Table of Contents
Journal of Earthquakes
Volume 2015, Article ID 572619, 8 pages
Research Article

Mapping Sediment Thickness in Shillong City of Northeast India through Empirical Relationship

1Department of Physics, Tezpur University, Tezpur, Assam 784028, India
2Geoscience Division, CSIR-North East Institute of Science and Technology, Jorhat, Assam 785006, India
3Diphu Government College, Karbi Anglong, Assam 782462, India

Received 2 July 2014; Revised 11 December 2014; Accepted 21 December 2014

Academic Editor: Jose Restrepo

Copyright © 2015 Rajib Biswas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Modified form of Nakamura method, ratio, is used to assess the site response through estimation of fundamental resonant frequency at 70 sites using three component digital seismographs in Shillong city, capital of Meghalaya in northeast India. With available borehole information, an attempt is made to develop an empirical relationship between sediment thickness and resonant frequency estimated from ratio technique. Simultaneously, shear wave velocities are computed entailing resonant frequency and sediment thickness for these boreholes. We also endeavored building another empirical relation between sediment thickness and . With the help of this, the probable values for other sites were also evaluated. It is observed that shear wave velocities range from 200 to 550 m/s while sediment thickness ranges from 10 to 80 m, implicating the heterogeneity prevailing in the soil layers of the Shillong city.