in terms of modelling and observations because of their potential for earthquake early warning. A simple forward model has pioneered the search for the so-called prompt elasto-gravity signals, which led to the first report of a signal from the 2011 M w 9.0 Tohoku-Oki earthquake using a single superconducting gravimeter record. The second report followed using hundreds of broadband seismometers with critical modification of the previous model to consider the pre-P ground acceleration in the measurement of gravity. Post-event analyses have identified prompt elasto-gravity signals from several large earthquakes, and state-of-the-art instruments are now being developed for real-time signal detection. This paper reviews recent progress in the cutting-edge subject of prompt elasto-gravity signals owing to large-scale earthquake rupture. This article is part of the theme issue ‘Fracture dynamics of solid materials: from particles to the globe’.

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Wright, Tim J., Nicolas Houlié, Mark Hildyard, and Tetsuya Iwabuchi. "Real-time, reliable magnitudes for large earthquakes from 1 Hz GPS precise point positioning: The 2011 Tohoku-Oki (Japan) earthquake." Geophysical Research Letters 39, no. 12 (June 20, 2012): n/a. http://dx.doi.org/10.1029/2012gl051894.

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Kamaya, Noriko, Mitsuyuki Hoshiba, Akio Katsumata, and Keiji Doi. "Continuity of Earthquake and Tsunami Monitoring by Japan Meteorological Agency under Critical Conditions." Seismological Research Letters 92, no. 1 (November 11, 2020): 17–25. http://dx.doi.org/10.1785/0220200259.

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Abstract The Japan Meteorological Agency (JMA) is a governmental organization that has responsibilities for mitigation of natural disasters. JMA issues warnings and information about natural disasters, in addition to daily weather forecasts. When an earthquake occurs, JMA analyzes seismic data to issue an earthquake early warning and to warn of possible tsunamis when a tsunami is expected to strike coastal areas of Japan. During tsunami warning in effect, JMA monitors tsunami meters and updates the warning. JMA also provides several types of macroseismic information. To fulfill these responsibilities, JMA collects data from 4400 seismic intensity meters, 1800 seismometers, 400 tsunami meters, and 39 strainmeters. Monitoring must be continued even under difficult situations such as times following great earthquakes, volcanic eruptions, severe weather conditions, and pandemics. JMA has dual operations centers located in Tokyo and Osaka. When one loses functionality due to a disaster or infection, the other continues 24/7 operations including warnings and issuing other information. Disastrous situations often cause power and communication failures and insufficient numbers of technical specialists. Following the 2011 Tohoku-oki earthquake, JMA enhanced power and communication capabilities by adding large capacity batteries at each station and satellite communication links. During the coronavirus disease 2019 (COVID-19) pandemic, JMA has taken several measures to prevent technical specialists’ infection to continue the full range of functions for issuing of warnings and conveying needed information.

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Journal articles on the topic 'Tohoku-Oki earthquakes'

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