scholarly journals Consecutive Ruptures on a Complex Conjugate Fault System During the 2018 Gulf of Alaska Earthquake

2021 ◽  
Author(s):  
Shinji Yamashita ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Kousuke Shimizu ◽  
Ryoichiro Agata ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Fault System ◽  
Complex Conjugate ◽  
Conjugate Fault ◽  
Alaska Earthquake

scholarly journals Consecutive Ruptures on a Complex Conjugate Fault System During the 2018 Gulf of Alaska Earthquake

2021 ◽  
Author(s):  
Shinji Yamashita ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Kousuke Shimizu ◽  
Ryoichiro Agata ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Fault System ◽  
Complex Conjugate ◽  
Conjugate Fault ◽  
Alaska Earthquake

scholarly journals Consecutive Ruptures on a Complex Conjugate Fault System During the 2018 Gulf of Alaska Earthquake

2021 ◽  
Author(s):  
Shinji Yamashita ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Kousuke Shimizu ◽  
Ryoichiro Agata ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Fault System ◽  
Complex Conjugate ◽  
Conjugate Fault ◽  
Alaska Earthquake

scholarly journals Consecutive ruptures on a complex conjugate fault system during the 2018 Gulf of Alaska earthquake

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinji Yamashita ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Kousuke Shimizu ◽  
Ryoichiro Agata ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Source Model ◽  
Fault System ◽  
Complex Conjugate ◽  
Inversion Method ◽  
Fault Geometry ◽  
Conjugate System ◽  
Finite Fault Inversion ◽  
Finite Fault ◽  
Alaska Earthquake

AbstractWe developed a flexible finite-fault inversion method for teleseismic P waveforms to obtain a detailed rupture process of a complex multiple-fault earthquake. We estimate the distribution of potency-rate density tensors on an assumed model plane to clarify rupture evolution processes, including variations of fault geometry. We applied our method to the 23 January 2018 Gulf of Alaska earthquake by representing slip on a projected horizontal model plane at a depth of 33.6 km to fit the distribution of aftershocks occurring within one week of the mainshock. The obtained source model, which successfully explained the complex teleseismic P waveforms, shows that the 2018 earthquake ruptured a conjugate system of N-S and E-W faults. The spatiotemporal rupture evolution indicates irregular rupture behavior involving a multiple-shock sequence, which is likely associated with discontinuities in the fault geometry that originated from E-W sea-floor fracture zones and N-S plate-bending faults.

Coseismic Slip Model of the 2018 Mw 7.9 Gulf of Alaska Earthquake and Its Seismic Hazard Implications

2018 ◽  
Vol 90 (2A) ◽  
pp. 642-648 ◽  
Author(s):  
Bin Zhao ◽  
Yujie Qi ◽  
Dongzhen Wang ◽  
Jiansheng Yu ◽  
Qi Li ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Gulf Of Alaska ◽  
Slip Model ◽  
Coseismic Slip ◽  
Alaska Earthquake

Moment rate of the 2018 Gulf of Alaska earthquake

2020 ◽  
Vol 298 ◽  
pp. 106336
Author(s):  
Stefano Santini ◽  
Michele Dragoni
Keyword(s):  
Gulf Of Alaska ◽  
Alaska Earthquake

scholarly journals Fault interactions in a complex fault system: insight from the 1936–1997 NE Lut earthquake sequence

2020 ◽  
Vol 224 (2) ◽  
pp. 1157-1173
Author(s):  
M Marchandon ◽  
M Vergnolle ◽  
O Cavalié
Keyword(s):  
Fault System ◽  
Coulomb Stress ◽  
Coulomb Stress Changes ◽  
Fault Systems ◽  
Complex Fault ◽  
Stress Changes ◽  
Fault Interactions ◽  
Seismic Deformation ◽  
Earthquake Sequences ◽  
Conjugate Fault

SUMMARY Calculations of Coulomb stress changes have shown that moderate to large earthquakes may increase stress at the location of future earthquakes. Coulomb stress transfers have thus been widely accepted to explain earthquake sequences, especially for sequences occurring within parallel or collinear fault systems. Relating, under this framework, successive earthquakes occurring within more complex fault systems (i.e. conjugate fault system) is more challenging. In this study, we assess which ingredients of the Coulomb stress change theory are decisive for explaining the succession of three large (Mw 7+) earthquakes that occurred on a conjugate fault system in the NE Lut, East Iran, during a 30-yr period. These earthquakes belong to a larger seismic sequence made up of 11 earthquakes (Mw 5.9+) from 1936 to 1997. To reach our goal, we calculate, at each earthquake date, the stress changes generated by the static deformation of the preceding earthquakes, the following post-seismic deformation due to the viscoelastic relaxation of the lithosphere, and the interseismic deformation since 1936. We first show that accurately modelling the source and receiver fault geometry is crucial to precisely estimating Coulomb stress changes. Then we show that 7 out of 10 earthquakes of the NE Lut sequence, considering the uncertainties, are favoured by the previous earthquakes. Furthermore, the last two M7+ earthquakes of the sequence (1979 and 1997) have mainly been favoured by the moderate Mw ∼ 6 earthquakes. Finally, we investigate the link between the Coulomb stress changes due to previous earthquakes and the rupture extension of the next earthquake and show that a correlation does exist for some earthquakes but is not systematic.

Two Earthquake Sequences Nearly a Century Apart Reveal a Conjugate Seismogenic System in Central Taiwan

2020 ◽  
Vol 91 (3) ◽  
pp. 1469-1481 ◽  
Author(s):  
Ming-Che Hsieh ◽  
Yen-Yu Lin ◽  
Kuo-Fong Ma ◽  
Li Zhao ◽  
Yi-Wun Liao
Keyword(s):  
Active Faults ◽  
Fault System ◽  
High Angle ◽  
Mountain Building ◽  
Good Opportunity ◽  
Building Process ◽  
Orogenic Wedge ◽  
Central Taiwan ◽  
Earthquake Sequences ◽  
Conjugate Fault

Abstract Seismically active central Taiwan is considered part of an orogenic wedge with low-angle east-dipping active faults above a detachment surface and an active mountain-building process later. In 2013, two moderate reverse-faulting earthquakes of magnitudes ML 6.2 and 6.5 occurred in Nantou. They brought to mind the historically damaging sequence of four earthquakes in the same area that claimed a total of 71 lives in 1916. The 2013 earthquake sequence provides a good opportunity to study the 1916 sequence. We compared the historical Omori record of the main event in the 1916 sequence, discovered in the Seismogram Archives at the Earthquake Research Institute, University of Tokyo, and the corresponding simulated Omori records of the 2013 events. Our comparison shows significant similarity among the earthquakes, although they are separated by nearly 100 yr. To understand the seismogenic structure associated with these earthquake sequences, we further studied the source rupture properties of earthquakes in this region since 1999 using local broadband records to determine the rupture fault planes. Results show that all events have similar focal mechanisms with one low-angle east-dipping and another high-angle west-dipping nodal planes. Rupture plane determination indicates that whereas events at shallow depths (<20  km) ruptured on the low-angle east-dipping plane, events at greater depths (>20  km) slipped on the high-angle west-dipping plane in a conjugate fault system. The comparison also suggests that the 1916 sequence occurred on the low-angle east-dipping plane of this conjugate fault system in the orogenic wedge as part of a mountain-building process. Given the active mountain-building process in central Taiwan, occurrences of this type of earthquake must be addressed in seismic hazard mitigation efforts.

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