High-Resolution Attenuation Model for Gujarat: State of Western India
Abstract
In India, Gujarat belongs to the highest seismicity zone other than Himalayan belts. It has suffered from great economic and social loss due to many large magnitude earthquakes in the past. Thus the area needs a special attention from the seismic hazard point of view. It is the state of intraplate earthquakes similar to New Madrid Seismic zone in the United States. In the present study we have prepared a Lg attenuation tomographic model for Gujarat. The study also employs the other complementary information to get a detailed understanding into the mechanisms of attenuation. It will be useful in seismic hazard risk study and in estimating the source parameters of earthquakes. The amplitude of Lg wave is sensitive to different tectonic structures like faults, mountains and ocean basins. It travels predominantly through the continental crust but does not travel across ocean basins. Fifteen earthquakes of Mb >5 recorded at 40 stations operated in the region are chosen for the initial LgQ measurement using the standard two-station method. Finally, 5 events with 70 high-quality inter-station paths are selected from 117 possible pairs that are (1) aligned approximately with the source and (2) separated enough to permit the use of the standard two-station method for LgQ estimation. By using these values of Q0 (1 Hz LgQ) as input, an inversion is performed to have a Lg Q model for the region. A drastic spatial variation in Q0 has been noticed across our study region. Kutch, Jamnagar area are characterized by lowest Q0 values (<50) and south-east region of Saurashtra peninsula shows high Q0 (>300). These variations could be correlated with thermal effects, petrophysical properties and heterogeneity present in the crust.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.S53A2834J
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7215 Earthquake source observations;
- SEISMOLOGYDE: 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGY