Publication Date:
2011-08-01
Description:
Using data from regional earthquakes recorded by the Hi-CLIMB array in Tibet, we model P-wave arrival times to constrain the velocity structure in the crust and the upper mantle in central and western Tibet. Of more than 30 high-quality, regional seismic profiles that have been assembled, we have selected 10 that show excellent crustal and Pn arrivals for further analysis. Travel times from four events along the Hi-CLIMB array provide details on crustal velocities, and six events at regional distances to the array provide further constraints on Moho structure and upper-mantle-lid velocities. We use three-dimensional ray tracing to model the travel times, and the results indicate that the Moho beneath the Lhasa terrane of southern Tibet is over 73 km deep, with a Pn speed of about 8.2 km/s. The Qiangtang terrane north of the Bangong-Nujiang suture (BNS) shows a thinner crust, by up to 10 km, and a lower Pn speed of 7.8-7.9 km/s. Travel times from events to the west and east of the array indicate that both Moho structure and mantle-lid velocities in the region are three-dimensional in nature but approximately follow the trend of the BNS. Although only a limited number of events were used for the travel-time modeling, the results are consistent with earlier results from teleseismic imaging using the Hi-CLIMB array.
Print ISSN:
0037-1106
Electronic ISSN:
1943-3573
Topics:
Geosciences
,
Physics
Permalink
