Spatiotemporal Variation of Ambient Noise Levels and Cross-Correlations observed in Gujarat, India
Abstract
To understand the correlation between the environmental turbulence imposed by the monsoon activity and the seismic microseisms, we have analyzed the seismic ambient noise levels at 39 broadband seismic stations in Gujarat, India. The results suggest a strong temporal variation of the power of secondary microseism (2-10 s), which may be an indication of the intensities of monsoons at least in Gujarat. The ambient noise CCF also presents a similar pattern, in which the energy in the period band of secondary microseism is much stronger during the monsoon season. A precursory signal of the CCFs around the zero lag-time is observed, but it disappears during the monsoon season. Possible mechanisms responsible for this observation remain unclear. In addition, 589 CCFs among these 39 stations have been retrieved as the empirical green's functions. We applied a multi-scale inversion scheme to derive 2-D tomographic images for both group and phase velocities at various periods. The result may reflect the heterogeneity of the geological regions in Gujarat, India.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.S41A2770L
- Keywords:
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- 3260 Inverse theory;
- MATHEMATICAL GEOPHYSICSDE: 3275 Uncertainty quantification;
- MATHEMATICAL GEOPHYSICSDE: 7270 Tomography;
- SEISMOLOGYDE: 7290 Computational seismology;
- SEISMOLOGY