scholarly journals Is the Aftershock Zone Area a Good Proxy for the Mainshock Rupture Area?

2020 ◽  
Author(s):  
Jing Ci Neo ◽  
Yihe Huang ◽  
Dongdong Yao ◽  
Shengji Wei
Keyword(s):  
Stress Change ◽  
Coulomb Stress ◽  
Coulomb Stress Change ◽  
Earthquake Relocation ◽  
Aftershock Distribution ◽  
Rupture Area ◽  
Recent Developments ◽  
Similar Range ◽  
Good Proxy ◽  
Postseismic Slip

ABSTRACT The locations of aftershocks are often observed to be on the same fault plane as the mainshock and used as proxies for its rupture area. Recent developments in earthquake relocation techniques have led to great improvements in the accuracy of earthquake locations, offering an unprecedented opportunity to quantify both the aftershock distribution and the mainshock rupture area. In this study, we design a consistent approach to calculate the area enclosed by aftershocks of 12 Mw≥5.4 mainshocks in California, normalized by the mainshock rupture area derived from slip contours. We also investigate the Coulomb stress change from mainshock slip and compare it with the aftershock zone. We find that overall, the ratios of aftershock zone area to mainshock rupture area, hereinafter referred to as “aftershock ratio”, lie within a range of 0.5–5.4, with most values being larger than 1. Using different slip-inversion models for the same mainshock can have a large impact on the results, but the ratios estimated from both the relocated catalogs and Advanced National Seismic System catalog have similar patterns. The aftershock ratios based on relocated catalogs of southern California fall between 0.5 and 4.3, whereas they exhibit a wider range from 1 to 5.4 for northern California. Aftershock ratios for the early aftershock window (within one-day) show a similar range but of smaller values than using the entire aftershock duration, and we propose that continuing afterslip could contribute to the expanding aftershock zone area following several mainshocks. Our results show that areas with positive Coulomb stress change scale with aftershock zone areas, and spatial distribution of aftershocks represents stress release from mainshock rupture and continuing postseismic slip.

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 Coulomb Stress Change in Ahar-Varzaghan (20121108) Earth Quakes

2021 ◽  
Author(s):  
Omid Memarian Sorkhabi
Keyword(s):  
Surface Stress ◽  
Surface Displacement ◽  
Stress Change ◽  
Coulomb Stress ◽  
Stress And Strain ◽  
Average Depth ◽  
Coulomb Stress Change ◽  
Fault Movement ◽  
Coulomb Stress Changes ◽  
Stress Changes

Abstract Understanding how the movement of faults and deformation affects such as motion-induced surface stress and strain, which is very important in seismic regions. The best way to learn about the effects of fault movement is modeled. For example, the modeling of surface displacement or deformation and the amount of damage earthquake can be estimated by the model. Coulomb stress changes can be modeled or predicted earthquake aftershocks or future Earthquakes. we employ assumptions on the orientations, rupture lengths and average slip associated with each earthquake to calculate stress changes. Using this model, we displacement, stress and strain at any depth in the Earth's surface acquired. In this study the modeling of earthquakes Mw= 6.5, Mw=6.3 Ahar-Varzaghan. The earthquakes induced displacements, strains and stresses were calculated at the surface at an average depth and its aftershocks for 10-km Ahar and 4 km Varzaghan.

scholarly journals Fault Instability and Its Relation to Static Coulomb Failure Stress Change in the 2016 Mw 6.5 Pidie Jaya Earthquake, Aceh, Indonesia

2021 ◽  
Vol 8 ◽  
Author(s):  
Dian Kusumawati ◽  
David P. Sahara ◽  
Sri Widiyantoro ◽  
Andri Dian Nugraha ◽  
Muzli Muzli ◽  
...  
Keyword(s):  
Fault Plane ◽  
Fault Analysis ◽  
Stress Change ◽  
Instability Criterion ◽  
Coulomb Stress Change ◽  
Instability Analysis ◽  
Aftershock Distribution ◽  
Coulomb Failure Stress Change ◽  
Coulomb Failure ◽  
Sumatran Fault

Herein, we applied the fault instability criterion and integrated it with the static Coulomb stress change (ΔCFS) to infer the mechanism of the 2016 Mw 6.5 Pidie Jaya earthquake and its aftershock distribution. Several possible causative faults have been proposed; however, the existence of a nearby occurrence, the 1967 mb 6.1 event, created obscurity. Hence, we applied the fault instability analysis to the Pidie Jaya earthquake 1) to corroborate the Pidie Jaya causative fault analysis and 2) to analyze the correlation between ΔCFS distribution imparted by the mainshock and the fault instability of the reactivated fault planes derived from the focal solution of the Pidie Jaya aftershocks. We performed the fault instability analysis for two possible source faults: the Samalanga-Sipopok Fault and the newly inferred Panteraja Fault. Although the maximum instability value of the Samalanga-Sipopok Fault is higher, the dip value of the Panteraja Fault coincides with its optimum instability. Therefore, we concluded that Panteraja was the causative fault plane. Furthermore, a link between the 1967 mb 6.1 event and the 2016 Mw 6.5 earthquake is discussed. To analyze the correlation between the fault instability and the ΔCFS, we resolved the ΔCFS of the Pidie Jaya mainshock on its aftershock planes and compared the ΔCFS results with the fault instability calculation on each aftershock plane. We discussed the possibility of conjugate failure as shown by the aftershock fault instability. Related to the ΔCFS and fault instability comparison, we found that not all the aftershocks have positive ΔCFSs, but their instability value is high. Thus, we suggest that the fault plane instability plays a role in events that do not occur in positive ΔCFS areas. Apart from these, we also showed that the off-Great Sumatran Fault (Panteraja and Samalanga-Sipopok Faults) are unstable in the Sumatra regional stress setting, thereby making it more susceptible to slip movement.

scholarly journals Arah Penyebaran Stress Coulomb pada Batuan akibat Gempabumi Kairatu 26 September 2019

Wahana Fisika ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 62-70
Author(s):  
Harti Umbu Mala ◽  
Juliany N. Mohamad
Keyword(s):  
High Stress ◽  
Stress Change ◽  
Geological Survey ◽  
Coulomb Stress ◽  
Event Data ◽  
Coulomb Stress Change ◽  
United State ◽  
North East ◽  
The North ◽  
Stress Changes

Penelitian ini bertujuan untuk mengetahui arah penyebaran stress batuan yang diakibatkan oleh gempabumi Kairatu dan diduga memiliki keterkaitan dengan kejadian gempabumi yang terjadi setelahnya. Penelitin ini menggunakan data kejadian gempabumi yang diperoleh dari katalog United State Geological Survey (USGS) dan Badan Meteorologi, Klimantologi, dan Geofisika (BMKG) pada tanggal 26 September 2019 dan setelahnya. Adapun metode yang digunakan adalah metode perubahan Coulomb stress menggunakan software Coulomb 3.3. Hasil analisis, menunjukkan bahwa gempabumi Kairatu memiliki mekanisme sumber yakni sesar geser sedikit oblige ke arah barat laut, mengalami peningkatan perubahan stress batuan positif yang dominan ke empat arah yakni utara, timur, selatan dan barat dengan kisaran harga 0,4 – 1,0 bar. Kondisi dengan nilai perubahan stress yang tinggi ini, sangat berpotensi membangkitkan gempabumi susulan dengan kedalaman hiposenter berkisar ≤ 70 km. This research aims to study the direction of the coulomb stress change caused by the Kairatu earthquake and its influence with earthquake events that occur afterwards. This research uses earthquake event data obtained from the catalog of the United State Geological Survey (USGS) and Badan Meteorologi, Klimantologi dan Geofisika (BMKG) on September 26, 2019. The method used is the Stress Coulomb Change using Coulomb 3.3 software.The results of the analysis, showed that the Kairatu earthquake had a sourceof focal mechanism is shear fault oblige to northwestward. It has increasing positive stress changes that dominant to the north, east, south and west directions with the range 0.4 - 1.0 bar. This conditions that have high stress changes are very make possible to triggering earthquake after the main earthquake occurred with the hypocenter ≤ 70 km. Kata kunci: Earthquake; Coulomb Stress Change; Kairatu.

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