scholarly journals Co-Seismic Inversion and Post-Seismic Deformation Mechanism Analysis of 2019 California Earthquake

2021 ◽  
Vol 13 (4) ◽  
pp. 608
Author(s):  
Chengsheng Yang ◽  
Ting Wang ◽  
Sainan Zhu ◽  
Bingquan Han ◽  
Jihong Dong ◽  
...  
Keyword(s):  
Seismic Inversion ◽  
Slip Distribution ◽  
Focal Mechanism Solution ◽  
Dislocation Model ◽  
Seismic Events ◽  
Mechanism Analysis ◽  
Seismic Slip ◽  
Tectonic Environment ◽  
Maximum Subsidence ◽  
Seismic Deformation

In July 2019, a series of seismic events, including a magnitude (Mw) 7.1 mainshock and Mw 6.4 foreshock, occurred in Eastern California. Studying these seismic events can significantly improve our understanding of the Eastern California tectonic environment. Sentinel-1A and ALOS-2 PALSAR images were utilized to obtain co-seismic deformation fields, including mainshock and foreshock deformation. The Okada elastic dislocation model and ascending and descending orbit results were used to invert the co-seismic slip distribution and obtain a co-seismic focal mechanism solution. Using ascending Sentinel-1A images, a time-series deformation was obtained for 402 d after the earthquake, and the deformation evolution mechanism was analyzed. The maximum uplift caused by the co-seismic mechanism reached 1.5 m in the line of sight (LOS), and the maximum subsidence reached 1 m in the LOS. For 402 d after the earthquake, the area remained active, and its deformation was dominated by after-slip. The co-seismic inversion results illustrated that California earthquakes were mainly strike-slip. The co-seismic inversion magnitude was approximately Mw 7.08. The Coulomb stress change illustrated that the seismic moment caused by the co-seismic slip was 4.24 × 1026 N × m, which is approximately Mw 7.06. This finding is consistent with the co-seismic slip distribution inversion results.

scholarly journals Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Gao ◽  
HuRong Duan ◽  
YongZhi Zhang ◽  
JiaYing Chen ◽  
HeTing Jian ◽  
...  
Keyword(s):  
Strike Slip ◽  
Fault Slip ◽  
Slip Distribution ◽  
Synthetic Aperture ◽  
Seismic Events ◽  
Interferometric Synthetic Aperture Radar ◽  
The Past ◽  
Dextral Strike Slip Fault ◽  
Fault Slip Distribution ◽  
Dextral Strike Slip

AbstractThe 2019 Ridgecrest, California seismic sequence, including an Mw6.4 foreshock and Mw7.1 mainshock, represent the largest regional seismic events within the past 20 years. To obtain accurate coseismic fault-slip distribution, we used precise positioning data of small earthquakes from January 2019 to October 2020 to determine the dip parameters of the eight fault geometry, and used the Interferometric Synthetic Aperture Radar (InSAR) data processed by Xu et al. (Seismol Res Lett 91(4):1979–1985, 2020) at UCSD to constrain inversion of the fault-slip distribution of both earthquakes. The results showed that all faults were sinistral strike-slips with minor dip-slip components, exception for dextral strike-slip fault F2. Fault-slip mainly occurred at depths of 0–12 km, with a maximum slip of 3.0 m. The F1 fault contained two slip peaks located at 2 km of fault S4 and 6 km of fault S5 depth, the latter being located directly above the Mw7.1hypocenter. Two slip peaks with maximum slip of 1.5 m located 8 and 20 km from the SW endpoint of the F2 fault were also identified, and the latter corresponds to the Mw6.4 earthquake. We also analyzed the influence of different inversion parameters on the fault slip distribution, and found that the slip momentum smoothing condition was more suitable for the inversion of the earthquakes slip distribution than the stress-drop smoothing condition.

A-optimal design method to determine the regularization parameter of coseismic slip distribution inversion

2020 ◽  
Vol 221 (1) ◽  
pp. 440-450
Author(s):  
Leyang Wang ◽  
Wangwang Gu
Keyword(s):  
Optimal Design ◽  
Regularization Parameter ◽  
Design Method ◽  
Slip Distribution ◽  
Coseismic Slip ◽  
Seismic Slip ◽  
Regularization Parameters ◽  
Curve Method ◽  
Optimal Design Method

ABSTRACT The key to the inversion of a coseismic slip distribution is to determine the regularization parameters. In view of the determination of regularization parameters in seismic slip distribution inversion, the A-optimal design method is proposed in this paper. The L-curve method and A-optimal design method are used to design simulation experiments, and the inversion results show that the A-optimal design method is superior to the L-curve method in determining the regularization parameters. These two methods are also used to determine the regularization parameters of the L'Aquila and Lushan earthquake slip distribution inversions, and the results are consistent with those of other research conducted at home and abroad. Compared with the L-curve method, the A-optimal design method has the advantages of a high accuracy that does not rely on the data fitting accuracy.

scholarly journals Coseismic Deformation and Speculative Seismogenic Fault of the 2017 MS 6.6 Jinghe Earthquake, China, Derived From Sentinel-1 Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Feng ◽  
Zechao Bai ◽  
Jinwei Ren ◽  
Shuaitang Huang ◽  
Lin Zhu
Keyword(s):  
European Space Agency ◽  
Image Data ◽  
Junggar Basin ◽  
Deformation Field ◽  
Slip Distribution ◽  
Coseismic Deformation ◽  
Dislocation Model ◽  
Seismogenic Fault ◽  
Geological Investigation ◽  
Maximum Deformation

A MS 6.6 earthquake struck Jinghe County in Bortala Mongol Autonomous Prefecture of Xinjiang Uygur Autonomous Region on August 9, 2017. The earthquake occurred near the eastern part of the Kusongmuxieke Piedmont Fault (KPF) in the southwest of Junggar Basin. Using two pairs of coseismic SAR image data from the ascending and descending tracks from Sentinel-1 (European Space Agency), we processed the interferograms to obtain the coseismic deformation field. We calculate the fault slip distribution of the earthquake based on the elastic half-space rectangular dislocation model with the available location, geometry from seismic data and the coseismic deformation data. The results show that the earthquake deformation field has the typical characteristics of thrust faulting. The uplift deformation field is about 28 km long and 20 km wide. The maximum displacements of InSAR line-of-sight to the ascending and descending tracks are 49 and 68 mm, respectively. The main slip is concentrated at the depth of 10–20 km. The inverted seismic moment is equivalent to a moment magnitude MW 6.3. This result is very similar to the slip distribution from the seismological inversion. The maximum deformation area and the distribution of aftershocks are both on the west side of the mainshock. They mutually confirm the characteristics of a unilateral rupture. According to stress triggering theory, the aftershocks within 1 month after the mainshock in the layer 10–14 km deep may have been triggered by the mainshock, and the transferred stress increases the seismic risk of the eastern section of the KPF fault. After more than 1 year, a MS 5.4 earthquake occurred to the southwest of the MS 6.6 Jinghe earthquake. Beacause the stress drop change (<0.01 MPa) is too small for the MS 5.4 earthquake to have been directly triggered. Based on the analysis of multisource data and the detailed geological investigation, the thrust Jinghenan fault which north of Kusongmuxieke Piedmont fault is inferred to be the seismogenic fault of the MS 6.6 Jinghe earthquake.

scholarly journals Interplate Slip Distribution Inferred from Co- and Post-seismic Deformation Associated with the 2005 Miyagi-oki Earthquake (M7.2)

2007 ◽  
Vol 59 (4) ◽  
pp. 371-379
Author(s):  
Satoshi MIURA ◽  
Takeshi IINUMA ◽  
Satoshi YUI ◽  
Toshiya SATO ◽  
Kenji TACHIBANA ◽  
...  
Keyword(s):  
Slip Distribution ◽  
Seismic Deformation

scholarly journals Co-seismic slip distribution of the 2011 Tohoku (MW 9.0) earthquake inverted from GPS and space-borne gravimetric data

2018 ◽  
Vol 2 (2) ◽  
pp. 120-138 ◽  
Author(s):  
Xin Zhou ◽  
◽  
Gabriele Cambiotti ◽  
WenKe Sun ◽  
Roberto Sabadini ◽  
...  
Keyword(s):  
Slip Distribution ◽  
Seismic Slip ◽  
Gravimetric Data

scholarly journals Rapid response to the earthquake emergency of May 2012 in the Po Plain, northern Italy

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Milena Moretti ◽  
et al.
Keyword(s):  
Rapid Response ◽  
Seismic Events ◽  
Earthquake Physics ◽  
Po Plain ◽  
Seismic Sequences ◽  
Rupture Length ◽  
Earthquake Detection ◽  
Tectonic Environment ◽  
Seismic Networks ◽  
High Degree

<p>Rapid-response seismic networks are an important element in the response to seismic crises. They temporarily improve the detection performance of permanent monitoring systems during seismic sequences. The improvement in earthquake detection and location capabilities can be important for decision makers to assess the current situation, and can provide invaluable data for scientific studies related to hazard, tectonics and earthquake physics. Aftershocks and the clustering of the locations of seismic events help to characterize the dimensions of the causative fault. Knowing the number, size and timing of the aftershocks or the clustering seismic events can help in the foreseeing of the characteristics of future seismic sequences in the same tectonic environment. Instrumental rapid response requires a high degree of preparedness. A mission in response to a magnitude (Ml) 6 event with a rupture length of a few tens of kilometers might involve the deployment within hours to days of 30-50 seismic stations in the middle of a disaster area of some hundreds of square kilometers, and the installation of an operational center to help in the logistics and communications. When an earthquake strikes in a populated area, which is almost always the case in Italy, driving the relevant seismic response is more difficult. […]</p><br />

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