Reexamination of Tsunami Source Models For the 20th Century Earthquakes Off Hokkaido and Tohoku Along the Eastern Margin of the Sea of Japan

Author(s):  
Satoko Murotani ◽  
Kenji Satake ◽  
Takeo Ishibe ◽  
Tomoya Harada

Abstract Large earthquakes around Japan occur not only in the Pacific Ocean but also in the Sea of Japan, and cause both damage from the earthquake itself and from the ensuing tsunami to the coastal areas. Recently, offshore active fault surveys were conducted in the Sea of Japan by the Integrated Research Project on Seismic and Tsunami Hazards around the Sea of Japan (JSPJ), and their fault models (length, width, strike, dip, and slip angles) have been obtained. We examined the causative faults of M7 or larger earthquakes in the Sea of Japan during the 20th century using seismic and tsunami data. The 1940 off Shakotan Peninsula earthquake (MJMA 7.5) appears to have been caused by the offshore active faults MS01, MS02, ST01, and ST02 as modelled by the JSPJ. The 1993 off the southwest coast of Hokkaido earthquake (MJMA 7.8) likely occurred on the offshore active faults OK03a, OK03b, and OK05, while the 1983 Central Sea of Japan earthquake (MJMA 7.7) probably related to MMS01, MMS04, and MGM01. For these earthquakes, the observed tsunami waveforms were basically reproduced by tsunami numerical simulation from the offshore active faults with the slip amounts obtained by the scaling relation with three stages between seismic moment and source area for inland earthquakes. However, the observed tsunami runup heights along the coast were not reproduced at certain locations, possibly because of the coarse bathymetry data used for the simulation. The 1983 west off Aomori (MJMA 7.1) and the 1964 off Oga Peninsula (MJMA 6.9) earthquakes showed multiple faults near the source area that could be used to reproduce the observed tsunami waveforms; therefore, we could not identify the causative faults. Further analysis using near-field seismic waveforms is required for their identification of their causative faults and their parameters. The scaling relation for inland earthquakes can be used to obtain the slip amounts for offshore active faults in the Sea of Japan and to estimate the coastal tsunami heights and inundation area which can be useful for disaster prevention and mitigation of future earthquakes and tsunamis in the Sea of Japan.

2021 ◽  
Author(s):  
Hafize Başak Bayraktar ◽  
Antonio Scala ◽  
Stefano Lorito ◽  
Manuela Volpe ◽  
Carlos Sánchez Linares ◽  
...  

<p>Tsunami hazard depends strongly on the slip distribution of a causative earthquake. Simplified uniform slip models lead to underestimating the tsunami wave height which would be generated by a more realistic heterogeneous slip distribution, both in the near-field and in the far-field of the tsunami source. Several approaches have been proposed to generate stochastic slip distributions for tsunami hazard calculations, including in some cases shallow slip amplification (Le Veque et al., 2016; Sepulveda et al., 2017; Davies 2019; Scala et al., 2020). However, due to the relative scarcity of tsunami data, the inter-comparison of these models and the calibration of their parameters against observations is a challenging yet very much needed task, also in view of their use for tsunami hazard assessment.</p><p>Davies (2019) compared a variety of approaches, which consider both depth-dependent and depth-independent slip models in subduction zones by comparing the simulated tsunami waveforms with DART records of 18 tsunami events in the Pacific Ocean. Model calibration was also proposed by Davies and Griffin (2020).</p><p>Here, to further progress along similar lines, we compare synthetic tsunamis produced by kinematic slip models obtained with teleseismic inversions from Ye et al. (2016) and by recent stochastic slip generation techniques (Scala et al., 2020) against tsunami observations at open ocean DART buoys, for the same 18 earthquakes and ensuing tsunamis analyzed by Davies (2019). Given the magnitude and location of the real earthquakes, we consider ensembles of consistent slipping areas and slip distributions, accounting for both constant and depth-dependent rigidity models. Tsunami simulations are performed for about 68.000 scenarios in total, using the Tsunami-HySEA code (Macías et al., 2016). The simulated results are validated and compared to the DART observations in the same framework considered by Davies (2019).</p>


2012 ◽  
Vol 132 (6) ◽  
pp. 560-567 ◽  
Author(s):  
Megumu Miki ◽  
Toru Miki ◽  
Akira Asakawa ◽  
Takatoshi Shindo ◽  
Shigeru Yokoyama

2011 ◽  
Vol 131 (12) ◽  
pp. 973-978 ◽  
Author(s):  
Fumiyuki Fujii ◽  
Masaru Ishii ◽  
Mikihisa Saito ◽  
Michihiro Matsui ◽  
Daisuke Natsuno

Author(s):  
G.G. Tkachenko

Морское побережье является одной из самых выраженных естественных географических границ, которая одновременно разделяет и связывает географические структуры суши морей или океанов. В основе формирования типов природопользования в прибрежных зонах, как и на других типах географического пространства, лежит природноресурсный потенциал. Природноресурсный потенциал и типы природопользования как явления пространственнодифференцированные должны быть рассмотрены, прежде всего, в рамках классических географических подходов и оценок, таких как районирование территории и акватории. При этом пространственные сочетания наземных и морских природных, природноресурсных компонентов рассматриваются как важнейшие предпосылки инфраструктурного и хозяйственного развития прибрежных регионов. Необходимым этапом природноресурсного районирования является выявление границ, при пересечении которых существенно меняются природные ресурсы и условия. Данная работа выполнена на примере рассмотрения минеральных ресурсов прибрежных муниципальных образований и является частью исследования природноресурсных сочетаний зоны сушаокеан Дальнего Востока России в рамках изучения пространственной дифференциации факторов, условий и ограничений формирования и развития структур природопользования в прибрежной зоне Тихоокеанской России с учетом воздействия экстремальных природных процессов и явлений. Дана сравнительная характеристика месторождений минерального сырья российской части побережья Японского моря. Определена их видовая и географическая структура. На основе того, что месторождения минерального сырья сгруппированы в 8 основных ресурсных групп ввыполнено районирование российской части побережья Японского моря по сочетанию основных видов минеральных ресурсов. Выделены типы муниципальных образований по сочетанию минеральных ресурсов и показаны особенности каждого из них. Выделены шесть районов по сочетанию минеральных ресурсов. В связи с необходимостью учета географической особенности в сочетании со спецификой минеральных ресурсов, северной и южной частям территории одного типа районов присвоены свои собственные названия. По результатам исследования была построена карта. The seacoast is one of the most pronounced natural geographical boundaries, which divides and connects simultaneously the geographical structures of the land, seas or oceans. The formation of the types of nature management in coastal zones, as well as on other types of geographical space, is based on the natural resource potential. Being spatially differentiated phenomena, the natural resource potential and the types of environmental management should be considered, first of all, within the framework of classical geographical approaches and assessments, such as zoning of the territory and water areas. In this case, spatial combinations of the land and sea natural, naturalresource components are considered as the most important prerequisites for the infrastructure and economic development of coastal regions. Identification of borders, at the intersection of which the natural resources and conditions change significantly, is a necessary stage of natural resource zoning. This work is carried out by example of consideration of mineral resources of coastal municipal unions and appears to be a part of studies of naturalresource combinations of the landocean zone of the Russian Far East in the framework of studies of spatial differentiation of factors, conditions and restrictions of formation and development of structures of nature management in the coastal zone of Pacific Russia, taking into account the influence of extreme natural processes and phenomena. The comparative characteristic of mineral deposits of the Russian part of the coast of the Sea of Japan is given. Their species and a geographical structure are determined. Based on the fact that the mineral deposits are grouped into eight main resource groups, zoning of the Russian part of the coast of the Sea of Japan by a combination of the main types of mineral resources is performed. The types of municipalities are allocated by a combination of mineral resources and their features are shown. Six areas are singled out by a combination of mineral resources. Due to the need to take into account the geographical features in combination with the specifics of mineral resources, the northern and southern parts of the territory of one type of areas have obtained their own names. According to the results of the studies, the map has been compiled.


2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Tatsuo Ohmachi ◽  
Shusaku Inoue ◽  
Tetsuji Imai

The 2003 Tokachi-oki earthquake (MJ 8.0) occurred off the southeastern coast of Tokachi, Japan, and generated a large tsunami which arrived at Tokachi Harbor at 04:56 with a wave height of 4.3 m. Japan Marine Science and Technology Center (JAMSTEC) recovered records of water pressure and sea-bed acceleration at the bottom of the tsunami source region. These records are first introduced with some findings from Fourier analysis and band-pass filter analysis. Water pressure disturbance lasted for over 30 minutes and the duration was longer than those of accelerations. Predominant periods of the pressure looked like those excited by Rayleigh waves. Next, numerical simulation was conducted using the dynamic tsunami simulation technique able to represent generation and propagation of Rayleigh wave and tsunami, with a satisfactory result showing validity and usefulness of this technique. Keywords: Earthquake, Rayleigh wave, tsunami, near-field


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