2004年12月26日苏门答腊特大地震是过去50年间在俯冲带发生的第三大地震。其破裂开始于锡默卢岛西北部30～40km深处(Lay et al,2005),传播1300km至安达曼群岛北部(Ammon et al,2005)。这次大地震是由俯冲的印度-澳大利亚板块与上部的巽...2004年12月26日苏门答腊特大地震是过去50年间在俯冲带发生的第三大地震。其破裂开始于锡默卢岛西北部30～40km深处(Lay et al,2005),传播1300km至安达曼群岛北部(Ammon et al,2005)。这次大地震是由俯冲的印度-澳大利亚板块与上部的巽他板块之间界面的突然滑动引起的(Rhie et al,2007;Vigny et al,2005)。尽管俯冲界面结构的详细认识对于确定大型逆冲地震潜在源非常重要,但是,目前为止可用的数据(Henstock et al,2006;Sibuet et al,2007;Dewey et al,2007;Engdahlet al,2007)还无法提供这样的信息。本文展示了震源区一条高质量的地震剖面,其展布从深海平原向下延伸到弧前下面40km。地震数据显示,俯冲地壳和大洋莫霍面(地壳-地幔边界)被陆向倾斜的逆冲断层损坏并移位,意味着此大型逆冲断层目前位于大洋地幔内。我们对增生楔前缘的活动逆冲断层成像,其特点与陡峭倾斜面上的逆冲型余震一致。我们的观测结果表明,是壳幔间的强耦合导致地幔岩石脆性破裂,从而引发此次异常大的地震。展开更多
Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic sur...Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.展开更多
Intracontinental deformation is one of the most interesting problems in tectonics. But so far little attention has been paid to rock deformation, metamorphism and magmatism related with large-scale displacement and ro...Intracontinental deformation is one of the most interesting problems in tectonics. But so far little attention has been paid to rock deformation, metamorphism and magmatism related with large-scale displacement and rotation of these blocks. In this note, we take the Ailaoshan-Red River fault (ARF)zone in western Yunnan as an example and discuss the kinematics and dynamics of the fault With its neighbouring blocks in the Tertiary.展开更多
文摘2004年12月26日苏门答腊特大地震是过去50年间在俯冲带发生的第三大地震。其破裂开始于锡默卢岛西北部30～40km深处(Lay et al,2005),传播1300km至安达曼群岛北部(Ammon et al,2005)。这次大地震是由俯冲的印度-澳大利亚板块与上部的巽他板块之间界面的突然滑动引起的(Rhie et al,2007;Vigny et al,2005)。尽管俯冲界面结构的详细认识对于确定大型逆冲地震潜在源非常重要,但是,目前为止可用的数据(Henstock et al,2006;Sibuet et al,2007;Dewey et al,2007;Engdahlet al,2007)还无法提供这样的信息。本文展示了震源区一条高质量的地震剖面,其展布从深海平原向下延伸到弧前下面40km。地震数据显示,俯冲地壳和大洋莫霍面(地壳-地幔边界)被陆向倾斜的逆冲断层损坏并移位,意味着此大型逆冲断层目前位于大洋地幔内。我们对增生楔前缘的活动逆冲断层成像,其特点与陡峭倾斜面上的逆冲型余震一致。我们的观测结果表明,是壳幔间的强耦合导致地幔岩石脆性破裂,从而引发此次异常大的地震。
基金zupported by the Nati onal Natural Science Foundation ofChina(Gramt No.49972070).
文摘Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.
基金Project supported by the National Natural Science Foundation of China and C. N. R. S., France.
文摘Intracontinental deformation is one of the most interesting problems in tectonics. But so far little attention has been paid to rock deformation, metamorphism and magmatism related with large-scale displacement and rotation of these blocks. In this note, we take the Ailaoshan-Red River fault (ARF)zone in western Yunnan as an example and discuss the kinematics and dynamics of the fault With its neighbouring blocks in the Tertiary.
