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| Geothermic activity and seismotectonics in the altitude of the Tibetan plateau |
| Jiren Xu, Zhixin Zhao |
| Institute of Geology，Chinese Academy of Geological Sciences, Beijing 100037, China |
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Abstract In the present analysis on the relationships among the depth of lithosphere brittle fracture, seismotectonics and geothermal anomalous active in Tibetan plateau were investigated using the seismic dada from ISC and Chinese seismic net and geothermal data. The results suggest that the region of anomalously geothermal activity almost coincides with that of the normal faulting type earthquake. The geothermal anomaly activity region coincides spatially with that of the events deeper than 60 km as well as. The normal faulting earthquakes may be mainly tectonic activity regimes until 110 km deep in the thermal anomaly region. The strike directions of events are likely the N-S direction, coinciding with the strike of the thermal anomaly active belts. The earthquakes align along the normal faults and faulted-depression zone with the N-S direction. The thermal anomaly activity also distributes along the faulted-depression zone. Many events deeper than 60 km exist in the anomalously geothermal activity region in the plateau. Events extend to bottom of the lithosphere of 110 km from the surface, like columnar seismic crowd. The lithosphere extends along the E-W direction due to the E-W extensional stress in the central and southern Tibetan plateau, altitude of the plateau. The tensional stress in the E-W results in the lithosphere fractures and the normal faults striking N-S direction, grabens and faulted-depression zones. Thermal material from the asthenosphere wells upward to the surface along deep seismic fractures and faults through the thick crust. The anomalously thermal activities are attributable to the upwelling thermal material from the mantle in the altitude of Tibetan plateau.
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Received: 12 June 2009
Published: 10 December 2009
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| Fund:National Natural Science Foundation of China (No.40674026), Commonweal Special Science Foundation of China (No. 200811037) and Geological Survey Foundation of Ministry of Land and Resource, China (No.1212010916083) |
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Corresponding Authors:
Jiren Xu
E-mail: xujiren1125@yahoo.com.cn
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