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>

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 Usefulness of Coulomb Static Stress Changes in Earthquake Hazard Studies: An Example from the Lake Van Area, Eastern Turkey

2021 ◽  
Vol 4 (2) ◽  
pp. 33-41
Author(s):  
Murat Utkucu ◽  
Hatice Durmuş
Keyword(s):  
Earthquake Hazard ◽  
Static Stress ◽  
Coulomb Stress ◽  
Lake Area ◽  
Earthquake Rupture ◽  
Lake Van ◽  
Coulomb Stress Changes ◽  
Calculated Stress ◽  
Stress Changes ◽  
Large Earthquakes

It has been globally documented over different tectonic environments that Coulomb static stress changes caused by a mainshock can promote or demote stresses along the neighboring faults and thus triggers or delays following seismicity. In the present study Coulomb stress changes of the earthquakes in the Lake Van area are calculated using available data and the likely source faults. The calculated stress change maps demonstrate that the large earthquakes in the Lake Area are mostly stressed by the preceding earthquakes, suggesting earthquake rupture interactions. It is further suggested that Coulomb stress maps could be used for constraining the likely locations of the future large earthquakes and in the earthquake hazard mitigation studies.

Static Stress Changes and Triggering Imposed by Wenchuan Earthquake on Lushan M7 Earthquake

2014 ◽  
Vol 597 ◽  
pp. 324-327
Author(s):  
Dong Ning Lei ◽  
Yong Jian Cai ◽  
Heng Li
Keyword(s):  
Wenchuan Earthquake ◽  
Static Stress ◽  
Coulomb Stress ◽  
Stress Increase ◽  
Stress Changes ◽  
Stress Triggering ◽  
Important Field ◽  
Earthquake Event ◽  
Space Stress

Some faults rupture the surface followed by coseismic dislocation, which causes space stress changes and transmits or imposes static stress on or to neighboring faults.The static stress triggering leads to the adjacent fault ruptured in advance, which means a Coulomb stress increase and triggers a new earthquake event. In recent two decades, some studies on stress triggering became important field of seismotectonics. The occurrence of both Wenchuan M8.0 earthquake and Japan M9.0 eathquake have arisen interest of many researchers, and obtained much new result and understanding.

scholarly journals Static stress transfer from the May 20, 2012, M 6.1 Emilia-Romagna (northern Italy) earthquake using a co-seismic slip distribution model

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Athanassios Ganas ◽  
Zafeiria Roumelioti ◽  
Konstantinos Chousianitis
Keyword(s):  
Stress Transfer ◽  
Northern Italy ◽  
Static Stress ◽  
Distribution Model ◽  
Coulomb Stress ◽  
Coulomb Stress Changes ◽  
Seismic Slip ◽  
Seismological Data ◽  
Stress Changes ◽  
Fixed Orientation

<p>We model the static stress transfer for the May 2012 northern Italy earthquakes, assuming that failure of the crust occurs by shear. This allows the mechanics of the process to be approximated by the Okada (1992) expressions for displacement and strain fields due to a finite rectangular source in an elastic, homogeneous and isotropic half-space. The slip model of the May 20, 2012, earthquake was derived using empirical Green’s functions and a least-squares inversion scheme of source time functions computed from regional broadband seismological data. The derived model is then incorporated into the computation of Coulomb stress change (ΔCFF) to investigate the possibility that the May 20, 2012, M 6.1 event triggered the second earthquake that occurred on May 29, 2012 (M 5.9). We calculate the Coulomb stress changes for both: (a) optimally oriented planes to regional compression; and (b) planes of fixed orientation assuming that E-W striking, south-dipping thrust faults of the May 29, 2012, type of rupture was a candidate for failure. In both cases, we find that the triggering is promoted as the ΔCFF values in the hypocentral area of the May 29, 2012, earthquake are positive (between 0.61-0.74 bar).</p><p> </p>

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.

scholarly journals ANALYSING POST-SEISMIC DEFORMATION OF IZMIT EARTHQUAKE WITH INSAR, GNSS AND COULOMB STRESS MODELLING

2016 ◽  
Vol XLI-B1 ◽  
pp. 417-421 ◽  
Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos
Keyword(s):  
Measurement Techniques ◽  
Satellite System ◽  
Northern Region ◽  
Strike Slip ◽  
Coulomb Stress ◽  
North West ◽  
Coulomb Stress Changes ◽  
Izmit Earthquake ◽  
The North ◽  
Stress Changes

On August 17&lt;sup&gt;th&lt;/sup&gt; 1999, a M&lt;sub&gt;w&lt;/sub&gt; 7.4 earthquake struck the city of Izmit in the north-west of Turkey. This event was one of the most devastating earthquakes of the twentieth century. The epicentre of the Izmit earthquake was on the North Anatolian Fault (NAF) which is one of the most active right-lateral strike-slip faults on earth. However, this earthquake offers an opportunity to study how strain is accommodated in an inter-segment region of a large strike slip fault. In order to determine the Izmit earthquake post-seismic effects, the authors modelled Coulomb stress changes of the aftershocks, as well as using the deformation measurement techniques of Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS). The authors have shown that InSAR and GNSS observations over a time period of three months after the earthquake combined with Coulomb Stress Change Modelling can explain the fault zone expansion, as well as the deformation of the northern region of the NAF. It was also found that there is a strong agreement between the InSAR and GNSS results for the post-seismic phases of investigation, with differences less than 2mm, and the standard deviation of the differences is less than 1mm.

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