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Evolution of Coulomb failure stress in Sulaiman Lobe,Pakistan,and its implications for seismic hazard assessment

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Earth and Planetary Physics 2023年第2期7卷 282-294页

作者： Aiza Amjad Muhammad Shahid Riaz Urooj Shakir Muhammad Younis Khan Muhammad Ali Shah Bahria School of Engineering and Applied Sciences H-11 CampusBahriaBahria UniversityIslamabadPakistan Centre for earthquake Studies National Centre for PhysicsIslamabadPakistan National Centre of Excellence in Geology University of PeshawarPeshawarPakistan GIS and Space Applications in Geosciences(G-SAG)Lab National Center of GIS and Space Applications(NCGSA)IslamabadPakistan

In this research work,we present the evolution of Coulomb failure stress(CFS)in the Sulaiman Lobe and its implications for seismic hazard assessment.The Chaman transform fault,~1,000 km long,is the major active fault that marks the western boundary between Pakistan and Afghanistan on the Indian Plate.To date,few studies have been conducted to unveil the interactions among earthquakes and the implications of these interactions for seismic hazard assessment in the region.We thoroughly investigated the published and online catalog to construct a sequence of major earthquakes that occurred in this region during the past.The final earthquake sequence was composed of 15 earthquakes of M_(w)≥6.0,beginning with the 1888 earthquake.We used the stress-triggering theory to numerically simulate the evolution of CFS caused by these earthquakes.The numerical results revealed that 8 out of 15earthquakes were triggered by the preceding earthquakes.The earthquakes in 1908,1910,1935,1966,and 1997 were rather independent earthquakes in this sequence.Although the epicenters of the 1975a and 1975b earthquakes were in the stress shadow zone,the partial rupture segments of both these earthquakes were in high-CFS regions.The CFS induced by the 1935 earthquake was notable,as it later triggered the 2008 doublet.Moreover,our results revealed that the northern segment of the Chaman Fault,the southern segment of the Ghazaband Fault,and the northwestern segment of the Urghargai Fault demonstrated a high change in CFS that could trigger seismicity in these regions.The necessary arrangements must therefore be made to mitigate any possible seismic hazards in the region.

关键词： Sulaiman Thrust Sulaiman Lobe Earthquake triggering Coulomb failure stress seismic hazard assessment

Seismogenic Tectonics and Dynamics of the 2011 Ms5.9 Yingjiang earthquake in Yunnan, China

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Acta Geologica Sinica(English Edition) 2014年第2期88卷 468-482页

作者： SUN Yao AN Meijian FENG Mei LONG Changxing YANG Zhenyu Institute of Geomechanics Chinese Academy of Geological Sciences

In the southern South-North Seismic Zone,China,seismic activity in the Yingjiang area of western Yunnan increased from December 2010,and eventually a destructive earthquake of Ms5.9 occurred near Yingjiang town on 10 March 2011.The focal mechanism and hypocenter location of the mainshock suggest that the Dayingjiang Fault was the site of the mainshock rupture.However,most of foreshocks and all aftershocks recorded by a portable seismic array located close to the mainshock occurred along the N-S-striking Sudian Fault,indicating that this fault had an important influence on these shocks.Coulomb stress calculations show that three strong （magnitude ≥5.0） earthquakes that occurred in the study region in 2008 increased the coulomb stress along the plane parallel to the Dayingjiang Fault.This supports the Dayingjiang Fault,and not the Sudian Fault,as the seismogenic fault of the 2011 Ms5.9 Yingjiang earthquake.The strong earthquakes in 2008 also increased the Coulomb stress at depths of ≤5 km along the entire Sudian Fault,and by doing so increased the shallow seismic activity along the fault.This explains why the foreshocks and aftershocks of the 2011 Yingjiang earthquake were located mostly on the Sudian Fault where it cuts the shallow crust.The earthquakes at the intersection of the Sudian and Dayingjiang faults are distributed mainly along a belt that dips to the southeast at ～40°,suggesting that the Dayingjiang Fault in the mainshock area also dips to the southeast at ～40°.

关键词： Yingjiang earthquake Dayingjiang fault Sudian fault Earthquake triggering Yunnan

Evolution of cumulative Coulomb failure stress in northeastern Qinghai-Xizang (Tibetan) Plateau and its effect on large earthquake occurrence

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Acta Seismologica Sinica(English Edition) 2007年第2期20卷 117-132页

作者：万永革沈正康曾跃华盛书中 State Key Laboratory of earthquake Dynamics Institute of GeologyChina Earthquake Administration U.S.Geology Survey Golden CO 80401USA Institute of Geophysics China Earthquake Administration

We simulate accumulative Coulomb failure stress change in a layered Maxwell viscoelastic media in the northeastern Qinghai-Xizang （Tibetan） Plateau since 1920. Lithospheric stress/strain evolution is assumed to be driven by dislocations of large earthquakes （M≥7.0） and secular tectonic loading. The earthquake rupture parameters such as the fault rupture length, width, and slip are either adopted from field investigations or estimated from their statistic relationships with the earthquake magnitudes and seismic moments. Our study shows that among 20 large earthquakes （M≥7.0） investigated, 17 occurred in areas where the Coulomb failure stress change is positive, with a triggering rate of 85%. This study provides essential data for the intermediate to long-term likelihood estimation of large earthquakes in the northeastern Tibetan Plateau.

关键词： Earthquake triggering northeastern Tibetan Plateau cumulative Coulomb stress change

A possible mechanism of stimulation of seismic activity by ionizing radiation of solar flares

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earthquake Science 2019年第1期32卷 26-34页

作者： Valery M.Sorokin Alexey K.Yashchenko Victor A.Novikov Pushkov Institute of Terrestrial Magnetism and Radio Wave Propagation of Russian Academy of Sciences TroitskMoscow 108840Russia Joint Institute for High Temperatures of Russian Academy of Sciences Moscow 125412Russia

A possible mechanism of Earthquake triggering by ionizing radiation of solar flares is considered.A theoretical model and results of numerical calculations of disturbance of electric field,electric current,and heat release in lithosphere associated with variation of ionosphere conductivity caused by absorption of ionizing radiation of solar flares are presented.A generation of geomagnetic field disturbances in a range of seconds/tens of seconds is possible as a result of large-scale perturbation of a conductivity of the bottom part of ionosphere in horizontal direction in the presence of external electric field.Amplitude-time characteristics of the geomagnetic disturbance depend upon a perturbation of integral conductivity of ionosphere.Depending on relation between integral Hall and Pedersen conductivities of disturbed ionosphere the oscillating and aperiodic modes of magnetic disturbances may be observed.For strong perturbations of the ionosphere conductivities amplitude of pulsations may obtain^102 nT.In this case the amplitude of horizontal component of electric field on the Earth surface obtains 0.01 mV/m,electric current density in lithosphere-10-6 A/m2,and the power density of heat release produced by the generated current is 10-7 W/m3.It is shown that the absorption of ionizing radiation of solar flares can result in variations of a density of telluric currents in seismogenic faults comparable with a current density generated in the Earth crust by artificial pulsed power systems(geophysical MHD generator"Pamir・2"and electric pulsed facility"ERGU・600"),which provide regional Earthquake triggering and spatiotemporal variation of seismic activity.Therefore,triggering of seismic events is possible not only by man-made pulsed power sources but also by the solar flares.The obtained results may be a physical basis for a novel approach to solve the problem of short・term earthquake prediction based on electromagnetic triggering phenomena.

关键词： solar flare ionosphere telluric current Earthquake triggering

The Nonlinear Influence of Large Celestial Bodies on earthquakes—Short Commentary

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Journal of High Energy Physics, Gravitation and Cosmology 2022年第4期8卷 1032-1036页

作者： Michael Nitsche Z & S Institut Grosselfingen Germany

A new study on the nonlinear interaction of the fluctuating planetary gravitational field with the lithosphere suggests that not only the directly acting gravitational forces are of influence, but mainly higher harmonics of the celestial bodies considered as oscillators on large scales [1]. In the meantime, resonances caused by fluctuating gravity can also be detected on small scales in the laboratory [2].

关键词： Earthquake triggering Planetary Gravity Field Gravitational Field Fluctuations Harmonics

The　stress　field　variation　caused　by　faulting　and　the　prediction　for　seismic　risk

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Acta Seismologica Sinica(English Edition) 1994年第4期7卷 559-566页

作者：赵根模姚兰予马淑芹 Seismological Bureau of Tianjin Municipality Tianjin China

The stress field caused by faulting has an effect on the stability of the neighboring faults, and the study on the fault interaction has a close relation with the prediction of seismic risk. Stress field caused by the rectangle fault in the semi-infinite elastic medium is calculated on the basis of the elastic dislocation theory. The result shows that most of the successive large earthquakes, in the southwestern part of China and North China, occurred in the increasing area of shear stress S(xy) and the decreasing area of normal stress S(yy) The increasing of earthquake occurrence probability has a function relation with the increasing of stress. Earthquake triggering is resulted from the increasing of shear stress and the decreasing of normal stress. An activation coefficient A, of the earthquake is defined to express the change of seismic activity. The concrete risk region can be obtained through space scanning of At value. Finally, the fault interaction in a large scope is discussed in this paper.

关键词： fault interaction variation of stress field Earthquake triggering seismic risk