Seismic Evidence for Small-scale Shear Velocity Variance of D" Layer beneath Northern Indian Plate
Abstract
We study the structure of D" beneath northern India using differential travel time residuals of S and ScS phases recorded in waveforms from the Chinese Digital Seismic Network generated by 6 shallow earthquakes from 2009 to 2017 with magnitude larger than and/or equal to Mw 5.6 in northern Indian Rise and Gulf of Aden. We model the data using specfem3d_globe synthetics based on CRUST1.0 for the crust, S40RTS for the mantle, and AK135 for the lowermost 300 km of the mantle. High-velocity anomalies in D" are dominant within the study area, particularly beneath the central part of the northern India. We map two low-velocity zones beneath the westernmost and eastern portions of the India. Our analysis indicates that the shear velocity varies by about 6% over distances shorter than 300 km at the CMB due to thermochemical structure in D".
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMDI53A0049L
- Keywords:
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- 1038 Mantle processes;
- GEOCHEMISTRYDE: 3924 High-pressure behavior;
- MINERAL PHYSICSDE: 7208 Mantle;
- SEISMOLOGYDE: 8125 Evolution of the Earth;
- TECTONOPHYSICS