scholarly journals Source Model and Stress Disturbance of the 2017 Jiuzhaigou Mw 6.5 Earthquake Constrained by InSAR and GPS Measurements

2018 ◽  
Vol 10 (9) ◽  
pp. 1400 ◽  
Author(s):  
Shunying Hong ◽  
Xin Zhou ◽  
Kui Zhang ◽  
Guojie Meng ◽  
Yanfang Dong ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Source Model ◽  
Descent Method ◽  
Slip Distribution ◽  
Steepest Descent Method ◽  
Nonlinear Inversion ◽  
Fault Geometry ◽  
Seismogenic Fault ◽  
Jiuzhaigou Earthquake ◽  
Geometry Model

Seismogenic fault geometry, especially for a blind fault, is usually difficult to derive, based only on the distribution of aftershocks and interference fringes of Interferometric Synthetic Aperture Radar (InSAR). To better constrain the fault geometry of the 2017 Jiuzhaigou Mw 6.5 earthquake, we first carried out a nonlinear inversion for a single fault source using multi-peak particle swarm optimization (MPSO), Monte Carlo (MC), and Markov Chain Monte Carlo (MCMC) algorithms, respectively, with constraints of InSAR data in multiple SAR viewing geometries. The fault geometry models retrieved with different methods were highly consistent and mutually verifiable, showing that a blind faulting with a strike of ~154° and a dip angle of ~77° was responsible for the Jiuzhaigou earthquake. Based on the optimal fault geometry model, the fault slip distribution jointly inverted from the InSAR and Global Positioning System (GPS) data by the steepest descent method (SDM) and the MC method showed that the slip was mainly concentrated at the depth of 1–15 km, and only one slip center appeared at the depth of 5–9 km with a maximum slip of about 1.06 m, some different from previous studies. Taking the shear modulus of μ = 32 GPa, the seismic moment derived from the distributed slip model was about 7.85 × 1018 Nm, equivalent to Mw 6.54, which was slightly larger than that from the focal mechanism solutions. The fault spatial geometry and slip distribution could be further validated with the spatial patterns of the immediate aftershocks. Most of the off-fault aftershocks with the magnitude > M2 within one year after the mainshock occurred in the stress positive stress change area, which coincided with the stress triggering theory. The static Coulomb stress, triggered by the mainshock, significantly increased at the Tazang fault (northwest to the epicenter), and at the hidden North Huya fault, and partial segments of the Minjiang fault (west of the epicenter).

scholarly journals Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

2020 ◽  
Author(s):  
Pengfei Yu ◽  
Xuejun Qiao ◽  
Wei Xiong ◽  
Wei Chen ◽  
Zhaosheng Nie ◽  
...  
Keyword(s):  
European Space Agency ◽  
Source Model ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Coseismic Deformation ◽  
Seismogenic Fault ◽  
Coulomb Stress Changes ◽  
Rupture Area ◽  
Space Agency ◽  
Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and -4.2 cm for the ascending interferogram and are 7.2 cm and -3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5 ~ 7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688×1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

scholarly journals Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

2020 ◽  
Author(s):  
Pengfei Yu ◽  
Xuejun Qiao ◽  
Wei Xiong ◽  
Wei Chen ◽  
Zhaosheng Nie ◽  
...  
Keyword(s):  
European Space Agency ◽  
Source Model ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Coseismic Deformation ◽  
Seismogenic Fault ◽  
Coulomb Stress Changes ◽  
Rupture Area ◽  
Space Agency ◽  
Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and -4.2 cm for the ascending interferogram and are 7.2 cm and -3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5 ~ 7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688×1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

scholarly journals Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Pengfei Yu ◽  
Xuejun Qiao ◽  
Wei Xiong ◽  
Wei Chen ◽  
Zhaosheng Nie ◽  
...  
Keyword(s):  
European Space Agency ◽  
Source Model ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Coseismic Deformation ◽  
Seismogenic Fault ◽  
Coulomb Stress Changes ◽  
Rupture Area ◽  
Space Agency ◽  
Stress Changes

Abstract On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and − 4.2 cm for the ascending interferogram and are 7.2 cm and − 3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5–7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688 × 1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

scholarly journals Fault Slip Model of the 2018 Mw 6.6 Hokkaido Eastern Iburi, Japan, Earthquake Estimated from Satellite Radar and GPS Measurements

2019 ◽  
Vol 11 (14) ◽  
pp. 1667 ◽  
Author(s):  
Zelong Guo ◽  
Yangmao Wen ◽  
Guangyu Xu ◽  
Shuai Wang ◽  
Xiaohang Wang ◽  
...  
Keyword(s):  
Source Parameters ◽  
Fault Slip ◽  
Slip Distribution ◽  
Coseismic Deformation ◽  
Gps Data ◽  
Nonlinear Inversion ◽  
Slip Model ◽  
Seismogenic Fault ◽  
Geometry Model ◽  
Fault Slip Distribution

In this study, Sentinel-1 and Advanced Land Observation Satellite-2 (ALOS-2) interferometric synthetic aperture radar (InSAR) and global positioning system (GPS) data were used to jointly determine the source parameters and fault slip distribution of the Mw 6.6 Hokkaido eastern Iburi, Japan, earthquake that occurred on 5 September 2018. The coseismic deformation map obtained from the ascending and descending Sentinel-1 and ALOS-2 InSAR data and GPS data is consistent with a thrust faulting event. A comparison between the InSAR-observed and GPS-projected line-of-sight (LOS) deformation suggests that descending Sentinel-1 track T046D, descending ALOS-2 track P018D, and ascending ALOS-2 track P112A and GPS data can be used to invert for the source parameters. The results of a nonlinear inversion show that the seismogenic fault is a blind NNW-trending (strike angle ~347.2°), east-dipping (dip angle ~79.6°) thrust fault. On the basis of the optimal fault geometry model, the fault slip distribution jointly inverted from the three datasets reveals that a significant slip area extends 30 km along the strike and 25 km in the downdip direction, and the peak slip magnitude can approach 0.53 m at a depth of 15.5 km. The estimated geodetic moment magnitude released by the distributed slip model is 6.16   × 10 18   N · m , equivalent to an event magnitude of Mw 6.50, which is slightly smaller than the estimates of focal mechanism solutions. According to the Coulomb stress change at the surrounding faults, more attention should be paid to potential earthquake disasters in this region in the near future. In consideration of the possibility of multi-fault rupture and complexity of regional geologic framework, the refined distributed slip and seismogenic mechanism of this deep reverse faulting should be investigated with multi-disciplinary (e.g., geodetic, seismic, and geological) data in further studies.

scholarly journals OPTIMIZATION OF QUANTUM MONTE CARLO WAVE FUNCTION: STEEPEST DESCENT METHOD

2010 ◽  
Vol 21 (04) ◽  
pp. 523-533 ◽  
Author(s):  
M. EBRAHIM FOULAADVAND ◽  
MOHAMMAD ZARENIA
Keyword(s):  
Monte Carlo ◽  
Wave Function ◽  
Quantum Monte Carlo ◽  
Descent Method ◽  
Steepest Descent ◽  
Steepest Descent Method ◽  
Direct Energy Minimization ◽  
Direct Energy ◽  
Spatial Coordinates ◽  
Quantum Monte Carlo Method

We have employed the steepest descent method to optimize the variational groundstate quantum Monte Carlo wave function for He , Li , Be , B and C atoms. We have used both the direct energy minimization and the variance minimization approaches. Our calculations show that in spite of receiving insufficient attention, the steepest descent method can successfully minimize the wave function. All the derivatives of the trial wave function respect to spatial coordinates and variational parameters have been computed analytically. Our groundstate energies are in a very good agreement with those obtained with diffusion quantum Monte Carlo method (DMC) and the exact results.

Solution of inverse coefficient problem for fractional anomalous diffusion equation

2012 ◽  
Vol 9 (2) ◽  
pp. 65-70
Author(s):  
E.V. Karachurina ◽  
S.Yu. Lukashchuk
Keyword(s):  
Anomalous Diffusion ◽  
Fractional Derivatives ◽  
Descent Method ◽  
Extremum Problem ◽  
Steepest Descent Method ◽  
Coefficient Problem ◽  
Caputo Fractional Derivatives ◽  
Inverse Coefficient Problem ◽  
Residual Functional ◽  
Inverse Coefficient

An inverse coefficient problem is considered for time-fractional anomalous diffusion equations with the Riemann-Liouville and Caputo fractional derivatives. A numerical algorithm is proposed for identification of anomalous diffusivity which is considered as a function of concentration. The algorithm is based on transformation of inverse coefficient problem to extremum problem for the residual functional. The steepest descent method is used for numerical solving of this extremum problem. Necessary expressions for calculating gradient of residual functional are presented. The efficiency of the proposed algorithm is illustrated by several test examples.

Inferred fault geometry and slip distribution of the 2010 Jiashian, Taiwan, earthquake is consistent with a thick-skinned deformation model

2011 ◽  
Vol 301 (1-2) ◽  
pp. 78-86 ◽  
Author(s):  
Kuo-En Ching ◽  
Kaj M. Johnson ◽  
Ruey-Juin Rau ◽  
Ray Y. Chuang ◽  
Long-Chen Kuo ◽  
...  
Keyword(s):  
Slip Distribution ◽  
Deformation Model ◽  
Fault Geometry ◽  
Taiwan Earthquake

scholarly journals Improved Immune Algorithm Combined with Steepest Descent Method for Optimal Design of IPMSM for FCEV Traction Motor

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3904
Author(s):  
Ji-Chang Son ◽  
Myung-Ki Baek ◽  
Sang-Hun Park ◽  
Dong-Kuk Lim
Keyword(s):  
Optimal Design ◽  
Permanent Magnet Synchronous Motor ◽  
Torque Ripple ◽  
Descent Method ◽  
Immune Algorithm ◽  
Electric Machines ◽  
Steepest Descent Method ◽  
Superior Performance ◽  
Element Analysis ◽  
Traction Motor

In this paper, an improved immune algorithm (IIA) was proposed for the torque ripple reduction optimal design of an interior permanent magnet synchronous motor (IPMSM) for a fuel cell electric vehicle (FCEV) traction motor. When designing electric machines, both global and local solutions of optimal designs are required as design result should be compared in various aspects, including torque, torque ripple, and cogging torque. To lessen the computational burden of optimization using finite element analysis, the IIA proposes a method to efficiently adjust the generation of additional samples. The superior performance of the IIA was verified through the comparison of optimization results with conventional optimization methods in three mathematical test functions. The optimal design of an IPMSM using the IIA was conducted to verify the applicability in the design of practical electric machines.

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