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a Map shows the aftershocks of Oct 8, 2005 earthquake where the red star indicates the epicenter of the mainshock, b frequency-magnitude distribution (FMD) of aftershocks for t > 0.5 days with b = 1.15 ± 0.06 and magnitude of completeness Mc = 3.7. Triangles and squares represent the number and cumulative number of each individual magnitude level of earthquake, respectively. The line represents the FMD linear regression fitted with the observed data
Source publication
We model the spatial and temporal evolution of
October 8, 2005 Kashmir earthquake’s aftershock activity using the rate-and-state dependent friction model incorporating uncertainties in computed coseismic stress perturbations. We estimated the best possible value for frictional resistance “Aσ
n”, background seismicity rate “r” and coefficient of str...
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Citations
... According to a change in the value , the chains demonstrate the transition from quasiplastic flow to brittle fracture, according to the general interpretation from [6]. Let us note that a number of studies [14,15] mention periodic activations of the after-shock process of the Kashmir earthquake and the impossibility of explaining its without introducing special corrections into the seismodynamic model (in particular, the "slip variability" correction, "repeated slip", etc.) or the assumption of the existence of a highly fluid layer in the lower crust. ...
The GIS-EEDB (the Expert Earthquake Database) and GIS-ENDDB (the Earth’s Natural Disasters DataBase) geoinformation systems implement methods for spatial-temporal analysis of both classical and new characteristics of the seismogeodynamic process. One of the new characteristics is a normalized creepex parameter that can be used in the statistical approach to studying of seismicity to assess a relative contribution of “soft” (creep) and “hard” (explosion) movements to the overall process of focal radiation. In this paper, the following modifications of the creepex parameter are proposed and compared: 1) Cr0 Cr0_world and CrN CrN world as the result of reducing the parameters Cr0 and CrN of each event to the world average values of the creepex, obtained from the polynomial dependence of Cri_world (i = 0, N) on MS_world where Cri_world are calculated based on the world average estimates of Ms_world and mb_world at uniform intervals of the seismic moment (NEIC catalog), 2) Cr_bji as the result of reducing CrN of each event to CrN_bji i.e. to the average for the studied in this work BJI catalog creepex values obtained from the polygonal trend CrN (MS) of all the catalog events. The advantage of using the creepex parameter, reduced to the trend of averaging the magnitudes of the catalog in question, is revealed, since the smallest linear dependence of the creepex on the magnitude is achieved (in comparison with the classical and normalized creepex) and the symmetry in the maximum amplitude of the deviation of the parameter relative to zero is preserved. Examples of the application of the compared parameters in specific seismic-geodynamic studies of aftershock processes of the Molucca and Simushir earthquakes also demonstrate the advantage of the parameter Cr_bji n the observed correspondence of the variations of the latter to the known physical processes in the focal zone of the Kashmir event, studied by the seismic-geodynamic methods of the GIS-EEDB geographical information system.
... Being a prerequisite of seismic hazard analysis, a reliable earthquake catalog is an important ingredient. The computed M c value is 4.9 in the study region, which is greater than the values estimated for Northern Pakistan (Javed et al. 2016). 1995;Bayrak et al. 2002;Legrand et al. 2012;Nuannin et al., 2005;Schorlemmer et al. 2005). ...
... M c value for Northern Pakistan is usually varying from 3.7 to 4.0(Parsons and Segou 2014;Javed et al. 2016). The computed b-value is higher at several portions of the Chaman fault, Southern Ghazaband, and couples of sections of Ornach-Nal fault. ...
The current study analyses the earthquake catalog of Southern Pakistan from 1973 to 2016. The magnitude of completeness (Mc) is 4.9. The b-value and seismic moment release of the Chaman fault system have been calculated and compared with slip rates. The results demonstrate that both seismic moment releases and b-value estimation are consistent with the geodetic slip rates inferred from the InSAR (i.e., lower moment release and higher b-value were estimated on the creep section of the Chaman fault system). The b-value is estimated approximately 1.2 in the northern (i.e., >200 km) and southern (i.e., between 25 and 100 km) portions of Ghazaband fault, which likely depicts the partially creep sections and could not generate large earthquakes. Similarly, the southern Ornach-Nal fault section between 25 and 100 km shows higher b-value (> 1.5), which reflects the creeping nature of the fault. b-value are varied from 0.65 to 1.0 in the region where historic large earthquakes occurred, whereas the b-value is estimated 1.68 for the partial creep section between 110 and 140 km and 2.0 for the creeping section between 210 and 310 km of the Chaman fault. Moreover, b-value of 0.7–1.0 has been found for the central section of both Ornach-Nal and Ghazaband faults. Results reveal that Chaman fault system is likely to host large earthquakes on the section of the faults, which estimate b-value in the range 0.65–1.1 and moderate size earthquakes where b-value is estimated between 1.1 and 1.5. Moreover, faults, which estimate b-value >1.5, are most likely the safe regions from moderate to large earthquakes. In short, estimated b-value clearly depicts the mechanical properties of fault, so that combination of mechanics of fault from geodetic studies and estimated b-value from homogenized earthquake catalog improve the earthquake forecasting models.
... Being a prerequisite of seismic hazard analysis, a reliable earthquake catalog is an important ingredient. The computed M c value is 4.9 in the study region, which is greater than the values estimated for Northern Pakistan (Javed et al. 2016). 1995;Bayrak et al. 2002;Legrand et al. 2012;Nuannin et al., 2005;Schorlemmer et al. 2005). ...
... M c value for Northern Pakistan is usually varying from 3.7 to 4.0(Parsons and Segou 2014;Javed et al. 2016). The computed b-value is higher at several portions of the Chaman fault, Southern Ghazaband, and couples of sections of Ornach-Nal fault. ...
The rapid advancement in ground and space based ionospheric measurements provide an opportunity to work on different earthquake precursors for lithosphere-ionosphere coupling hypothesis. In this paper, the peak plasma ionospheric frequency (foF2) for 90 days before/after the main shock of September 24, 2019 (M5.6) earthquake in Pakistan are studied for earthquake precursors from ionosonde stations located at Islamabad and Sonmiani. We implement the 30 days running median technique to detect the abnormality in foF2 over the epicenter of impending earthquake. A comprehensive analysis of these anomalies on two stations is performed in order to extract the maximum of these abnormalities in their respective regions. The deviation in hourly data in Sonmiani station shows significant variation within 10-20 days before the main shock, as most of the values within 5-10 days’ window are within the confidence limits. On the other hand, positive and negative deviations in the analysis of Islamabad station may be revealed as a possible signature of seismo-ionospheric anomalies. The major reason of these seismo-ionospheric anomalies is the distance between the ionosonde station and epicenter, where Islamabad station is close to the epicenter as compared to Sonmiani. It is noteworthy that both negative and positive deviations are observed before the M5.6 earthquake; however, the intensity of positive anomalies is more than negative anomalies. Moreover, severe positive deviation occurs within 10-20 days before the earthquake at the Sonmiani station. Also, there is no geomagnetic storm within 10 days before the earthquake which opposes the existence of seismo-ionospheric anomalies. The evidence supports that these seismo-ionospheric precursors are probably due to the lithospheric-ionospheric coupling.
... The reported seismic events of moderate magnitude (3.8-4.7) in the area from 1972 to the present are also shown in the map. The catalogue used for plotting the events was a composite of catalogues from USGS and IRIS with a completeness of magnitude of 3.7 (Javed et al. 2016). USGS has an allied recording station called ''NIL'' at Nilore Islamabad. ...
Radon concentration, a geochemical parameter of naturally occurring noble gas and potential relative gravity field variation, has been studied in the current investigations. These investigations were carried out along and in proximity to the Khisor Thrust in the Trans Indus ranges marking the southern boundary of Bannu basin in Pakistan. The studies were aimed to demark the concealed section of the thrust fault beyond termination of its surface signature. The consistent increasing pattern of radon vari-
ation while approaching the approximate located fault and decrease while moving farther from it suggests the existence of a fault to the subsurface, which should be verified through gravity studies. Variation of radon concentration between 2.5 and 4.1 kBq/m3 was observed on or near the fault zone in exposed and concealed segments, whereas the lower bound variation of 1.1–2 kBq/m3 was encountered on points moving away from fault zone. This variation of radon concentration promisingly supported the idea of the
existence of a fault zone beyond the cessation of surface signature. The argument was further validated through the relative gravity variation studies following the radon concentration. The Bouguer anomaly was calculated along all 16 profiles cross-cutting the fault zone. The regional gravity mapped along 231 points of investigation showed a variation between - 90 and 8 mGal. The residual gravity highlighting the effects of upper crust disturbance because of under-thrusting has shown anomalous values between - 11 and 18 mGal. The results when contoured have shown a good congruence with those received from radon concentration contrasts. Conclusively, it can be perceived that these two nondestructive and less laborious techniques work in tandem usefully to delineate the unseen earthquake potential source.
