The Nankai Trough Margin, Record 55-8

1986 ◽  
pp. 54-56 ◽  
Author(s):  
T. Kawamura ◽  
Y. Aoki
Keyword(s):  
Nankai Trough

scholarly journals Driving stress and seismotectonic implications of the 2013 Mw5.8 Awaji Island earthquake, southwestern Japan, based on earthquake focal mechanisms before and after the mainshock

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Kazutoshi Imanishi ◽  
Makiko Ohtani ◽  
Takahiko Uchide
Keyword(s):  
Stress Field ◽  
Stress Tensor ◽  
Nankai Trough ◽  
Source Region ◽  
Local Scale ◽  
Southwest Japan ◽  
Stress Tensor Inversion ◽  
Earthquake Fault ◽  
Reverse Faulting ◽  
Before And After

Abstract A driving stress of the Mw5.8 reverse-faulting Awaji Island earthquake (2013), southwest Japan, was investigated using focal mechanism solutions of earthquakes before and after the mainshock. The seismic records from regional high-sensitivity seismic stations were used. Further, the stress tensor inversion method was applied to infer the stress fields in the source region. The results of the stress tensor inversion and the slip tendency analysis revealed that the stress field within the source region deviates from the surrounding area, in which the stress field locally contains a reverse-faulting component with ENE–WSW compression. This local fluctuation in the stress field is key to producing reverse-faulting earthquakes. The existing knowledge on regional-scale stress (tens to hundreds of km) cannot predict the occurrence of the Awaji Island earthquake, emphasizing the importance of estimating local-scale (< tens of km) stress information. It is possible that the local-scale stress heterogeneity has been formed by local tectonic movement, i.e., the formation of flexures in combination with recurring deep aseismic slips. The coseismic Coulomb stress change, induced by the disastrous 1995 Mw6.9 Kobe earthquake, increased along the fault plane of the Awaji Island earthquake; however, the postseismic stress change was negative. We concluded that the gradual stress build-up, due to the interseismic plate locking along the Nankai trough, overcame the postseismic stress reduction in a few years, pushing the Awaji Island earthquake fault over its failure threshold in 2013. The observation that the earthquake occurred in response to the interseismic plate locking has an important implication in terms of seismotectonics in southwest Japan, facilitating further research on the causal relationship between the inland earthquake activity and the Nankai trough earthquake. Furthermore, this study highlighted that the dataset before the mainshock may not have sufficient information to reflect the stress field in the source region due to the lack of earthquakes in that region. This is because the earthquake fault is generally locked prior to the mainshock. Further research is needed for estimating the stress field in the vicinity of an earthquake fault via seismicity before the mainshock alone.

scholarly journals Broadband Strong-Motion Prediction for Future Nankai-Trough Earthquakes Using Statistical Green’s Function Method and Subsequent Building Damage Evaluation

2021 ◽  
Vol 11 (15) ◽  
pp. 7041
Author(s):  
Baoyintu Baoyintu ◽  
Naren Mandula ◽  
Hiroshi Kawase
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Nankai Trough ◽  
Ground Motions ◽  
Building Damage ◽  
Steel Buildings ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Strong Ground Motions ◽  
Strong Ground

We used the Green’s function summation method together with the randomly perturbed asperity sources to sum up broadband statistical Green’s functions of a moderate-size source and predict strong ground motions due to the expected M8.1 to 8.7 Nankai-Trough earthquakes along the southern coast of western Japan. We successfully simulated seismic intensity distributions similar to the past earthquakes and strong ground motions similar to the empirical attenuation relations of peak ground acceleration and velocity. Using these results, we predicted building damage by non-linear response analyses and find that at the regions close to the source, as well as regions with relatively thick, soft sediments such as the shoreline and alluvium valleys along the rivers, there is a possibility of severe damage regardless of the types of buildings. Moreover, the predicted damage ratios for buildings built before 1981 are much higher than those built after because of the significant code modifications in 1981. We also find that the damage ratio is highest for steel buildings, followed by wooden houses, and then reinforced concrete buildings.

Risk estimation of the disaster waste generated by both ground motion and tsunami due to the anticipated Nankai Trough earthquake

2021 ◽  
Author(s):  
Hiroki Ishibashi ◽  
Mitsuyoshi Akiyama ◽  
Takayuki Kojima ◽  
Koki Aoki ◽  
Shunichi Koshimura ◽  
...  
Keyword(s):  
Ground Motion ◽  
Nankai Trough ◽  
Risk Estimation

scholarly journals Workshop explores seismogenic zone drilling in the Nankai trough

Eos ◽  
2001 ◽  
Vol 82 (45) ◽  
pp. 532-532
Author(s):  
A. Taira ◽  
G. Moore ◽  
H. Tobin ◽  
G. Kimura ◽  
S. Kodaira
Keyword(s):  
Nankai Trough ◽  
Seismogenic Zone

Imaging of the subducted Kyushu-Palau Ridge in the Hyuga-nada region, western Nankai Trough subduction zone

2013 ◽  
Vol 589 ◽  
pp. 90-102 ◽  
Author(s):  
Yojiro Yamamoto ◽  
Koichiro Obana ◽  
Tsutomu Takahashi ◽  
Ayako Nakanishi ◽  
Shuichi Kodaira ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Nankai Trough
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