The Fine Structure of the Subducted Investigator Fracture Zone in Western Sumatra as Seen by Local Seismicity
The Fine Structure of the Subducted Investigator Fracture Zone in Western Sumatra as Seen by Local Seismicity
复制标题
DOI：
10.1016/j.epsl.2010.07.020
复制
发表时间：
2010-09-15
影响因子：
5.3
通讯作者：
Ryberg, Trond
中科院分区：
文献类型：
--
作者：
Lange, Dietrich;Tilmann, Frederik;Ryberg, Trond
苏门答腊边缘近年来遭受了三次大地震（2004年12月26日亚齐-安达曼地震，Mw = 9.1; 2005年3月28日尼亚斯地震，Mw = 8.7; 2007年9月12日本库鲁地震，Mw = 8.5）。在这里，我们提出了当地的地震数据，从一个密集的，两栖的当地地震网络覆盖的Summarte边缘，最后在1797年破裂的一段。沿着苏门答腊边缘的这一部分出现的弧前岛屿沿着允许在逆冲断层的浅部之上部署地震陆地台站。这种台站几何结构与海底地震仪相结合，在一个也有大地测量数据的地区为孕震区的上倾端提供了高质量的震源位置。在这个区域，调查员断裂带（IFZ），其中包括4个子脊，是俯冲下方的巽他板块。这种地形似乎会影响所有深度间隔的地震活动。沿着间隔紧密的IFZ次脊的延长线，有一条从80公里到200公里深度的明确的线性地震活动带。更多的中深度地震活动位于这一地震活动串的东南部，与俯冲的粗糙海底有关。西比路岛下的板块界面最后一次破裂是在1797年，其特点是几乎完全没有地震活动。(C)2010爱思唯尔有限公司版权所有。
The Sumatran margin suffered three great earthquakes in recent years (Aceh-Andaman 26 December 2004 Mw = 9.1, Nias 28 March 2005 Mw = 8.7, Bengkulu 12 September 2007 Mw = 8.5). Here we present local earthquake data from a dense, amphibious local seismic network covering a segment of the Sumatran margin that last ruptured in 1797. The occurrence of forearc islands along this part of the Sumatran margin allows the deployment of seismic land-stations above the shallow part of the thrust fault. In combination with ocean bottom seismometers this station geometry provides high quality hypocentre location for the updip end of the seismogenic zone in an area where geodetic data are also available. In this region, the Investigator Fracture Zone (IFZ), which consists of 4 sub-ridges, is subducted below the Sunda plate. This topography appears to influence seismicity at all depth intervals. A well-defined linear streak of seismicity extending from 80 to 200 km depth lies along the prolongation of closely spaced IFZ sub-ridges. More intermediate depth seismicity is located to the southeast of this string of seismicity and is related to subducted rough oceanic seafloor. The plate interface beneath Siberut Island which ruptured last in 1797 is characterised by almost complete absence of seismicity. (C) 2010 Elsevier B.V. All rights reserved.