SEISMIC HAZARD ASSESSMENT OF GARHWAL REGION, HIMALAYA

¹ Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

²Indian Institute of Technology Hyderabad, Hyderabad, India

* e-mail: ertel@ifz.ru

Abstract. Garhwal region is one of the most seismically active areas in India. This territory, in the past, had destructive earthquakes more than once. The present seismic activity of Garhwal is relatively higher. This area is characterized by a high population density. Protecting the population and reducing material damage from possible strong seismic events is an urgent task when choosing ways to develop the region under consideration. Its solution requires, first of all, the use in the construction of various anti-seismic designs, the choice of which is determined by the characteristics of seismic treatments (impacts). The purpose of this article is to assess the seismic hazard and seismic treatments for the settlements in the Garhwal region. New data from the previous stages of the study of the Western Himalayas region under consideration are used to solve this problem: 1) the results of geologic-geophysical and structural geology studies made it possible to identify the main earthquake generating structures and their characteristics; 2) the strong ground motions data from the epicenter areas of Dharamsala (26.04.1986, M_w = 5.5), Uttarkashi (20.10.1991, M_w = 6.8) and Chamoli (28.03.1999, M_w = 6.5) earthquakes were analyzed; the rules of peak ground accelerations attenuation were investigated in the Garhwal region. In this article the maximum possible magnitude, source depths and source mechanisms of the earthquake are assessed. The regional model of seismic sources zones (SSZ) is proposed. Using the results of seismic and seismotectonic studies, the parameters of strong ground motions during the maximum possible earthquakes are estimated – peak ground accelerations, spectra and duration of oscillations, as well as the seismic effect value in the seismic intensity scale points for some cities and towns of the Garhwal region.

Keywords: Western Himalaya, Garhwal, seismotectonics, fault, magnitude, source mechanism, distance, ground conditions, strong ground motions, seismic intensity, seismic source zone, peak ground acceleration, seismic hazard, earthquake.

About the authors

ROGOZHIN Eugeniy Aleksandrovich – Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. Russia, 123242, Moscow, Bolshaya Gruzinskaya st., 10-1. E-mail: eurog@ifz.ru

SOMALA Surendra Nadh – Indian Institute of Technology Hyderabad, Department of Civil Engineering. India, Telangana, Sangareddy, Kandy, 502285, Hyderabad, NH-65, IITH main road, IIT Hyderabad. E-mail: surendra@iith.ac.in

ERTELEVA Olga Olegovna – Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. Russia, 123242, Moscow, Bolshaya Gruzinskaya st., 10-1. E-mail: ertel@ifz.ru

APTIKAEV Felix Fuadovich – Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. Russia, 123242, Moscow, Bolshaya Gruzinskaya st., 10-1. E-mail: felix@ifz.ru

CHANDA Sarit – Indian Institute of Technology Hyderabad, Department of Civil Engineering. India,
Telangana, Sangareddy, Kandy, 502285, Hyderabad, NH-65, IITH main road, IIT Hyderabad. E-mail: ce16resch11006@iith.ac.in

Cite this article as: Rogozhin E.A., Somala S.N., Erteleva O.O., Aptikaev F.F., Chanda S. Seismic hazard assessment of Garhwal region, Himalaya, Geofizicheskie Protsessy i Biosfera (Geophysical Processes and Biosphere), 2020, vol. 19, no. 4, pp. 5–15 (in Russian). https://doi.org/10.21455/gpb2020.4-1

English version: Izvestiya, Atmospheric and Oceanic Physics, 2020, vol. 56, iss. 11. ISSN: 0001-4338 (Print), 1555-628X (Online). https://link.springer.com/journal/volumesAndIssues/11485