scholarly journals Interaction Between Historical Earthquakes and the 2021 Mw7.4 Maduo Event and Their Impacts on the Seismic Gap Areas Along the East Kunlun Fault

2021 ◽  
Author(s):  
Peiyu Dong ◽  
Bin Zhao ◽  
Xuejun Qiao
Keyword(s):  
Source Area ◽  
Historical Earthquakes ◽  
Tectonic Stress ◽  
Inhibitory Effect ◽  
Seismic Gap ◽  
Seismogenic Fault ◽  
Qinghai Province ◽  
Coulomb Stress Changes ◽  
Stress Shadow ◽  
Stress Changes

Abstract On May 21, 2021 (UTC time), a Mw7.4 earthquake struck Maduo County, Qinghai Province, China. The rupture of this typical strike-slip event and its aftershocks along the Kunlun-Jiangcuo fault (JCF) propagated approximately 170 km from the epicenter. In this study, we calculated the coseismic and postseismic Coulomb stress changes induced by 14 historical earthquakes and investigated their impacts on the 2021 Maduo source area. We found that the JCF is in the stress shadow of these historical events with a combined ΔCFS range of approximately -0.4 to -0.2 MPa. Since the seismogenic fault of the 1937 event is nearly parallel and close to the JCF, the rupture of the 1937 event had the greatest inhibitory effect on Maduo source area. We hypothesize that the actual loading rate at the depth of the seismogenic layer in the Maduo source area is much higher than the simulated value (0.3 kPa/a). Consequently, the Maduo earthquake still occurred despite the considerable delaying effect of these historical earthquakes (especially the 1937 event). Our findings also indicate that the tectonic stress in the eastern Bayanhar block is still rapidly accumulating and adjusting. Our investigation further reveals the enhanced stress induced by the historical and Maduo events with ΔCFS values of approximately 30~300 kPa and 50~300 kPa on the XDS and the eastern end of the EKF, respectively, not only on the MMS but also at the eastern end of each branch segment of the EKF. Hence, considering the accumulation of tectonic stress, we suggest that the seismic hazard in these two regions has been promoted.

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.

A modified Coulomb failure seismicity model to study earthquake occurrence and frequency-magnitude distributions

2021 ◽  
Author(s):  
Torsten Dahm
Keyword(s):  
Tectonic Stress ◽  
Time Dependent ◽  
New Model ◽  
Coulomb Stress Changes ◽  
Stress Effects ◽  
Effective Media ◽  
Aftershock Sequences ◽  
Stress Changes ◽  
Coulomb Failure ◽  
Frequency Magnitude

<p>The linear Coulomb failure (LCM) and the rate-and-state model (RSM) are two widely-used physics-based seismicity models both assuming Coulomb stress changes acting on pre-existing populations of faults. While both predict background earthquake rates and time-dependent stress effects, only the RSM can additionally explain the time-dependent triggering of aftershocks.</p><p>We develop a modified effective media Coulomb model which accounts for the possibility of earthquake nucleation and retarded triggering of rupture. The new model has only two independent parameters and explains all statistical features of seismicity equally well as the RMS, but is simpler in its concept and provides insights in the possible nature of time-dependent frequency-magnitude distributions. Some of the statistical predictions are different compared to the RSM or LCM. For instance, the model domain is not limited to positive earthquake background or stressing rates; it can also simulate seismicity under zero stressing assumptions. The increase of background seismicity with tectonic stressing is nonlinear, different to the other models, and may even saturate if the tectonic stress loading is very strong. The Omori aftershock decay is predicted in the new model with an exponent of p=1 also for time periods much larger than the aftershock decay time, however, the productivity factor K is time dependent with a very slow exponential attenuation. The attenuation may explain the apparent variation of p in observed aftershock sequences. Interesting is also that the new model predicts a co-seismic peak of triggered aftershocks, which depends on the magnitude of the stress step and does not influence the attenuation of aftershocks following the stress step. It could be a physical explanation for the c-value in Omori’s law, the origin of which is still under discussion.</p><p>We compare the new model to RSM and LCM and discuss the possible implications for earthquake clustering and frequency magnitude distributions.</p>

scholarly journals Locking Status and Earthquake Potential Hazard along the Middle-South Xianshuihe Fault

2018 ◽  
Vol 10 (12) ◽  
pp. 2048 ◽  
Author(s):  
Rumeng Guo ◽  
Yong Zheng ◽  
Wen Tian ◽  
Jianqiao Xu ◽  
Wenting Zhang
Keyword(s):  
Slip Rate ◽  
Relaxation Effect ◽  
Historical Earthquakes ◽  
Coulomb Stress ◽  
Deformation Model ◽  
Potential Hazard ◽  
Viscoelastic Deformation ◽  
Strong Earthquakes ◽  
Coulomb Stress Changes ◽  
Stress Changes

By combining the seismogenic environment, seismic recurrence periods of strong historical earthquakes, precise locations of small–moderate earthquakes, and Coulomb stress changes of moderate–strong earthquakes, we analyze the potential locking status of a seismically quiet segment of Xianshuihe fault between Daofu County and Kangding City (SDK). The interseismic surface velocities between 1999 and 2017 are obtained from updated global positioning system (GPS) observations in this region. After removing the post-seismic relaxation effect caused by the 2008 Mw 7.9 Wenchuan earthquake that occurred around the fault segment, the observed velocities reveal a pronounced symmetric slip pattern along the SDK trace. The far field slip rate is 7.8 ± 0.4 mm/a, and the fault SDK is confirmed to be in an interseismic silent phase. The optimal locking depth is estimated at 7 km, which is perfectly distributed on the upper edge of the relocated hypocenters. A moment deficit analysis shows cumulative seismic moment between 1955 and 2018, corresponding to an Mw 6.6 event. Finally, based on a viscoelastic deformation model, we find that moderate–strong earthquakes in the surrounding area increase the Coulomb stress level by up to 2 bars on the SDK, significantly enhancing the future seismic potential.

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 Geometry and Mechanism of the Mw 5.7 Nakchu Earthquake in Tibet Inferred from InSAR Observations and Stress Measurements

2021 ◽  
Vol 13 (24) ◽  
pp. 5142
Author(s):  
Yujiang Li ◽  
Yongsheng Li ◽  
Xingping Hu ◽  
Haoqing Liu
Keyword(s):  
Focal Mechanism ◽  
Historical Earthquakes ◽  
Tectonic Stress ◽  
Indian Plate ◽  
Coseismic Deformation ◽  
Normal Faulting ◽  
Eurasian Plate ◽  
Seismogenic Fault ◽  
Stress Measurements ◽  
Focal Mechanism Solutions

Different types of focal mechanism solutions for the 19 March 2021 Mw 5.7 Nakchu earthquake, Tibet, limit our understanding of this earthquake’s seismogenic mechanism and geodynamic process. In this study, the coseismic deformation field was determined and the geometric parameters of the seismogenic fault were inverted via Interferometric Synthetic Aperture Radar (InSAR) processing of Sentinel-1 data. The inversion results show that the focal mechanism solutions of the Nakchu earthquake are 237°/69°/−70° (strike/dip/rake), indicating that the seismogenic fault is a NEE-trending, NW-dipping fault dominated by the normal faulting with minor sinistral strike-slip components. The regional tectonic stress field derived from the in-situ stress measurements shows that the orientation of maximum principal compressive stress around the epicenter of the Nakchu earthquake is NNE, subparallel to the fault strike, which controlled the dominant normal faulting. The occurrence of seven M ≥ 7.0 historical earthquakes since the M 7.0 Shenza earthquake in 1934 caused a stress increase of 1.16 × 105 Pa at the hypocenter, which significantly advanced the occurrence of the Nakchu earthquake. Based on a comprehensive analysis of stress fields and focal mechanisms of the Nakchu earthquake, we propose that the dominated normal faulting occurs to accommodate the NE-trending compression of the Indian Plate to the Eurasian Plate and the strong historical earthquakes hastened the process. These results provide a theoretical basis for understanding the geometry and mechanics of the seismogenic fault that produced the Nakchu earthquake.

Preliminary Report on the 18 May 2020 Ms 5.0 Qiaojia Earthquake, Yunnan, China

2021 ◽  
Author(s):  
Zhen Fu ◽  
Changsheng Jiang ◽  
Fengling Yin ◽  
Lei Zhang ◽  
Xuanye Shen ◽  
...  
Keyword(s):  
Stress Field ◽  
Focal Mechanism ◽  
Negative Impact ◽  
Earthquake Hazard ◽  
Focal Mechanisms ◽  
Seismogenic Fault ◽  
Coulomb Stress Changes ◽  
Ludian Earthquake ◽  
Moderate Earthquake ◽  
Stress Changes

Abstract The 18 May 2020 Ms 5.0 Qiaojia earthquake occurred in Qiaojia County, Yunnan Province, ∼25  km away from the 3 August 2014 Ms 6.5 Ludian earthquake. This earthquake was well recorded by dense local seismic stations of the Qiaojia array constructed near the Xiaojiang fault zone. The focal mechanism of the mainshock exhibited strike-slip motion with a centroid depth of 8 km. We determined the seismogenic fault of the Qiaojia earthquake using aftershock relocation with local dense seismic arrays. The mainshock is located on a previously unmapped fault. Aftershocks clearly delineated east–west rupture plane, which was not revealed by the regional seismic network due to relatively sparse stations. The length and width of the aftershock zone are ∼5  km and 3 km, respectively. The focal mechanisms of 70 aftershocks with magnitudes ML≥1.0 showed similar focal mechanism with the mainshock. The stress field inverted from focal mechanisms of the aftershocks is consistent with the tectonic stress field. The coseismic and postseismic static coulomb stress changes show that the Ludian earthquake has a negative impact on the Qiaojia earthquake with a value of −0.01  MPa, implying that the Qiaojia earthquake was unlikely statically triggered by the Ludian earthquake. The Qiaojia earthquake sequence was characterized by low b-value and low-decay rate in the aftershock area, indicating high-seismic risk in this region. The dense seismic observation allows us to study the moderate earthquake in detail and provides us with valuable information of near-fault seismicity to analyze earthquake hazard and the potential of large earthquakes in the future.

Stress modulation of the seismic gap between the 2008 Ms 8.0 Wenchuan earthquake and the 2013 Ms 7.0 Lushan earthquake and implications for seismic hazard

2020 ◽  
Vol 221 (3) ◽  
pp. 2113-2125
Author(s):  
Rumeng Guo ◽  
Yong Zheng ◽  
Jianqiao Xu
Keyword(s):  
Wenchuan Earthquake ◽  
Historical Earthquakes ◽  
Lushan Earthquake ◽  
Seismic Gap ◽  
Longmenshan Fault Zone ◽  
Stress Shadow ◽  
The Wenchuan Earthquake ◽  
Coulomb Failure ◽  
Longmenshan Fault ◽  
Positive Peak

SUMMARY Between 2008 and 2013, the Ms 8.0 Wenchuan earthquake and the Ms 7.0 Lushan earthquake occurred successively in the Longmenshan fault zone. Their aftershocks delineated a prominent seismic gap approximately 50 km long, hereafter referred to as the WLSG. The possibility of an event of Ms 7.0 or above occurring in the WLSG is a matter of great concern. In this study, we estimated the change of Coulomb failure stress (ΔCFS) along the WLSG caused by historical earthquakes in the last 300 yr. Our results revealed that 20 major earthquakes cast a stress shadow on the WLSG before 2008 (−148.7 to −7.0 kPa), hindering the rupture of the Wenchuan earthquake and the Lushan earthquake. The Wenchuan earthquake had an important influence on the stress redistribution of the WLSG, resulting in significant stress increase (14.7 to 337.5 kPa). As of 2018, although the negative ΔCFS caused by historical earthquakes (especially the Dayi earthquake) pushed the southern end of the WLSG away from failure, the positive peak ΔCFS of 323.0 kPa greatly encouraged the rupture of the northern WLSG. The small afterslip and weak microseismicity indicate that the WLSG is a stress barrier with high seismic potential, which can explain the mechanism of rupture termination of the Wenchuan earthquake and the Lushan earthquake.

scholarly journals Coulomb static stress changes before and after the 23 October 2011 Van, eastern Turkey, earthquake (<i>M</i><sub>W</sub>= 7.1): implications for the earthquake hazard mitigation

2013 ◽  
Vol 13 (7) ◽  
pp. 1889-1902 ◽  
Author(s):  
M. Utkucu ◽  
H. Durmuş ◽  
H. Yalçın ◽  
E. Budakoğlu ◽  
E. Işık
Keyword(s):  
Earthquake Hazard ◽  
Aftershock Sequence ◽  
Coulomb Stress ◽  
Van Earthquake ◽  
Coulomb Stress Changes ◽  
Stress Shadow ◽  
Eastern Turkey ◽  
Stress Changes ◽  
Before And After ◽  
2011 Van Earthquake

Abstract. Coulomb stress changes before and after the 23 October 2011 Van, eastern Turkey, earthquake have been analysed using available data related to the background and the aftershock seismicity and the source faults. The coseismic stress changes of the background seismicity had slightly promoted stress over the rupture plane of the 2011 Van earthquake, while it yielded a stress shadow over the Gürpı nar Fault which has been argued to have produced the 7 April 1646 Van earthquake. The stress shadow over the Gürp\\i nar fault has become more pronounced following the occurrence of the 2011 Van earthquake, meaning that the repetition of the 1646 Van earthquake has been further suppressed. Spatial distribution and source mechanisms of the 2011 Van earthquake's aftershocks have been utilised to define four clusters with regard to their relative location to the mainshock rupture. In addition, the aftershock sequence covers a much broader area toward the northeast. Correlations between the observed spatial patterns of the aftershocks and the coseismic Coulomb stress changes caused by the mainshock are determined by calculating the stress changes over both optimally oriented and specified fault planes. It is shown here that there is an apparent correlation between the mainshock stress changes and the observed spatial pattern of the aftershock occurrence, demonstrating the usefulness of the stress maps in constraining the likely locations of the upcoming aftershocks and mitigating earthquake hazard.

scholarly journals Stress Accumulation and Earthquake Activity on the Great Sumatran Fault, Indonesia

2022 ◽  
Author(s):  
Muhammad Taufiq Rafie ◽  
David P. Sahara ◽  
Phil R. Cummins ◽  
Wahyu Triyoso ◽  
Sri Widiyantoro
Keyword(s):  
Time Evolution ◽  
Slip Rate ◽  
Tectonic Stress ◽  
Coulomb Stress ◽  
Earthquake Activity ◽  
Coulomb Stress Changes ◽  
Megathrust Earthquakes ◽  
Stress Changes ◽  
Sumatran Fault ◽  
Stress Accumulation

Abstract The seismically active Sumatra subduction zone has generated some of the largest earthquakes in the instrumental record, and both historical accounts and paleogeodetic coral studies indicate such activity has historical recorded megathrust earthquakes and transferred stress to the surrounding, including the Great Sumatran Fault (GSF). Therefore, evaluating the stress transfer from these large subduction earthquakes could delineate the highly stressed area as potential-earthquake region along the GSF. In this study, we investigated eight megathrust earthquakes from 1797 to 2010 and resolved the accumulated Coulomb stress changes onto the 18 segments along the GSF. Additionally, we also estimated the rate of tectonic stress on the GSF segments which experienced large earthquake using the case of: (1) no sliver movement and (2) with sliver movement. Based on the historical stress changes of large earthquakes and the increase in tectonic stress rate, we analysed the historical stress changes time evolution on the GSF. The Coulomb stress accumulation of megathrust earthquakes between 1797-1907 increase the stress changes mainly on the southern part of GSF which followed by four major events between 1890-1943. The estimation of tectonic stress rates using case (1) produces low rate and long recurrence intervals which implies that the megathrust earthquakes plays an important role in allowing the GSF earthquake to occur. When implementing the arc-parallel sliver movement of case (2) to the calculation, the tectonic stress rates is 9 to 58 times higher than case (1) of no sliver movement. The observed slip rate of 15-16 mm/yr at the GSF is consistent with the recurrence interval for full-segment rupture of 100-200 years obtained from case (2). This suggests that the GSF earthquake is more controlled by the rapid arc-parallel forearc sliver motion. Furthermore, the analysis of stress changes time evolution model shows that some segments such as Tripa (North and South), Angkola, Musi and Manna appear to be brought back in their seismic cycles since these segments have experienced full-segment rupture and likely locked, increasing their earthquake hazard potentials.

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