scholarly journals Coulomb Stress Change of Mw 7.5 Palu-Donggala Earthquake, Sulawesi (28 September 2018)

2020 ◽  
Vol 18 (1) ◽  
pp. 19
Author(s):  
Adhi Wibowo ◽  
Pepen Supendi ◽  
Andri D. Nugraha

The Mw 7.5 Palu earthquake that occurred in Palu-Central Sulawesi, Indonesia, on September 28, 2018, accompanied by the tsunami and liquefaction caused casualties and building damage in the city of Palu and its surroundings. One month later, a series of earthquakes swarm occurred in Mamasa, West Sulawesi. In this study, coulomb stress were calculated using a half-space elastic model in a square plane which is assumed to be homogeneous isotropy to analyze whether there is a relationship between earthquakes that occur in Palu and earthquakes swam in the coulomb stress field changes. The results show that the area that experienced a stress reduction predominantly towards the north and south of the mainshock hypocenter, while the aftershocks were at an increase in coulomb stress changes, so that the Mamasa earthquakes swarm probably have been triggered by the Palu earthquake.

Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos

On August 17<sup>th</sup> 1999, a M<sub>w</sub> 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.


2014 ◽  
Vol 971-973 ◽  
pp. 2172-2175
Author(s):  
Dong Ning Lei ◽  
Jian Chao Wu ◽  
Yong Jian Cai

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.


2021 ◽  
Author(s):  
Omid Memarian Sorkhabi

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.


Wahana Fisika ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 62-70
Author(s):  
Harti Umbu Mala ◽  
Juliany N. Mohamad

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.


Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos

On August 17<sup>th</sup> 1999, a M<sub>w</sub> 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.


2015 ◽  
Vol 5 (1) ◽  
pp. 9 ◽  
Author(s):  
M Madlazim

Coulomb stress change analysis has been applied to understand whether the 2013/07/02 (Mw=6.1) has been triggered by 2013/01/21 earthquake (Mw=6.1) the proximity to failure on the Aceh segment of Sumatra Fault Zone (SFZ). We examine the problem of how one earthquake might trigger another using Coulomb stress changes plotting. To plot the Coulomb stress changes, we used Global CMT data for the both earthquakes and used GEOFON data for manually revised epicenters of its aftershocks. The earthquakes are located on Aceh segment of the historic no recorded large earthquake. Coulomb stress changes modeling of the both earthquakes and plot their aftershocks. Surprisingly, the 2013/07/02 earthquake is located on increasing Coulomb stress changes region of 2013/01/21 earthquake plotting. Here explain that the 2013/07/02 earthquake has been triggered by the 2013/01/21 earthquake. Further, the two aftershocks of the 2013/07/02 earthquake is located on increasing Coulomb stress changes region of 2013/07/02 earthquake plotting. So that, the aftershocks has been triggered by increasing Coulomb stress changes of the 2013/07/02 earthquake.


2021 ◽  
Author(s):  
Omid Memarian Sorkhabi

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.


Author(s):  
Jianjun Wang ◽  
Caijun Xu ◽  
Jeffrey T. Freymueller ◽  
Yangmao Wen ◽  
Zhuohui Xiao

Abstract Coulomb stress change is the change in resultant force of shear stress and friction imposed on a receiver fault plane. The resulting stress change is often computed using the Coulomb 3.4 and the postseismic Green’s functions and postseismic components (PSGRN-PSCMP) programs. Notwithstanding both preferences, both have incomplete optimally oriented failure planes (OOPs) and are inconvenient to resolve Coulomb stress changes on various fault planes placed in varying depths. Here, we present an alternative program termed AutoCoulomb. It leverages the shell command-line tool to automatically batch-process Coulomb stress changes on all sorts of receiver fault planes. We first validate the program. We then apply it to the 2020 Mw 7.8 Simeonof Island, Alaska, earthquake, as a case study. Our results show that Coulomb stress changes resolved on fixed receiver faults, using the three programs, are in line with each other. So are those resolved on 3D OOPs using the PSGRN–PSCMP and the AutoCoulomb programs. Nevertheless, Coulomb stress changes on 2D OOPs, generated by the AutoCoulomb program, always outweigh those done by the Coulomb 3.4 program, indicating that 2D OOPs constrained by the latter are not the most optimal. Some nonoptimal 2D OOPs result in the reversal of the signs of Coulomb stress changes, posing a risk of misleading stress shadows with negative Coulomb stress changes. For the case study, the 28 July 2020 Mw 6.1 aftershock received a positive coseismic Coulomb stress change of ∼3.5 bars. In contrast, the compounded coseismic Coulomb stress changes at the hypocenters of the 1946 Mw 8.2, the 1948 Mw 7.2, and the 2020 Mw 7.8 earthquakes are within a range from −1.1 to 0.1 bar, suggesting that coseismic Coulomb stress changes promoted by preceding mainshocks alone are not responsible for these mainshocks. Other factors, such as postseismic viscoelastic relaxation, afterslip, and slow slip, may contribute to promoting their occurrence.


2021 ◽  
Author(s):  
Hanna Blanck ◽  
Kristín Vogfjörd ◽  
Halldór Geirsson ◽  
Vala Hjörleifsdóttir

&lt;p&gt;From 1993 to 1998, the Hengill volcanic area in SW-Iceland was subjected to a volcano-tectonic event which caused a local uplift of the crust of 8 cm and triggered over 90.000 earthquakes. Relocating a sub-set of 12.000 earthquakes in the direct vicinity of the uplift centre improved resolution and enabled the mapping of 25, mostly NNE-SSW and ENE-WSW oriented sub-vertical groups of earthquake which are interpreted as faults. Focal mechanisms were calculated, using the best fitting plane through a group of earthquakes as additional constraint. Slip on the interpreted faults could be estimated averaging slip of all earthquakes within that group. Most faults show strike-slip movement with a small normal component. Right-lateral slip prevails. We modelled Coulomb stress changes that the uplift would have caused and compared them to out results. The Coulomb stress changes can only explain the observed movement on some of the faults but on others fault movements is impeded, that is, the Coulomb stress change is negative. Varying the location of the uplift within its error margin increases the number of faults on which the observed movement is promoted but the slip on a number of faults remains unexplained. &amp;#160;&lt;/p&gt;


2021 ◽  
Vol 7 (4) ◽  
pp. 593-600
Author(s):  
Matheus Souisa ◽  
Sisca Madonna Sapulete

The Tehoru earthquake occurred due to the release of stress in rocks. There is a release of energy as an earthquake as a result of the rock elasticity limit has been exceeded because the rock is no longer able to withstand the stress. One method to determine the distribution of earthquake stress is the Coulomb stress change method. The study aimed to determine the DCS of the Tehoru earthquake, Seram Island, and the effect of the main earthquake stress release on aftershocks.  The research results show that the DCS distribution of the Tehoru June 16, 2021 earthquake is shown with negative lobes and positive lobes. The negative lobe is found in an area that is perpendicular to the fault plane and has been identified as having experienced relaxation, so there may be still aftershocks with stress values ranging from (0.0 – 0.3) bar. The dominant positive lobe occurs next to the southern end of the fault plane, too much located in the area of increasing Coulomb stress with values ranging from (0.2 - 0.6) bar


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