Crustal Structure of the Himalayan Foothills using Noise Correlation Tomography
Abstract
The Himalayan arc comprises a unique continent-continent collision zone governed by shallow angle thrust faulting environment that has experienced 4 great earthquakes of magnitude greater than 8.0 in the last century, posing a serious seismic hazard to millions of people. However, this region continues to be one of the least understood tectonic belts of the world both in terms of crustal structure and related deformation, with barely any clue to the forthcoming great earthquake. Major international efforts have gone into comprehending the structure and evolution of the adjoining Tibetan plateau in the north, with the help of active and passive seismic experiments like PASSCAL, GEDEPTH, INDEPTH, HIMNT and NAMCHABARWA. However, the continuation of the inferred tectonic models further south in the Himalayan foothills and the Indo-Gangetic plains has remained an enigma. In the present study ambient noise recorded by Indian networks of seismic broadband stations in the Indo-Gangetic plains near central Himalaya and in the Sikkim Himalaya towards east, has been analyzed to decipher the crustal structure. The derivative of the cross-correlation of ambient noise between any two stations represents the equivalent Green’s function that can be modeled in terms of the seismic structure. The results provide new images of the shear velocity structure which in conjunction with the results from Tibet and Nepal Himalaya provide new understanding of the underlying the collision processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.S33B1771R
- Keywords:
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- 0545 COMPUTATIONAL GEOPHYSICS / Modeling;
- 3270 MATHEMATICAL GEOPHYSICS / Time series analysis;
- 7205 SEISMOLOGY / Continental crust;
- 7270 SEISMOLOGY / Tomography