Lateral Variation in Crustal Structure of the Northern Tibetan Plateau Inferred from Teleseismic Receiver Functions
- Creators
- Zhu, Lupei
- Owens, Thomas J.
- Randall, George E.
Abstract
We investigate lateral variations in crustal structure across the northern boundary of the Tibetan Plateau using the receiver functions at three broadband stations deployed during the 1991-1992 Tibet PASSCAL experiment. The first 5 sec of the receiver functions vary systematically with backazimuth: the radial receiver functions are symmetric across the N-S axis while the tangential receiver functions are antisymmetric across this axis. This symmetry can be modeled by E-W striking dipping interfaces in the upper-middle crust. The strike direction is consistent with the E-W trend of surface geology. Modeling a P-to-S converted phase in the receiver functions at each station suggests that there is a mid-crustal low-velocity layer with its upper boundary dipping 20° to 30° to the south. In addition, a shallow northward-dipping interface is responsible for the "double-peaked" direct P arrivals in the radial receiver functions and large tangential motions at one of the stations. The low-velocity layer, together with other geological and seismological observations, suggests that there is a hot, possibly partial melt zone in the middle crust of northern Tibet. Alternately, dipping velocity interfaces might be associated with some buried thrust faults in the upper crust that accommodated crust shortening during the plateau formation.
Additional Information
© 1995, by the Seismological Society of America. Manuscript received 20 August 1994. We thank C. J. Ammon for his careful review of the manuscript. This work was supported at University of South Carolina under NSF Grants EAR-9196115. It has also been supported at Caltech by the Department of Defense as monitored by the Air Force Office of Scientific Research under Contract F49620-92-J-0470. Contribution No. 5540, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.Attached Files
Published - 1531.full.pdf
Files
Name | Size | Download all |
---|---|---|
md5:cd98ec5623eacff715928eac857e43a0
|
1.5 MB | Preview Download |
Additional details
- Eprint ID
- 48139
- Resolver ID
- CaltechAUTHORS:20140806-152650992
- EAR-9196115
- NSF
- F49620-92-J-0470
- Air Force Office of Scientific Research (AFOSR)
- Created
-
2014-08-06Created from EPrint's datestamp field
- Updated
-
2019-10-03Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological and Planetary Sciences
- Other Numbering System Identifier
- 5540