Modeling of strong ground motions for 1991 Uttarkashi, 1999 Chamoli earthquakes, and a hypothetical great earthquake in Garhwal–Kumaun Himalaya

Chopra, Sumer; Kumar, Vikas; Suthar, Anup; Kumar, Pankaj

doi:10.1007/s11069-012-0289-z

Cited by 36 publications

(8 citation statements)

References 38 publications

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“…In this article, we have made an attempt to reproduce the time histories by using the already-reported parameters required for simulation such as medium properties in terms of quality factor published in various literature works. An average value of the attenuation property of the medium, that is, quality factor (Q s 130.4*(f 0.998 ) (Knopoff, 1964) reported by many studies (see Gupta and Kumar, 2002;Parvez et al, 2003, Joshi, 2006a2006b;Chopra et al, 2012;Sharma et al, 2014;Harinarayan and Kumar, 2018) for Western Himalayas is used and found reliable to reproduce the strong ground motion (herein after SGM) in good agreement with the observed data. We emphasize that averaging the parameter values from many studies that focused on the same region will reduce the associated error of the parameters and deliver the optimum values useful for the modeling.…”

Section: Introductionsupporting

confidence: 60%

“…We estimated the suitable stress drop values for both the earthquakes by generating a number of time histories and comparing the RMS error for each value of stress drop between the observed and predicted PGA values. The stress drop Joshi, 2006aJoshi, , 2006bChopra et al, 2012;Sharma et al, 2014. This study also emphasizes the contribution from the local site effect. The local site effect is proposed to obtain empirically which generally shows very large variations as compared to the source and medium properties.…”

Section: Introductionmentioning

confidence: 56%

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Stochastic Simulation of Strong Ground Motions From Two M > 5 Uttarakhand Earthquakes

et al. 2021

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Many studies based on the geodetic data and statistical analysis of seismicity have pointed out that sufficient amount of stress accumulated in the Himalayan plate boundary may host a big earthquake. Consequently, high seismic activities and infrastructural developments in the major cities around Himalayan regions are always of major concern. The ground motion parameter estimation plays a vital role in the near real time evaluation of potentially damaged areas and helps in mitigating the seismic hazard. Therefore, keeping in mind the importance of estimation of ground motion parameters, we targeted two moderate-size earthquakes that occurred recently within a gap of 10 months in Uttarakhand region with M > 5.0 on 06/02/2017 and 06/12/2017. The ground motions are simulated by adopting a stochastic modeling technique. The source is assumed as ω−2, a circular point source (Brune’s model). The average value of reported anelastic attenuation from various studies, the quality factor, Qs = 130.4*(f0.996), and stress drop values obtained through iterative procedure are considered for simulations. The stochastic spectra are generated between 0.1 and 10 Hz of frequency range. The site effect is also estimated by using the H/V method in the same frequency range. The synthetic spectra are compared with the observed Fourier amplitude spectra obtained from the recorded waveform data and converted back to the time histories. The stochastic time histories are compared with the observed waveforms and discussed in terms of amplitude (PGA). The simulated and observed response spectra at different structural periods are also discussed. The mismatch between the observed and simulated PGA values along with the GMPE existing for shallow crustal earthquakes is also discussed in the present work.

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Section: Introductionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 56%

Stochastic Simulation of Strong Ground Motions From Two M > 5 Uttarakhand Earthquakes

et al. 2021

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“…Moreover, the simulated PGA values are compared with earlier studies for the same region using the correlation coefficient (r) as shown in figure 6. (Chopra et al 2012;Sharma et al 2013;Sharma and Bungum 2006). Isoacceleration maps for all the three possible locations of mainshock have been developed using simulated records at every corner of the grid (figures 7-9).…”

Section: Resultsmentioning

confidence: 99%

“…Black dots represent the epicentre of the earthquakes of Mw> 4. MCT, Main Central Thrust; MBT, Main Boundary Thrust; HFT, Himalayan Frontal Thrust (map modified afterChopra et al 2012).…”

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confidence: 99%

Modelling of strong motion generation areas for a great earthquake in central seismic gap region of Himalayas using the modified semi-empirical approach

et al. 2019

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Over the past decades, strong motion generation areas (SMGAs) have received significant attention in the modelling of high-frequency records. Herein, we propose the source model for a scenario earthquake (M w 8.5) in the central seismic gap region of Himalayas. On the rupture plane, three SMGAs have been identified. Further, SMGA parameters are evaluated using available empirical relations. The spatiotemporal distribution of aftershocks is utilised to locate these SMGAs on the rupture plane. Further, the modified semi-empirical technique (MSET) is used to simulate the strong motion records. It has been observed that the study area can expect peak ground acceleration of >100 cm/s 2 and its distribution is mainly affected by the location of nucleation point in the rupture plane. Furthermore, the estimated peak ground acceleration (PGA) values are comparable with the earlier studies in the region. This confirms the robustness of generated rupture model with three SMGAs and the reliability of MSET to simulate high-frequency records.

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“…The instrument corrected horizontal north-south and east-west components of the waveforms at each station were rotated to acquire radial and transverse components respectively (Sri Ram et al, 2005;Kayal et al, 2009). Following Parvez et al (2011), the attenuation correction was made through 'Q' and 'n' parameters and the near surface attenuation correction was made through kappa value of 0.04 of Chopra et al (2012). For the estimation of source parameters the SPEC module inbuilt in Seisan Software was used.…”

Section: B Source Parametersmentioning

confidence: 99%

Spectral Analysis and Waveform Modelling of Jangalwar Earthquake (Mw 4.1), Chenab Valley, Jammu

Pandey¹,

Puri²,

Bhat³

et al. 2020

JSR

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An earthquake of M w 4.1 occurred in the Jangalwar area of Chenab valley of Jammu and Kashmir on 29 th May, 2017. This earthquake occurred within the source zone of the Jangalwar earthquake of 2013 (M w 5.7) which was followed by aftershocks for about two months. The current paper presents results on spectral analysis and waveform modelling of this earthquake. Its epicenter was located at 33.110 o N, 75.896 o E between the Panjal Thrust and Kishtwar Window. From the travel time and waveform inversion, focal depth of the event was located at 11 km. The estimated seismic moment was calculated at 15.4 dyne-cm, source radius of 0.585 km, moment magnitude 4.1, corner frequency of 2.39 Hz and stress drop of 50.6 bars. The focal plane solution of the event indicates thrust movement with the fault plane strike of 323 o , dip 39 o and rake 100 o . The source fault of the event appears synthetic to NW-SE striking Panjal Thrust. This current activity may be related to reactivation of ramp emanating from the decollement or emergence of a new splay from the Panjal Thrust.

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Modeling of strong ground motions for 1991 Uttarkashi, 1999 Chamoli earthquakes, and a hypothetical great earthquake in Garhwal–Kumaun Himalaya

Cited by 36 publications

References 38 publications

Stochastic Simulation of Strong Ground Motions From Two M > 5 Uttarakhand Earthquakes

Stochastic Simulation of Strong Ground Motions From Two M > 5 Uttarakhand Earthquakes

Modelling of strong motion generation areas for a great earthquake in central seismic gap region of Himalayas using the modified semi-empirical approach

Spectral Analysis and Waveform Modelling of Jangalwar Earthquake (Mw 4.1), Chenab Valley, Jammu

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