| 川滇及周边地区地壳横波衰减的成像研究 |
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| 引用本文： | 马宏生, 汪素云, 裴顺平, 刘杰, 华卫, 周龙泉. 川滇及周边地区地壳横波衰减的成像研究[J]. 地球物理学报, 2007, 50(2): 465-471, |
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| 作者姓名： | 马宏生 汪素云 裴顺平 刘杰 华卫 周龙泉 |
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| 作者单位： | 1 中国地震局地震预测研究所,北京 100036 2 中国地震局地球物理研究所,北京 100081 3 中国科学院青藏高原研究所,北京 100085 4 中国地震台网中心,北京 100036 5 广东省地震局,广州 510070 |
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| 摘 要： | 利用由149个台站记录的中国地震年报、四川和云南区域地震台网观测报告的5897个近震的27530条横波振幅与周期资料，反演得到川滇地区及周边的地壳衰减Q0值（频率为1 Hz时的Q值）空间分布图像、台站的场地响应以及由于介质衰减不同造成的震级偏差.结果表明，川滇及周边地区的地壳横波衰减Q0值在200～600范围内变化，平均值为400，横向变化显著.在川西-滇西北-保山地区、云贵交界-昆明-思茅地区以及海原-祁连、汾渭和东昆仑等活动块体边界带的Q0值明显较低，这些地区地震和构造活动相对活跃；而构造相对稳定的四川盆地、马尔康块体、桂西滇东断块以及鄂尔多斯、秦岭-大别等地区的Q0值则明显较高.此外，川滇地区大多数台站的场地响应都在1附近，仅有少数增益或衰减较大，达到2倍左右，且其分布无明显规律性.该区观测报告给出的大多数地震震级偏差不大于0.3，但也有少数震级偏差达0.4，其分布与介质品质因子Q0值分布相关，说明震级测定可能受地壳介质衰减横向变化的影响.
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| 关 键 词： | 川滇及邻区 横波衰减 振幅与周期 空间成像 |
| 收稿时间： | 2005-07-31 |
Q0 tomography of S wave attenuation in Sichuan-Yunnan and adjacent regions |
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| MA Hong-Sheng, WANG Su-Yun, PEI Shun-Ping, LIU Jie, HUA Wei, ZHOU Long-Quan. Q0 tomography of S wave attenuation in Sichuan-Yunnan and adjacent regions[J]. Chinese Journal of Geophysics (in Chinese), 2007, 50(2): 465-471, |
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| Authors: | MA Hong-Sheng WANG Su-Yun PEI Shun-Ping LIU Jie HUA Wei ZHOU Long-Quan |
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| Affiliation: | 1 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China 2 Institute of Geophysics, China Earthquake Administration, Beijing 100081 China 3 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 4 China Earthquake Network Center, China Earthquake Administration, Beijing 100036, China 5 Earthquake Administration of Guangdong Province, Guangzhou 510070, China |
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| Abstract: | We have selected 27530 ML amplitude readings from 5897 events recorded by 149 stations, as reported in the Annual Bulletin of Chinese Earthquakes (ABCE) and regional seismic network of Yunnan province and Sichuan province, and have used tomographic imaging to estimate the lateral variations of the quality factor Q0 (Q at 1 Hz) in the crust of Sichuan-Yunnan and its adjacent regions. Estimated Q0 values vary from 200 to 600 with an average of 400. Q0 values are consistent with tectonic and topographic structure. Q0 is low in the active tectonic regions having many faults, such as the Haiyuan-Qilian, Fenhe-Weihe, East Kunlun zones, Western Sichuan-Northwestern Yunnan-Baoshan area and joint of Yunnan and Guizhou-Kunming-Simao area. Q0 is high in the stable regions, such as Sichuan Basin, Markam block, Western Guangxi-Eastern Yunnan block, Ordos Craton and Qinling-Dabie area. Additionally, The gains of most of the station terms in Sichuan-Yunnan and its adjacent regions are near 1.0, only a few as large as 2.0, and the distribution is irregular. Most of the magnitude biases are less than 0.3, only a few as large as 0.4, and the distribution has relation with the Q0 values distribution, which means that the crustal attenuation has influence on the magnitude measurement. |
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| Keywords: | Sichuan-Yunnan S wave attenuation Amplitude and period Tomography |
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