Probabilistic seismic hazard analysis using logic tree approach – Patna District (India)

Abstract

Abstract. PGA and SA distribution for Patna district is presented considering both classical and zoneless approach through logic tree frame work to capture the epistemic uncertainty. Seismicity parameters are calculated by considering completed and mixed earthquake data. Maximum magnitude was calculated using three methods namely incremental method, Kijko method and regional rupture characteristics approach. Best suitable GMPE was selected by carrying out efficacy test using log likelihood. Uniform hazard response spectra have been compared with Indian standard BIS 1893. PGA varies from 0.38 g to 0.30 g from southern to northern periphery considering 2 % probability of exceedence in 50 years.

An integrated assessment of seismic hazard exposure and its societal impact in Seven Sister States of North Eastern Region of India for sustainable disaster mitigation planning

“…In this study, an open-source software ZMAP (v7.0) by Wiemer (2001) is utilized to eliminate the dependent events by following the methodology proposed by Gardner and Knopoff (1974) which follows a Poisson distribution (Stiphout et al 2012). A similar procedure has been followed by Sitharam and Sil (2014), and Anbazhagan et al 2019.…”

“…The objective of the present study is to develop the updated seismic hazard map of the Seven Sister States of northeast India using PSHA based on the updated earthquake catalogue and conduct social vulnerability assessment and exposure to seismic hazard. A circle of radius 500 km (around 26.16°N and 93.28°E) covering the entire NER is constructed for the development of the seismotectonic model, and the region is segmented into 0.2° x 0.2° grids (Anbazhagan et al 2019). Following the PSHA approach, the seismic hazard is assessed at the center of each grid.…”

Some comments and criticisms for an application of logic tree approach (Probabilistic seismic hazard analysis using logic tree approach-Patna District, India)

“…Printer-friendly version Discussion paper ing estimations, the branches with slight differences are strongly recommended to be avoided (Bommer et al, 2005). Hence, readers of the article should be informed whether the authors avoided from similar nodes in the logic tree branches.…”

“…3) Past works (Sabetta et al 2005;Scherbaum and Kühn, 2011) indicate that selection of attenuation models (i.e., ground motion prediction equations) is much important for seismic hazard analysis using the logic tree approach. Moreover, their selection for the seismic hazard assessment has a greater impact than expert's judgments for the weightings of the logic tree branches.…”

“…2) One of the power utilities of the logic tree comes from its relatively less effort compared to the conventional seismic hazard methodologies. It is important to note that using the logic tree with the judged weighting factor requires a calculation effort that dramatically increases with increased branches (Bommer et al, 2005;Sabetta et al, 2005). Thus, in order for preventing the troubles from the increased branches dur-…”