V_S30 mapping and site characterization in the seismically active intraplate region of Western India: implications for risk mitigation

Abstract

A B S T R A C TWe carried out shallow subsurface investigations at 600 sites covering all types of geological units in the Northwestern Deccan Volcanic Province of India, using the multichannel analysis of surface waves and suspension PS-logging methods. The results reveal that V S30 values are in the range of 760-1500 m/s for granites and Deccan traps, thus enabling their classification as B-class, as per the National Earthquake Hazard Reduction Program recommendations. The Tertiary, Cretaceous, Jurassic and Paleoproterozoic sediments show V S30 values between 360 and 760 m/s, and hence, are assigned C-class. Further, the Quaternary soils are categorized as D-class, since they show V S30 in the range of 180-360 m/s. Also, the Holocene tidal flat and Rann sediments are classified as E-class, since the V S30 values are less than 180 m/s. The observed site response reveals that the D-and E-type soils have significantly higher seismic amplification than that in the B-and C-category soils. We noticed that the buildings on D-and E-classes soils experienced higher damage than those on the B-and C-classes, during the past large earthquakes in the Northwestern Deccan Volcanic Province. Our study suggests that V S30 is a good proxy for soil classifications in the Northwestern Deccan Volcanic Province. We validated our results using available geological, geophysical and geotechnical data. For the first time, a regional site characterization map for the Northwestern Deccan Volcanic Province of India is prepared based on geology and V S30 .

Subsoil classification and geotechnical zonation for Guadalajara City, México: Vs30, soil fundamental periods, 3D structure and profiles

“…; Sairam et al . ). It is used for building codes, earthquake resistant design, shake maps or, like in this work, to define a seismic zonation within an urban area.…”

“…Although these techniques are available and have been used since the late 1950s, better instrumentation and computational resources developed in the last four decades have resulted in a dramatic increase in the quantity and quality of array recording (e.g. Flores Estrella and Aguirre Gonzalez 2003;Scherbaum, Hinzen and Ohrnberger 2003;Bonnefoy-Claudet et al 2006;Kanli et al 2006;Mohamed et al 2013;Hollender et al 2018;Vicêncio, Teves-Costa and Sá Caetano 2018;Mahajan and Kumar 2018;Pergalani et al 2020;Sairam et al 2019).…”

“…Presently, V S30 is a well-accepted and robust parameter used to characterize local site response (e.g. Kanli et al 2006;Rošer and Gosar 2010;Hollender et al 2018;Sairam et al 2019). It is used for building codes, earthquake resistant design, shake maps or, like in this work, to define a seismic zonation within an urban area.…”

Seismic site classification of Nakhon Nayok City, central Thailand, using the MASW technique

“…It was found that the derived Vs. profiles were compared between these two different approaches, which were found to be in good agreement. Sairam et al (2019) conducted the MASW survey for 600 sites in the Northwestern Deccan Volcanic Province of India. Their study suggested that Vs. derived from the MASW method is a good proxy for soil classifications.…”

Vs30 Structure of Almeria City (SE Spain) Using SPAC and MASW Methods and Proxy Correlations

“…Consequently, these crucial V s30 -based maps would provide the potential variations in earthquake shaking due to local site effects based on subsurface ground conditions, such as degree of stiffness and the thickness of the geological materials. These maps are of vital importance in ground motion modeling and probabilistic seismic hazard assessment [10]. Therefore, V s30 is a primary indicator of both the stiffness of near-surface formations and their site effects, since it provides closed-form expressions relating short-and mid-period amplification factors with depth [2,[10][11][12].…”