Intermediate depth earthquakes beneath the India-Tibet Collision Zone
Article first published online: 7 DEC 2012
Copyright 1996 by the American Geophysical Union.
Geophysical Research Letters
Volume 23, Issue 5, pages 435–438, 1 March 1996
How to Cite
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 19 DEC 1995
- Manuscript Received: 5 JUN 1995
We report on three intermediate depth earthquakes in the India-Tibet collision zone, two under the Himalayan Thrust Belt (HTB) and one beneath the Indus Zangbo suture. The mb magnitudes of these three events are from 4.3 to 4.9, and are too small to be well located by conventional means. However, from modeling their broadband waveforms recorded at near-regional distances on a temporary PASSCAL array, we can confidently confine the sources to be below the crust, between 70 and 80 km deep. The existence of these intermediate depth earthquakes in this area suggests relatively low temperatures in the mantle lithosphere. The two events under the HTB display strike-slip mechanisms with some normal faulting component; this is quite different from the shallow thrust events typical of the same area. The principal P and T axes of all 3 fault plane solutions show roughly NS compression and EW extension, consistent with a regional stress field produced by the indenting of the India continent.