印尼附近海域地震海啸发生的构造背景综述

Summary on the tectonic setting of the area around Indonesia where earthquake tsunami happened

2004年12月26日在印度尼西亚苏门答腊岛以西海域发生的里氏9级地震,引发了历史上第五大地震海啸,引起了地学界的高度关注。印度尼西亚西部位于环太平洋地震带和地中海-喜马拉雅地震带结合部位,处于洋壳和陆壳的汇聚边界以及弧状压缩构造格局中。苏门答腊陆缘NW—SE向延伸约1600km,苏门答腊俯冲带源于印度-澳大利亚和欧亚板块3°N的汇聚。苏门答腊弧前区沿着平行于俯冲海沟的两大走滑断裂——苏门答腊大断裂和明打威断裂向北运动。本文对印度尼西亚苏门答腊岛附近海域的地质背景、大地构造特征和地震活动评估等进行了综述,对该海域产生大地震的深部动力学机制进行了分析,并从地质、地球物理资料的获取与分析角度出发,对区域灾害模型进行了探讨。

On December 26, 2004, a horrendous earthquake of over 9 on the Richter scale occurred in South Asia, triggering a tsunami wave that rose to over 45 feet high in some beach areas. The most affected countries are Sri Lanka, India, Indonesia and Thailand. The tsunami also swept across many low-lying coasts from Malaysia and Myanmar and islands like the ones that make up the Maldives. The toll of the victims has gone over 225 000, with 132 000 still missing, as of the end of January, 2005. The final death toll could approach one million. The 9-magnitude earthquake struck off the coast of the Sumatra island of Indonesia which triggered a remarkably destroying tsunami. Global cataclysms have occurred in the earth＇s past, which have shaken the nations to their core. Hard knocks Teach hard lessons. The earthquake tsunami gets attention of more and more geologists and other scientists. The Sumatra island is located in the circum-Pacific earthquake belt which includes Taiwan province and southeast sea region in east China. The earthquake belt is under the compression due to convergence between oceanic crust and continent. The geological and geophysical setting of the eastern part of China is so similar to those of the Sumatra. Furthermore, the north-south earthquake belt in China is in the north of the Sumatra subduction zone. Therefore, China should pay more attention on this issue. This paper mainly introduces geologic setting, structural evolution and features, earthquake tsunami setting and deep-seated tectonic dynamics in the vicinity of the Sumatra island of Indonesia. Understanding to geological setting and geophysical data is a basis to build the forecast system of tsunami and to discuss the regional disaster model. Especially the seismic profiles can reveal sedimentary architecture, paleomorphology, spatial and temporal migration of tsunami earthquake in order to help us understand a regular of tsunami earthquake. At last we discuss the theoretical base about building the forecast system of tsunami. This is also helpful to understand earthquake mechanism along the north-south earthquake zone in China.