Establishing Empirical Correlation between Sediment Thickness and Resonant Frequency using HVSR for the Indo-Gangetic Plain

Abstract

In this study, microtremor survey was carried out at 31 locations of Indo-Gangetic Plains (IGP) using a pair of portable three-component short-period seismometers (Guralp CMG-6T-1) and Kelunji Echo Pro digital data acquisition system. The acquired raw data was processed to obtain the average H/V ratio of the ambient vibration spectrum. The frequency corresponding to the first peak of the average H/V spectrum was taken as resonant frequency of that particular site. A comparison was made between the resonant frequencies obtained from peak of the H/V spectrum with those obtained using the source-receiver function from previously published work. The results were in good agreement with each other. An empirical equation has been established for the IGP by relating resonance frequency with sediment thickness, using available data from nearby boreholes drilled up to bedrock. The empirical equation was compared with other equations available for deep soil sites, i.e. sites with soil thickness more than 750 m. Further, a combined equation was developed for the digitized data taken from previously published works of deep soil sites. Finally, it has been found that the regionspecific equation gives better estimate of sediment thickness than the other empirical equations; but in absence of such a region-specific equation, the proposed combined equation can be used for a quick preliminary assessment of sediment thickness of a deep soil region.

Bedrock Depth Calculation of Çanakkale (Turkey) Basin Using Rayleigh Ellipticity and Microgravity Survey

“…On the other hand, it is imperative to generate the bedrock depth information to obtain a complete ground structure model in basin-type structures and to model information such as possible soil amplification and acceleration distribution. For this purpose, many studies have been carried out to obtain bedrock depth with experimental relations from inversion based on ambient vibration measurements (Delgado et al, 2000a;Hinzen et al, 2004;García-Jerez et al, 2006;D'Amico et al, 2008;Birgören et al, 2009;Özalaybey et al, 2011;Harutoonian et al, 2013;Fairchild et al, 2013;Del Monaco et al, 2013;Mendecki et al, 2014;Kuo et al, 2016;Sant et al, 2017;Molnar et al, 2018;Liang et al, 2018;Moon et al, 2019;Thabet, 2019;Anbazhagan et al, 2019;Rupar and Gosar, 2020;Büyüksaraç et al, 2021;Maghami et al, 2021).…”

An Empirical Correlation between the Residual Gravity Anomaly and the H/V Predominant Period in Urban Areas and Its Dependence on Geology in Andean Forearc Basins

“…However, a correlation between both methods, if it exists, has not been thoroughly studied, and thus very little information is available on whether one method could be an estimator of the other. A large part of available studies deals with the relationship between H/V frequency and depth to the basement derived from other techniques, such as boreholes or other seismic data [26][27][28][29][30][31][32]. Some other authors incorporate gravity information in their studies, to estimate the sediment thickness, e.g., [21,23,24], but these studies are not orientated to determining a correlation between both techniques, but rather they use the information to reach other objectives.…”