TITLE:
Deep Geoelectric Structure and Its Relation to Seismotectonics of the Saurashtra Region, Western India
AUTHORS:
D. N. Murthy, K. Veeraswamy, T. Harinarayana
KEYWORDS:
Magnetotelluric, Seismotectonics, Geoelectric Structure, Earthquakes, Electrical Conductivity
JOURNAL NAME:
Open Journal of Earthquake Research,
Vol.9 No.2,
March
27,
2020
ABSTRACT: The Saurashtra Peninsula and its adjoining regions covered by Deccan Traps (DT) are one of the important parts of the Indian continental lithosphere with interesting geophysical anomalies, tectono-thermal evolution since the Mesozoic times. Knowledge on the deep structure beneath these formations is important for understanding the seismo-tectonics of the region. This region has gained importance after the occurrence of a major earthquake (7.9 Mw) north of Saurashtra, namely Bhuj earthquake during 2001. It is also observed that Saurashtra region has experienced several earthquake swarms limited to small regions. Accordingly, it is important to investigate the deep structure of the Saurashtra region from seismotectonics point of view. In our study, magnetotelluric results of the deep crustal structure along five NS oriented traverses are presented. The five traverses are—Halvad-Rohisa (HR), Sapar-Iswaria (SI), Mota Dahinsara-Bamagadh (MB), Jodiya-Jamkhandorna (JJ) and VavBeraja-Devda (VD). The total length of these 5 traverses is about 670 km. The derived deep geoelectric structure is also compared and correlated with gravity data to get more confidence on the derived results. The 2-D geoelectric section has delineated anomalous high conductivity structure at places extending from 20 km to about 40 km. From the spatial correlation, anomalous high conductive structure derived from MT data with intense localized seismic activity is an interesting observation. In the present study, the results of magnetotelluric studies along with other geophysical results are presented.