| 新疆塔里木—西昆仑宽频地震观测实验研究 |
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| 关键词:broadband seismic deployment Tibet Tarim Kunlun Mountains Collision and deformation |
| 基金项目:国土资源部前沿科技计划项目(编号:9501204)，国家自然科学基金委员会项目(编号:F4973230)，国家新疆305专项(编号:96-915-07-03)，国家重点基础研究发展规划项目(编号:G1998040800) |
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| 摘要: |
| Broadband Seismic Obsevational Experiments from Tarim Basin to Kulun Mountains |
| A broadband seismic deployment in 1998～1999 in southwestern Tarim provided data for imaging the crust and upper mantle across the contact zone between the Tarim block and the Tibetan plateau. The Tarim basin is located to the north of Tibet and seems to be a seismic block in Northwest China. It is surrounded by two large mountain systems, namely the Tianshan Mountains and the Kunlun Mountains on the north and the south respectively, where high seismicity is observed. Although its flat platform and seismic characteristics are recognized, how the Tarim block deforms internally and interacts with its neighboring areas remain unclear. In mid I997, the Institute of Geology, Chinese Academy of Geological Sciences and the Institute of Earth Sciences, Academia Sinica, initiated a corporate effort to study the seismotectonics of the Tarim basin. In particular, the project was focused on the transition between Tarim and Tibet, namely, the Kulunshan foreland. The full scale experiment began in mid 1998 with the emphasis placed on southern Tarim. A total of 12 broadband stations were set up along the border between the Tarim basin and the Kunlun Mountains covering an area of 350 km by 150 km. All stations were equipped with high resolution REFTEK 72 digital recorders and very broadband STS 2 sensors. Continuous recording data at 50 samples per second were stored in large capacity hard disks and were retrieved. The field operation ended in mid September, 1999. In total, the authors collected more than 200 teleseismic events. The crust under Tarim basin is relatively simple. The Moho discontinuity was mapped at a depth of 42 km near the northern end of the array, which dips gently southward to some 50 km beneath the Kunlun foreland. The Tarim basin appears to be rigid, with little shortening. Further southward, the imaging reveals a complex of reflectors in the lower crust and the upper mantle. There are both north and south dipping upper mantle structures under the Kunlun foreland and Kunlun Mountains region. It is found that the observations are quite consistent with a model of lithosphere collision in which the crust and the upper mantle on both sides interpenetrate and deform each other. |
| GUAN Ye,GAO Hong,GAO Rui,RAO Rui-jun,SHI Da-nian,CHEN Rong-lu,LI Li-jun.2001.Broadband Seismic Obsevational Experiments from Tarim Basin to Kulun Mountains[J].Acta Geoscientica Sinica,22(6):559-562. |
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