Research on Static Stress Triggering and Seismicity in Minxian and Adjacent Area, Gansu

2013 ◽  
Vol 477-478 ◽  
pp. 1075-1083
Author(s):  
Fang Bin Liu ◽  
Ai Guo Wang ◽  
Wei Pang
Keyword(s):  
Temporal Evolution ◽  
Elastic Half Space ◽  
Gansu Province ◽  
Adjacent Area ◽  
Strong Earthquakes ◽  
Coulomb Stress Changes ◽  
Space Model ◽  
Stress Changes ◽  
Background Seismicity ◽  
Stress Triggering

On July 22, 2013, an Ms6.6 earthquake occurred in Minxian-Zhangxian, Gansu Province, China, which caused serious damages. Based on Okada's elastic half-space model, we used thrust, strike-slip and thrust-strike as receiver faults respectively to calculate Coulomb stress changes (ΔCFS) of three moderate-strong earthquakes. The results show that the thrust and thrust-strike models are better. More than 90% of aftershocks located in NWW and SEE ,the stress increased areas, which is consistent with strike of Lintan-Tanchang fault (LTF). Therefore, Dieterich’s rate-friction law is used to simulate ΔCFS caused by the activity of the temporal evolution. It shows the seismicity of Minxian and adjacent area is the most frequent and that the distribution of earthquakes is perpendicular to the strike of LTF. The activity degrees vary for the LTF. Tanchang is the strongest, followed by the middle and western, and Minxian is the weakest. Except Minxian, the activities of all areas are above the background seismicity during 300 years and it will be up to the background for 400 years.

Study on Aftershocks Triggering by Static Stress Changes of the Minxian-Zhangxian 6.6 Earthquake

2014 ◽  
Vol 527 ◽  
pp. 77-80
Author(s):  
Fang Bin Liu ◽  
Ai Guo Wang
Keyword(s):  
Main Shock ◽  
Fault Plane ◽  
Elastic Half Space ◽  
Static Stress ◽  
Gansu Province ◽  
Data Sets ◽  
Space Model ◽  
Main Shocks ◽  
Stress Changes ◽  
Better Than

On July 22, 2013, an Ms6.6 earthquake occurred in Minxian-Zhangxian, Gansu Province, China, which caused serious damages. Because of the abundance and clear relationship with the main shocks, aftershocks sequences are typical types of behavior and provide useful data sets. To better understand the aftershocks triggering by static stress changes of the main earthquake, based on Okada’s elastic half-space model, we used accept fault plane consistent with the source and accept fault plane as the optimal models to calculate the stress changes on aftershock focuses by the Minxian-Zhangxian 6.6 Earthquake respectively. The results show that the latter model is better than former, more than 90% of aftershocks located in NWW and SEE, the stress increased areas, which is consistent with strike of Lintan-Tanchang fault (LTF), in other words, the Coulomb static stress changes of the main shock can induce the aftershocks.

scholarly journals Possible triggering of strong earthquakes in a seismic sequence due to Coulomb stress changes generated by the occurrence of previous strong shocks

2001 ◽  
Vol 34 (4) ◽  
pp. 1539
Author(s):  
E. E. PAPADIMITRIOU ◽  
V. G. KARAKOSTAS ◽  
A. B. BABA
Keyword(s):  
Half Space ◽  
Elastic Half Space ◽  
Stress Change ◽  
Coulomb Stress ◽  
Seismic Sequence ◽  
Coseismic Slip ◽  
Strong Earthquakes ◽  
Coulomb Stress Changes ◽  
Stress Changes ◽  
Subsequent Event

Coulomb stress changes (ACFF)were calculated assuming that earthquakes can be modelled as static dislocations in an elastic half-space, and taking into account the coseismic slip in strong earthquakes. The stress change calculations were performed for strike, dip, and rake appropriate to the strong events considered. We evaluate if these chosen earthquakes brought a given strong subsequent event closer to, or farther from, failure. It was found that each of the subsequent strong events occurred in regions of increased calculated Coulomb stress before their occurrence. Moreover, the majority of smaller aftershocks also were located in areas of positive ACFF. This indicates the probable triggering of the latter events, the foci of which are situated at nearby faults or fault segments.

The Stress Triggering of Aftershocks by Badong M5.1 Mainshock from Coulomb Stress Changes

2014 ◽  
Vol 971-973 ◽  
pp. 2172-2175
Author(s):  
Dong Ning Lei ◽  
Jian Chao Wu ◽  
Yong Jian Cai
Keyword(s):  
Stress Change ◽  
Coulomb Stress ◽  
Coulomb Stress Change ◽  
Coulomb Stress Changes ◽  
Stress Changes ◽  
Stress Triggering

TheCoulomb stress changes are usually adopted to make analysis on faultinteractions and stress triggering. This paper mainly deals with Coulomb stresschange of mainshock and affect on aftershocks. We preliminarily conclude thatthe mainshock produce Coulomb stress change on aftershocks most behavingpositive and triggered them. By calculating it is obvious that more aftershocksfell into stress increasing area and triggering percentage is up to ninety ofmaximum and seventy-one of minimum.

scholarly journals Comparative Analysis on Seismicity and Stress Triggering of Strong Earthquakes Sequence in Central Tibet

2021 ◽  
Author(s):  
Gang Yang ◽  
Dongning Lei ◽  
Jianchao Wu
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Relaxation Effect ◽  
Earth Model ◽  
Coulomb Stress ◽  
Maximum Magnitude ◽  
Strong Earthquakes ◽  
Coulomb Stress Changes ◽  
Stress Changes ◽  
Central Tibet

Abstract The Central Tibet constitutes part of the central part of Qinghai-Tibetan Plateau, which is one of the highest seismic activity areas in China. This paper discussed the regularity of seismic activity in this area. Based on a stratified viscoelastic earth model, we calculated the Coulomb stress changes imparted from the 4 strong earthquakes (M≥6.3) the Bengco - southeastern piedmont of Nyainqentanglha mountain fault zone in this region. The result shows that the study area may enter a new active period from 2020. There was a trigger between strong earthquakes (M≥6.3) on the Bengco fault - southeastern piedmont of Nyainqentanglha mountain fault zone. The post-seismic viscous relaxation effect of a strong earthquake had a significant impact on subsequent earthquakes(M≥6.3). In future 100 years, the Coulomb stress loading is more than 1.0 MPa in northwest section of Bengco fault and central of Nimu segment of southeastern piedmont of Nyainqentanglha mountain fault, thence strong earthquakes may occur in this two fault segments. The maximum magnitude of the earthquake will be M6.7 in the future 100 years.

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 Study on Coulomb Stress Triggering of the April 2015 M7.8 Nepal Earthquake Sequence

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jianchao Wu ◽  
Qing Hu ◽  
Weijie Li ◽  
Dongning Lei
Keyword(s):  
Main Shock ◽  
Earthquake Sequence ◽  
Coulomb Stress ◽  
Coulomb Stress Changes ◽  
Nepal Earthquake ◽  
Rupture Plane ◽  
Stress Changes ◽  
Stress Triggering ◽  
Source Models ◽  
Earthquake Sequences

In April 2015, a M7.8 earthquake occurred less than one month before a M7.3 earthquake near Kodari, Nepal. The Nepal earthquake sequences also include four larger (M > 6) aftershocks. To reveal the interrelation between the main shock and the aftershocks, we check the role of coseismic coulomb stress triggering on aftershocks that follow the M7.8 main shock. Based on the focal mechanisms of the aftershocks and source models of the main shock, the coulomb failure stress changes on both of the focal mechanism nodal planes are calculated. In addition, the coulomb stress changes on the focal sources of each aftershock are also calculated. A large proportion of the M > 6 aftershocks occurred in positive coulomb stress areas triggered by the M7.8 main shock. The secondary triggering effect of the M7.3 aftershock is also found in this paper. More specifically, the M7.3 aftershock promoted failure on the rupture plane of the M6.3 aftershock. Therefore, we may conclude that the majority of larger aftershocks, which accumulated positive coulomb stress changes during the sequence, were promoted or triggered by the main shock failure. It suggests that coulomb stress triggering contributed to the evolution of the Nepal M7.8 earthquake sequence.

A Trial Application of Geodetic Data for Inland Fault Assessment – Coulomb Stress Changes Estimated from GNSS Surface Displacements

2018 ◽  
Vol 13 (3) ◽  
pp. 489-495
Author(s):  
Takuya Nishimura ◽  
Keyword(s):  
Standard Method ◽  
Order Approximation ◽  
Active Faults ◽  
Elastic Half Space ◽  
Deformation Source ◽  
Postseismic Deformation ◽  
Dislocation Model ◽  
Coulomb Stress Changes ◽  
Surface Displacements ◽  
Stress Changes

We examine a method to calculate changes in Coulomb failure stress (ΔCFS) from observed GNSS displacements. The method assumes no stress changes on a horizontal plane and a linear elastic relation between strain and stress, represented by Hooke’s law. The ΔCFS distributions calculated using this method are applied to the 2003 Tokachi-oki and the 2016 Kumamoto earthquakes and they are compared with those using a standard dislocation model buried in an elastic half-space. The results suggest that the ΔCFS distribution at a depth of 10 km in a region far from a deformation source can give a first-order approximation using observations of surface displacements. However, ΔCFS distributions near the source cannot be reproduced by the examined method and need to be evaluated using the standard method. We apply the examined method and GNSS displacement data to calculate ΔCFS on major active faults as well as source faults of large inland earthquakes in southwest Japan for the period 1996-2017. ΔCFS from five large earthquakes, including the 2016 Kumamoto earthquake are separately calculated using the standard method with published fault models. Calculated ΔCFS increases by an order of 10 KPa at most faults over the past 21 years. ΔCFS on the source faults for the 2000 Western Tottori, the 2016 Kumamoto, and the 2016 Central Tottori earthquakes reached a maximum just before their rupture. Coseismic and postseismic deformation of the 2011 Tohoku-oki earthquake accelerated an increase of ΔCFS at some faults, including the source fault of the 2016 Central Tottori earthquake and the Arima-Takatsuki fault zone. The examined method can provide information on the activity of inland earthquakes using contemporarily observed deformation, and can hopefully improve the preparedness for earthquakes.

Effects of secondary static stress triggering on the spatial distribution of aftershocks, a case study, 2003 Bam earthquake (SE Iran)

2020 ◽  
Author(s):  
Behnam Maleki Asayesh ◽  
Hamid Zafarani ◽  
Mohammad Tatar
Keyword(s):  
Spatial Distribution ◽  
Static Stress ◽  
Coulomb Stress ◽  
Secondary Stress ◽  
Nodal Plane ◽  
Bam Earthquake ◽  
Coulomb Stress Changes ◽  
Main Shocks ◽  
Stress Changes ◽  
Stress Triggering

<p>Immediate after a large earthquake, accurate prediction of spatial and temporal distribution of aftershocks has a great importance for planning search and rescue activities. Currently, the most sophisticated approach to this goal is probabilistic aftershock hazard assessment (PASHA). Spatial distribution of the aftershocks fallowing moderate to large earthquakes correlate well with the imparted stress due to the mainshock. Furthermore the secondary static stress changes caused by smaller events (aftershocks) could have effect on the triggering of aftershocks and should be considered in the calculations. The 26 December 2003 (Mw 6.6) Bam earthquake with more than 26000 causalities is one of the most destructive events in the recorded history of Iran. This earthquake was an interesting event and was investigated in a majority of aspects. Good variable-slip fault model and precise aftershocks data enabled us to impart Coulomb stress changes due to mainshock and secondary static stress triggering on the nodal planes of aftershocks to learn whether they were brought closer to failure.</p><p>We used recently published high-quality focal mechanisms and hypocenters to reassess the role of small to moderate earthquakes for static stress triggering of aftershocks during the Bam earthquake. By imparting Coulomb stress changes due to the mainshock on the nodal planes of the 158 aftershocks we showed that 77.8% (123 from 158) of the aftershocks received positive stress changes at least in one nodal plane. We also calculated Coulomb stress changes imparted by the mainshock and aftershocks (1≤M≤4.1) onto subsequent aftershocks nodal planes and found that 81.6% (129 of 158) of aftershocks received positive stress changes at least in one nodal plane. In summary, 77.8% of aftershocks are encouraged by the main shocks, while adding secondary stress encourages 81.6%. Therefore, by adding secondary stress the Coulomb Index (CI), the fraction of events that received net positive Coulomb stress changes compared to the total number of events, increased from 0.778 to 0.816.</p>

scholarly journals STRESS INTERACTION BETWEEN THRUST FAULTS ALONG THE SW HELLENIC ARC (GREECE)

2018 ◽  
Vol 40 (1) ◽  
pp. 386
Author(s):  
A. Messini ◽  
E. E. Papadimitriou ◽  
V. G. Karakostas ◽  
I. Baskoutas
Keyword(s):  
Tectonic Stress ◽  
Elastic Half Space ◽  
Coulomb Stress ◽  
Thrust Faults ◽  
Tectonic Plates ◽  
Coulomb Stress Changes ◽  
Seismic Slip ◽  
Hellenic Arc ◽  
Stress Changes ◽  
Major Fault

The occurrence of strong earthquakes (M>6.3) and the evolution of the stress field along the southwestern part of the Hellenic arc since 1959 are examined by the calculation of Coulomb stress changes. The study area is characterized by low angle thrust faults and high seismicity as being part of the subduction interface. Coulomb stress changes were calculated assuming that earthquakes can be modeled as static dislocations in an elastic half-space, considering the co-seismic slip during strong events and the slow tectonic stress build-up along major fault segments due to the movements of the tectonic plates. The ruptures are modeled taking into account the strike, dip, and rake appropriate to each event examined. It is evaluated whether the stress changes brought a given earthquake closer to, or farther away from, failure. It was found that the majority of the events (strong and smaller) are located in stress enhanced areas.

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