Use of Remotesensing and Seismotectonic Parameters to Identify
Seismgenic Sources of Tamil Nadu
Abstract
The present study aims at to understand the geologically controlled Lineaments and analysis the regional seismicity of Tamil Nadu.A remote sensing and GIS approach with limitedground truth verification is used for the present study to meet the objectives of the study. From the satellite imagery 257 lineaments have been delineated for Tamil Nadu based on visual interpretation. The 59 seismically active lineaments/ faults have been identified based on their spatial association with 103 epicenters of earthquakes and their magnitudes are in the range of < 3 to 5.6. The length of those lineaments varies from 10 km to 315km. The faults have prominent trend in the directions N30 50 degrees E, N10 40 degrees W, and EW. The calculated stress drop for the 59 seismically active lineaments is low in the range of <1bar to 2.56 barsand it indicates that low stress drop thereby revealing that tectonic adjustment is undergoing in the upper crust. Generally there is a positive correlation between longer length of lineaments and higher association of number of epicenter of earthquakes.The distribution of lineaments, the epicenter of earthquakes and intrusive complexes confirm that the northern part of Tamil Nadu has higher seismic activity than the southern part 0of Tamil Nadu.The absence of an epicenter in the areas of granite intrusive and presence of epicenters in the areas of ultrabasics indicate that the earthquakes are associated with deep seated fractures.The result of the study will play a key role in Seismic Hazard Assessment for the State.
Key Words: Remotesensing, lineaments, faults, seismicity and Earthquake.
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