| 青藏高原横波分裂的观测研究 |
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| 引用本文： | 丁志峰,曾融生.青藏高原横波分裂的观测研究[J].地球物理学报,1996,39(2):211-220. |
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| 作者姓名： | 丁志峰 曾融生 |
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| 作者单位： | 国家地震局地球物理研究所, 北京 100081 |
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| 摘 要： | １９９１年７月－１９９２年６月，中、美两国合作在青藏高原架设了１１个宽频带数字记录的ＰＡＳＳＣＡＬ临时地震台站，它们分布在青藏公路沿线和青藏高原东部地区．利用这些台站记录到的高质量数据，对远震的ＳＫＳ波进行分析和计算，在多数台站观测到了ＳＫＳ波分裂的现象．用ＳＣ方法计算了青藏高原所记录到的ＳＫＳ波分裂的参量，即快波偏振方向φ和快、慢波的到时差δｔ，探求台站下地幔介质的各向异性．φ从南（拉萨）往北（至格尔木）有一趋势变化，从南边的北东方向渐变至北边的近东西方向．快、慢波的到时差在高原上向北渐渐变大，在不冻泉达到最大；再往北至格尔木又迅速减小．认为在印度板块和欧亚大陆的碰撞挤压下，雅鲁藏布江以北青藏高原下面的上地幔物质在区域构造应力场的作用下，沿东西方向发生形变以至流动，它使上地幔中橄榄岩的晶格排列方向平行于物质形变或流动的方向．
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| 关 键 词： | SKS波分裂 上地幔 各向异性 青藏高原 |
| 收稿时间： | 1994-11-09 |
OBSERVATION AND STUDY OF SHEAR WAVE ANISOTROPY IN TIBETAN PLATEAU |
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| DING ZHI_FENG,ZENG RONG-SHENG.OBSERVATION AND STUDY OF SHEAR WAVE ANISOTROPY IN TIBETAN PLATEAU[J].Chinese Journal of Geophysics,1996,39(2):211-220. |
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| Authors: | DING ZHI_FENG ZENG RONG-SHENG |
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| Affiliation: | Institute of Geophysics, State Seismological Bureau, Beijing 100081, China |
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| Abstract: | From July,1991 to June,1992，11 broadband digital PASSCAL portable seismic stations were deployed across the Tibetan Plateau cooperated by Sino-US scientists．These stations distributed along Qinghai-Xizang highway and the eastern part of the Tibetan Plateau．The teleseismic SKS waves were analyzed and measured by using the high quality data recorded in these stations．The SKS splittings were found in most stations．The SC algorithm was used to calculate the splitting parameters of SKS phases recorded in Tibetan Plateau．The parameters φ，polarized direction of the splitting fast S wave，and δt，the arrival time difference between the fast and slow S waves，were used to detect the mantle material anisotropy under the stations．It shows that φ has a trend from south（Lhasa）to North（Gulmud），i．e，from NE direction in the south to nearly EW direction in the north．Tbe arrival time difference δt increases from the south to the north in the Plateau，the largest is at Budongquan（BUDO），δt decreases rapidly from BUDO to Gulmud．We suggest that due to the collision and compression between Indian plate and Eurasia continent，the upper mantle material beneath the Tibetan Plateau in north of Yarlung Zangbo river deformed or flowed along East-west direction under the regional stress field．This makes the lattice preferred orientation in upper mantle parallel to the direction of mantle deformation or mantle flow． |
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| Keywords: | SKS wave splitting Upper mantle Anisotropy Tibetan Plateau |
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