Deterministic seismic scenarios for North East India

Kanth, S. T. G. Raghu; Dash, Sujit Kumar

doi:10.1007/s10950-009-9158-y

Cited by 31 publications

(6 citation statements)

References 35 publications

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“…Deterministic seismic hazard assessment can be supported from the identification of geologically active structures, whose previous activity can or cannot be evidenced in the usually reduced historic instrumental record (Convertito et al 2006;Cultrera et al 2010;Raghu Kanth and Dash 2010). The San Ramón Fault has been recently identified like a geologically active fault which can produces large magnitude crustal earthquakes, in the range of M w 6.9-7.4 (Armijo et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

et al. 2013

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The San Ramón Fault is an active west-vergent thrust fault system located along the eastern border of the city of Santiago, at the foot of the main Andes Cordillera. This is a kilometric crustal-scale structure recently recognized that represents a potential source for geological hazards. In this work, we provide new seismological evidences and strong ground-motion modeling from hypothetic kinematic rupture scenarios, to improve seismic hazard assessment in the Metropolitan area of Central Chile. Firstly, we focused on the study of crustal seismicity that we relate to brittle deformation associated with different seismogenic fringes in the main Andes in front of Santiago. We used a classical hypocentral location technique with an improved 1D crustal velocity model, to relocate crustal seismicity recorded between 2000 and 2011 by the National Seismological Service, University of Chile. This analysis includes waveform modeling of seismic events from local broadband stations deployed in the main Andean range, such as San José de Maipo, El Yeso, Las Melosas and Farellones. We selected events located near the stations, whose hypocenters were localized under the recording sites, with angles of incidence at the receiver\5°and S-P travel times\2 s. Our results evidence that seismic activity clustered around 10 km depth under San José de Maipo and Farellones stations. Because of their identical waveforms, such events are interpreted like repeating earthquakes or multiplets and therefore providing first evidence for seismic tectonic activity consistent with the 123Nat Hazards (2014) 71:243-274 DOI 10.1007 crustal-scale structural model proposed for the San Ramón Fault system in the area (Armijo et al. in Tectonics 29(2):TC2007, 2010). We also analyzed the ground-motion variability generated by an M w 6.9 earthquake rupture scenario by using a kinematic fractal k -2 composite source model. The main goal was to model broadband strong ground motion in the near-fault region and to analyze the variability of ground-motion parameters computed at various receivers. Several kinematic rupture scenarios were computed by changing physical source parameters. The study focused on statistical analysis of horizontal peak ground acceleration (PGAH) and ground velocity (PGVH). We compared the numerically predicted ground-motion parameters with empirical ground-motion predictive relationships from Kanno et al. (Bull Seismol Soc Am 96:879-897, 2006). In general, the synthetic PGAH and PGVH are in good agreement with the ones empirically predicted at various source distances. However, the mean PGAH at intermediate and large distances attenuates faster than the empirical mean curve. The largest mean values for both, PGAH and PGVH, were observed near the SW corner within the area of the fault plane projected to the surface, which coincides rather well with published hanging-wall effects suggesting that ground motions are amplified there.

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Section: Introductionmentioning

confidence: 99%

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

et al. 2013

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“…A total of 22 large earthquakes with M ≥ 7, including the Shillong earthquake of Mw 8.0 (1897) and Assam earthquake of Mw 8.6 (1950), have occurred in the north-east region between 1897 and 1962 (Kayal et al, 1993;Islam et al, 2011;Tandon & Gupta, 2020). Other notable events are the 1869 Cachar earthquake (Mw 7.7), the 1918 Srimangal earthquake (Mw 7.5) and the 1930 Dhubri (Mw 7.1) (see Raghu Kanth & Dash, 2010). The high seismicity of this region can also be understood from the fact that it has experienced 29 events (magnitude ≥ 6.0mb) for the period 1964-2020.…”

Section: Seismicity Of the Region And Division Of Seismic Zonesmentioning

confidence: 99%

Frequency magnitude distribution and spatial correlation dimension of earthquakes in north-east Himalaya and adjacent regions

Tiwari

Paudyal

2022

Geologos

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The north-east sector of the Himalaya is one of the most active tectonic belts, with complex geological and tectonic features. The b-value and spatial correlation dimension (Dc) of earthquake distribution in the north-east Himalaya and its adjacent regions (20–32°N and 88–98°E) are estimated in the present study. Based on seismicity and faulting pattern, the region is divided into five active regions, namely the (i) South-Tibet, (ii) Eastern-Syntaxis, (iii) Himalayan-Frontal Arc, (iv) Arakan-Yoma belt and (v) Shillong-Plateau. A homogeneous catalogue of 1,416 earthquakes (mb ≥ 4.5) has been prepared from a revised catalogue of the ISC (International Seismological Centre). The b-value has been appraised by the maximum likelihood estimation method, while Dc values have been calculated by the correlation integral method; b-values of 1.08 ± 0.09, 1.13 ± 0.05, 0.92 ± 0.05, 1.00 ± 0.03 and 0.98 ± 0.08 have been computed for the South-Tibet, Eastern-Syntaxis, Himalayan-Frontal Arc, Arakan-Yoma belt and Shillong-Plateau region, respectively. The Dc values computed for the respective regions are 1.36 ± 0.02, 1.74 ± 0.04, 1.57 ± 0.01, 1.8 ± 0.01, and 1.83 ± 0.02. These values are > 1.5, except for the South-Tibet (1.36 ± 0.02). The b-values around the global average value (1.0) reflect the stress level and seismic activity of the regions, while high Dc values refer to the heterogeneity of the seismogenic sources.

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“…The theory and application of seismological models for estimating ground motion has been discussed in detail by Boore (1983Boore ( , 2009) and Motazedian and Atkinson (2005). The application of seismological model for estimating ground motion in northeastern India has been discussed in detail by Raghukanth and Somala (2009) and Raghukanth and Dash (2009). A brief description of the method starting with the frequency domain representation of the ground acceleration will bring out the advantages of this approach.…”

Section: Seismotectonic Setting and Source Of Sikkim Earthquakementioning

confidence: 99%

Estimation of ground motion during the 18th September 2011 Sikkim Earthquake

Raghukanth

Kumari

Kavitha

2012

Geomatics, Natural Hazards and Risk

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This article simulates the ground motion during the devastating 18th September 2011 Sikkim earthquake by analytical approaches. Surface level peak ground acceleration (PGA) values at several stations in the epicentral region have been estimated by the finite fault seismological model. A PGA contour map in the epicentral region is provided. It is found that very near to the epicentre, PGA would have reached more than 0.3g. The SPECFEM3D_GLOBE package which models the complete three-dimensional wave velocity structure and topography is used to simulate the displacement time histories on a global scale. A contour map of peak ground displacement (PGD) and permanent ground residual displacements (PGRD) in the near source region is provided. The estimated ground motions are validated with that obtained from damage values.

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Deterministic seismic scenarios for North East India

Cited by 31 publications

References 35 publications

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

Frequency magnitude distribution and spatial correlation dimension of earthquakes in north-east Himalaya and adjacent regions

Estimation of ground motion during the 18th September 2011 Sikkim Earthquake

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