Comprehensive Probabilistic Seismic Hazard Analysis of the Andaman-Nicobar Regions

Abstract

An updated catalog of earthquakes has been prepared for the AndamanNicobar and adjoining regions. The catalog was homogenized to a unified magnitude scale, and declustering of the catalog was performed to remove aftershocks and foreshocks. Eleven regional source zones were identified in the study area to account for local variability in seismicity characteristics. The seismicity parameters were estimated for each of these source zones, and the seismic hazard evaluation of the Andaman-Nicobar region has been performed using different source models and attenuation relations. Probabilistic seismic hazard analysis has been performed with currently available data and their best possible scientific interpretation using an appropriate instrument such as the logic tree to explicitly account for epistemic uncertainty by considering alternative models (source models, maximum magnitude, and attenuation relationships). The hazard maps for different periods have been produced for horizontal ground motion on the bedrock level.

Probabilistic seismic hazard assessment of Nepal using multiple seismic source models

“…The spatial variation pattern of the hazard value shows good agreement with the maps of Zhang PZ et al (1999), Ram and Wang GX (2013), and Rahman et al (2018). In addition, the resulting hazard values for the Nepal area are comparable with results for the adjacent regions in India (e.g., Kolathayar and Sitharam, 2012;Nath and Thingbaijam, 2012) and Tibet (Rahman et al, 2018). The rock-site PGA value around the epicenter of the 2015 Gorkha earthquake shown in previous studies (e.g., Chaulagain et al, 2015;Ram and Wang GX, 2013;Zhang PZ et al, 1999) is below 0.4g.…”

“…The weight assessment and thereby the ranking of different GMPEs are not carried out because of scarcity of strong motion records in the Himalayan‐Tibetan region. Due to insufficient observed data, many seismic hazard studies for Asian countries (e.g., Chaulagain et al, ; Kolathayar and Sitharam, ; Nath and Thingbaijam, ; Ornthammarath et al, ) used equal weight for all models. In this study, therefore, for each of these four models, equal probabilistic weights (1/4) are assigned.…”

A procedure to select ground-motion time histories for deterministic seismic hazard analysis from the Next Generation Attenuation (NGA) database

“…Over the past decades, numerous seismic hazard studies have been conducted with the two methods (e.g., Joshi et al, 2007;Kolathayar and Sitharam, 2012;Moratto et al, 2007;Sitharam and Vipin, 2011;Stirling et al, 2011). The two methods have also been prescribed in various technical references.…”

A Procedure to Select Earthquake Time Histories for Deterministic Seismic Hazard Analysis: Case Studies of Major Cities in Taiwan

“…PSHA and DSHA are the two representative approaches in assessing earthquake hazards. Over the past decades, numerous seismic hazard studies have been conducted with the two methods (e.g., Joshi et al, 2007;Kolathayar and Sitharam, 2012;Moratto et al, 2007;Sitharam and Vipin, 2011;Stirling et al, 2011 It is worth noting that extensive discussions over the pros and cons of the two methods have been reported in the literature (e.g., Bommer, 2003;Castanos and Lomnitz, 2002;Krinitzsky, 2003;Klugel, 2008). In general, DSHA is a simple approach that earthquake scenarios are considered logically understandably, but the uncertainties in DSHA may not be well quantified.…”