GPS解算的日本Mw9.0级地震的远场同震地表位移
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摘要
利用日本Mw9.0地震前后各3d的77个GPS连续站观测资料和JPL精密星历,计算了该地震对周缘各国及相邻板块运动的同震影响。结果显示,日本地震对日本、中国东北部、朝鲜半岛均有较大影响,其同震水平位移影响范围达2 000km,地震造成中国东北东移1～3cm,华北东移3～8mm,朝鲜半岛东移2cm。中国境内的GPS测站的垂直同震位移均呈上升趋势,但是上升幅度非常小。结合日本岛测定的GPS同震位移和约20m高的海啸可以推断,本次日本地震的同震垂直位移具有波状起伏特征,符合逆冲挤压型地震的粘弹性理论模型。鉴于近年地震活动趋势,应该密切关注横贯中国东部的深大断裂带(郯庐断裂带)的断层活动,借助中国陆态网络密集覆盖提供的有利条件,跟踪研究郯庐断裂带附近300km范围的区域地壳现今变形、应力应变场的时变过程等,分析郯庐断裂带的断层活动,捕捉异常信息。
Based on 3-day IGS and CGPS observations before and after the great Mw9.0 Tohoku earthquake,we presented the coseismic deformation field composed of 77 sites for China and surrounding area.The results show that significant displacements is detected in a wide area ranging from the Korean peninsula to the north and northeast of China.Almost all sites move forward to the epicenter.The horizontal displacement is up to 1-3 cm in the northeast of China,3-8 mm in the north China,and 2 cm in the Korean peninsula.The vertical coseismic offsets of CGPS stations in China are uplift,but the magnitudes are very small.The up-down alternate phenomenon of far and near field coseismic vertical displacement reflects its undulating characteristics.In consideration of the earthquake relevance in the identical tectonic system,we should pay close attention to the activities of the Tan-lu fault belts which across the region of eastern China with the advantages provided by the intensive cover of CGPS.
Based on 3-day IGS and CGPS observations before and after the great Mw9.0 Tohoku earthquake,we presented the coseismic deformation field composed of 77 sites for China and surrounding area.The results show that significant displacements is detected in a wide area ranging from the Korean peninsula to the north and northeast of China.Almost all sites move forward to the epicenter.The horizontal displacement is up to 1-3 cm in the northeast of China,3-8 mm in the north China,and 2 cm in the Korean peninsula.The vertical coseismic offsets of CGPS stations in China are uplift,but the magnitudes are very small.The up-down alternate phenomenon of far and near field coseismic vertical displacement reflects its undulating characteristics.In consideration of the earthquake relevance in the identical tectonic system,we should pay close attention to the activities of the Tan-lu fault belts which across the region of eastern China with the advantages provided by the intensive cover of CGPS.
引文
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[2]Qiao X,Yang S,Du R,et al.GPS-derived CrustalDeformation in Southwestern China[J].AustralianJournal of Earth Science,2007,54(4):521-529
[3]许才军,刘洋,温扬茂.利用GPS资料反演汶川Mw7.9级地震滑动分布[J].测绘学报,2009,38(3):195-201
[4]洪川,窦振亚,刘锋涛.郯庐地震带与日本海沟、琉球群岛地震带之间的地震活动群体特征联系[J].海洋地质动态,2008,24(10):1-7
[5]ARIA Team at JPL and Caltech.Preliminary GPSDisplacement Data(Ver 0.3)[OL].http://super-sites.earthobservations.org/sendai.php,2011
[6]牛之俊,游新兆,杨少敏.利用GPS分析天山现今地壳变形特征[J].大地测量与地球动力学,2007,27(2):1-9
[7]Okada Y.Surface Deformation Due to Shear andTensile Faults in a Half-space[J].Bull Seism SocAm,1985,75(4):1 135-1 154
[8]Plafker G.Tectonic Deformation Associated withthe 1964 Alaska Earthquake[J].Science,1965,148:1 675-1 687
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