四川中西部地区地壳结构与重力均衡
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摘要
汶川M_s8.0地震的"孕育"、发生和发展是深部物质分异、调整和运移的产物.为此,在四川中西部地区(松潘—甘孜,龙门山断裂系和四川盆地)应用重力布格异常场资料并通过两条典型剖面的地壳厚度(Moho界面深度)分布与依据Airy均衡理论给出的理论均衡地壳厚度做对比分析,探讨四川盆地、龙门山造山带、邛崃山等川西地域的地壳均衡状态,得到龙门山及其以西地带的深部地壳结构.龙门山造山带恰处于很不均衡的状态,即与其西北和东南部相比差异明显,故地壳处于不稳定状态.为探讨该区重力场均衡与强烈地震活动之间的关系,还必须进行新一轮的高精度观测,以对该区深部精细结构、重力场效应和均衡补偿深入研究.此外,本文研究结果有益于震后确定城镇布局和为不同类型建筑物重建选址提供深部要素.
The genearation, occurrence and development of Wenchuan M_S 8. 0 great earthquake was the product of decomposition, adjustment and movement of the deep material. Therefore, two profiles of crustal thickness M are obtained by using the data of Bouguer gravity anomalies. The deep crustal structures around Longmen Shan mountain fault system and its adjacent area are obtained. Meanwhile, the theoretic isostatic crustal thickness D are obtained according to Airy s isostatic theory, to research the crustal isostatic state in Sichuan Basin, Longmen Shan, Qionglai Shan and western Sichuan mountains area. After that, the distributions of D and M in this area are compared mutually. The results indicated that Longmen Shan orogenic zone is in a very non- isostatic state, i. e. , the crust is in a unstable state. There obvious differences between the orogenic zone and its north-west or south-east parts are existed. The precise deep structure, effect of gravity field and isostatic compensation must be researched, for the study of the relationship of gravity field effect and strong earthquakes. This research result may provide deep factors for the selection of location, re-construction of buildings, layout of towns and villages after earthquake.
The genearation, occurrence and development of Wenchuan M_S 8. 0 great earthquake was the product of decomposition, adjustment and movement of the deep material. Therefore, two profiles of crustal thickness M are obtained by using the data of Bouguer gravity anomalies. The deep crustal structures around Longmen Shan mountain fault system and its adjacent area are obtained. Meanwhile, the theoretic isostatic crustal thickness D are obtained according to Airy s isostatic theory, to research the crustal isostatic state in Sichuan Basin, Longmen Shan, Qionglai Shan and western Sichuan mountains area. After that, the distributions of D and M in this area are compared mutually. The results indicated that Longmen Shan orogenic zone is in a very non- isostatic state, i. e. , the crust is in a unstable state. There obvious differences between the orogenic zone and its north-west or south-east parts are existed. The precise deep structure, effect of gravity field and isostatic compensation must be researched, for the study of the relationship of gravity field effect and strong earthquakes. This research result may provide deep factors for the selection of location, re-construction of buildings, layout of towns and villages after earthquake.
引文
[1] 滕吉文.地球内部物质、能量交换与资源和环境灾害.地学前缘,2001,8(3) :1-8 Teng J W. The exchange of substance and energy, different sphere coupling and deep dynamical process within the earth. Earth Science Frontiers (in Chinese), 2001, 8(3) :1-8
[2] 滕吉文,白登海,杨辉等.汶川M_s8． 0强烈地震发生的深层过程和动力学响应.地球物理学报,2008,51(5) :1-28 Teng J W, Bai D H, Yang H, et al. The deep process and dynamic response of Wenchuan M_s8． 0 earthquake. Chinese J.Geophys. (in Chinese), 2008, 51(5) : 1-28
[3] 滕吉文.地震“孕育”、发生和发展的深部介质和构造环境的探讨.见:第四届海峡两岸地震科技研讨会,即台湾地区强地面运动观测研讨会(四)论文集.台湾,2001． 151-153 Teng J W. Discussion on the deep media and tectonic environment of the earthquake "pregnancy" , occurence and development. In:Symposium of the 4th Seismological Science and Technology Seminar of the Cross-stait, as well as the Strong Earth Surface Motion Observation Seminar in Taiwan, 2001, 15-153, Taibei
[4] 王谦身,张赤军,安玉林等.重力学.北京:地震出版社,2003 Wang Q S, Zhang C J, An Y L, et al. Gravity. Beijing: Seismological Press, 2003
[5] 刘元龙,王谦身,武传真.喜玛拉雅山脉中部地区的地壳构造及其地质意义探讨.地球物理学报,1977,20(2) :143-149 Liu Y L, Wang Q S, Wu C Z. A preliminary study of the crustal structure and the geological significance of the central portion of the Himalayan mountain region. Chinese J. Geophys. (in Chinese), 1977, 20(2) :143-149
[6] 中国地质调查局发展研究中心.汶川地震灾区重力异常图.国家汶川地震专家委员会,汶川地震灾区地震地质灾害图集.北京:中国地图出版社,2008 Development and Research Center of China Geological Survey. Bouguer Gravity Anomaly Distribution Map Around Wenchuan, National Experts Committee of Wenchuan Ms8． 0 Earthquake, Atlas of the Seismology and Geological Disaster Around Wenchuan Earthquake Region. Beijing: Sinomaps Press, 2008
[7] 王椿镛,楼海,吕智勇等.青藏高原东部地壳上地幔S波速度结构.中国科学(D辑),2008,38(1) :22-32 Wang C Y, Lou H, Lu Z Y, et al. S wave velocity structure of upper mantle beneath the eastern part of Tibetan plateau. Science in China (Series D) (in Chinese), 2008, 38(1) : 22-32
[8] 楼海,王椿镛.川滇地区重力异常的小波分析与解释.地震学报,2005,27(5) :515-523 Lou H, Wang C Y. Wavelet analysis and interpretation of gravity data in Sichuan-Yunnan region, China. Acta Seismologica Sinica (in Chinese), 2005, 27(5) : 515-523
[2] 滕吉文,白登海,杨辉等.汶川M_s8． 0强烈地震发生的深层过程和动力学响应.地球物理学报,2008,51(5) :1-28 Teng J W, Bai D H, Yang H, et al. The deep process and dynamic response of Wenchuan M_s8． 0 earthquake. Chinese J.Geophys. (in Chinese), 2008, 51(5) : 1-28
[3] 滕吉文.地震“孕育”、发生和发展的深部介质和构造环境的探讨.见:第四届海峡两岸地震科技研讨会,即台湾地区强地面运动观测研讨会(四)论文集.台湾,2001． 151-153 Teng J W. Discussion on the deep media and tectonic environment of the earthquake "pregnancy" , occurence and development. In:Symposium of the 4th Seismological Science and Technology Seminar of the Cross-stait, as well as the Strong Earth Surface Motion Observation Seminar in Taiwan, 2001, 15-153, Taibei
[4] 王谦身,张赤军,安玉林等.重力学.北京:地震出版社,2003 Wang Q S, Zhang C J, An Y L, et al. Gravity. Beijing: Seismological Press, 2003
[5] 刘元龙,王谦身,武传真.喜玛拉雅山脉中部地区的地壳构造及其地质意义探讨.地球物理学报,1977,20(2) :143-149 Liu Y L, Wang Q S, Wu C Z. A preliminary study of the crustal structure and the geological significance of the central portion of the Himalayan mountain region. Chinese J. Geophys. (in Chinese), 1977, 20(2) :143-149
[6] 中国地质调查局发展研究中心.汶川地震灾区重力异常图.国家汶川地震专家委员会,汶川地震灾区地震地质灾害图集.北京:中国地图出版社,2008 Development and Research Center of China Geological Survey. Bouguer Gravity Anomaly Distribution Map Around Wenchuan, National Experts Committee of Wenchuan Ms8． 0 Earthquake, Atlas of the Seismology and Geological Disaster Around Wenchuan Earthquake Region. Beijing: Sinomaps Press, 2008
[7] 王椿镛,楼海,吕智勇等.青藏高原东部地壳上地幔S波速度结构.中国科学(D辑),2008,38(1) :22-32 Wang C Y, Lou H, Lu Z Y, et al. S wave velocity structure of upper mantle beneath the eastern part of Tibetan plateau. Science in China (Series D) (in Chinese), 2008, 38(1) : 22-32
[8] 楼海,王椿镛.川滇地区重力异常的小波分析与解释.地震学报,2005,27(5) :515-523 Lou H, Wang C Y. Wavelet analysis and interpretation of gravity data in Sichuan-Yunnan region, China. Acta Seismologica Sinica (in Chinese), 2005, 27(5) : 515-523
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