拉萨和羌塘地块地震活动和热前兆现象及其机理研究

地震 ›› 2010, Vol. 30 ›› Issue (1): 20-27.

拉萨和羌塘地块地震活动和热前兆现象及其机理研究

傅征祥¹, 吕晓健¹, 张元生², 金学申³, 邵辉成⁴

1.中国地震局地震预测研究所, 北京 100036;
2.甘肃省地震局, 甘肃兰州 730000;
3.河北省地震局, 河北石家庄 050021;
4.陕西省地震局, 陕西西安 710068

收稿日期:2009-06-11 修回日期:2009-09-03 出版日期:2010-01-31 发布日期:2021-10-15
作者简介:傅征祥(1941-), 男, 上海市人, 研究员, 主要从事地震活动性和地震预测研究。
基金资助:
国家重点基础研究发展计划(973计划)“汶川地震发生机理及其大区动力环境研究”, 课题“中亚大陆强震构造格局及其动力学环境”(2008CB425703)

Seismicity and Precursory Heat Anormaly in the Lasa and Qiangtang Blocks

FU Zheng-xiang¹, LU Xiao-jian¹, ZHANGYuan-sheng², JIN Xue-shen³, ZHAO Hui-cheng⁴

1. Institute of Earthquake Science, CEA, Beijing 100036, China;
2. Lanzhou Institute of Seismology, CEA, Lanzhou 730000, China;
3. Hebei Seismological Bureau, Shijiazhuan 050021, China;
4. Shanxi Seismological Bureau, Xian 710068, China

Received:2009-06-11 Revised:2009-09-03 Online:2010-01-31 Published:2021-10-15

摘要/Abstract

摘要： 青藏地块活动区南部的II级拉萨和羌塘地块内部的M≥6.5强震活动比北部的巴颜喀拉、柴达木和祁连II级地块内部明显活跃, 这可能与拉萨和羌塘地块处于地壳厚度较大、较高的热状态和较低的正断层剪切强度等地学背景下, 导致地壳强度较弱有关。拉萨和羌塘地块内部两次拉张性正断层活动的强震(2008年于田7.3级和当雄6.6级)前热异常的震例, 可能与临震前孕震区及邻近断层带扩容, 以及中下地壳低速层熔融物质或流体的进入有关。

关键词: 拉萨和羌塘地块内部, 强震活动, 强震前热异常, 构造活动

Abstract: There are relatively active strong seismicity inside the second-order Lasa and Qiangtang blocks compared with other blocks in the first-order Qing-Zang active block region, which might be related to the weaker crust strength due to thicker crust, higher heat and lower shear strength on normal fault there. Inside the second-order Lasa and Qiangtang active blocks, cases of abnormal heat phenomenon have been observed before two strong earthquakes(M7.3 Yutian earthquake and M6.6 Danxion earthquake in 2008) , which might be related to the dilatation in the faults of earthquake preparation region and nearby, where melting material and liquid enter into from the low velocity layer in upper-middle crust.

Key words: Lasa and Qiangtang blocks, Strong earthquake activity, Precursory heat anormaly, Tectonic activity

中图分类号:

P315.7

傅征祥, 吕晓健, 张元生, 金学申, 邵辉成. 拉萨和羌塘地块地震活动和热前兆现象及其机理研究[J]. 地震, 2010, 30(1): 20-27.

FU Zheng-xiang, LU Xiao-jian, ZHANGYuan-sheng, JIN Xue-shen, ZHAO Hui-cheng. Seismicity and Precursory Heat Anormaly in the Lasa and Qiangtang Blocks[J]. EARTHQUAKE, 2010, 30(1): 20-27.

参考文献

[1] 张培震, 邓起东, 张国民, 等. 中国大陆的强震活动与活动地块[J]. 中国科学(D辑), 2003, 33(增刊): 12-20.
[2] Tsapanos T M, Papazachos B C. Geographical and vertical variation of the earth's seismicity[J]. J Seismology, 1998, 2: 183-192.
[3] Armijo R, Tapponnier P, Mercier J L, et al. Quaternary extension in southern Tibet: field observation and tectonic implication[J]. J Geophys Res, 1986, 91(B14): 13803-13872.
[4] 中国地震局地质研究所. 西藏中部活动断层[M]. 北京: 地震出版社, 1992.
[5] Yin A, Kapp P A , Murphy M A, et al. Significant late Neogene east-west extension in northern Tibet[J].Geology, 1999, 25: 787-790.
[6] Braitenberg C, Zadro M, Fang J, et al. Gravity inversion in Qinghai-Tibet plateau[J]. Phys Chem Earth(A), 2000, 25(4): 381-386.
[7] Kind R, Ni J, Zhao W, et al. Evidence from Earthquake Data for a Partially Molten Crustal Layer in Southern Tibet[J]. Science, 1996, 274(5293): 1692-1694.
[8] 李永华, 曾融生, 吴庆举, 等. 青藏高原拉萨及羌塘块体的地壳结构研究[J]. 地震学报, 2006, 28(6):586-595.
[9] 江在森, 杨国华, 等. 大地形变在2006—2020年中国大陆强震危险区预测中的应用研究[A]. “2006—2020年中国大陆强震危险区与地震灾害预测研究”项目组. 2006—2020年中国大陆强震危险区与地震灾害预测研究[C]. 北京:地震出版社, 2007. 98-101.
[10] 王洪涛, 范光禄. 热震状态[A]. 马杏垣. 中国岩石圈动力学图集[C]. 北京: 地震出版社, 1989. 15.
[11] 汪素云, 高阿甲, 许忠淮, 等. 青藏高原东北地区地震重新定位及其活动特征[J]. 地震学报, 2000, 22(3):241-248.
[12] Liang Xiaofeng, Shiyong Zhou, John Chen Y, et al. Earthquake distribution in southern Tibet and its tectonic implications[J]. J Geopgys Res, 2008, 113, B12409, doi: 10. 1029/2007 JB005101.
[13] Molnar P, Tapponnier P. Active tectonics of Tibet[J]. J Geophys Res, 1978, 85: 5361-5384.
[14] Ni J, Barazangi M. Seismotectonics of Himalayan collision zone: Geometry of underthrusting India plate beneath the Himalaya[J]. J Geophys Res, 1984, 89: 1147-1163.
[15] 郑斯华, 高原. 青藏高原的地震学研究(综述)[A]. 马宗晋, 汪一鹏, 张燕平主编. 青藏高原岩石圈现今变动与动力学[C]. 北京:地震出版社, 2001. 223-239.
[15] Molnar P, Lyon-Caen H. Fault plane solutions of earthquakes and active tectonics of the Tibet an Plateau and its margin[J]. Geophys J Int, 1989, 99: 123-153.
[16] 许忠淮. 东亚地区现今构造应力图的编制[J]. 地震学报, 2001, 23(5):492-501.
[17] 熊熊. 青藏高原岩石圈强度的弱化[A]. 马宗晋, 汪一鹏, 张燕平主编. 青藏高原岩石圈现今变动与动力学[C]. 北京:地震出版社, 2001. 172-176.
[18] Sibson R H. Frictional constraints on thrust, wrench and normal faults[J]. Nature, 1974, 249: 542-545.
[19] Brace W F, Kohlstedt D. Limits on lithospheric stress imposed by laboratory experiments[J]. J Geophys Res, 1980, 85: 6248-6252.
[20] Kirby S. Tectonic stress in the lithosphere: Constraints provided by the experimental deformation of rock[J]. J Geophys Res, 1980, 85: 6353-6363.
[21] Scholz C H. 地震与断层力学[M]. 马胜利等译校. 北京: 地震出版社, 1996. 134.
[22] Brace W F, Paulding B W, Scholz C H. Dilatancy in the fracture of crystalline rocks[J]. J Geophys Res, 1966, 71: 3939-3953.
[23] Gaillard F, Scaillet B, Pichavant M. Evidence for present-day leucogranite pluton growth in Tibet[J]. Geology, 2004, 32(9): 801-804.
[24] Scholz C H, Sykes L R, Aggarwal Y P. Earthquake prediction: A physical basis[J]. Science, 1973, 181: 803-809.
[25] Stesky R, Brace W, Riley D, et al. Friction in faulted rock at high temperature and pressure[J]. Tectonophysics, 1974, 23: 177-203.