Can turbidites be used to reconstruct a paleoearthquake record for the central Sumatran margin
Can turbidites be used to reconstruct a paleoearthquake record for the central Sumatran margin
复制标题
DOI：
10.1130/g34298.1
复制
发表时间：
2013-07
期刊：
影响因子：
5.8
通讯作者：
E. Sumner;M. Siti;L. McNeill;P. Talling;T. Henstock;R. Wynn;Y. Djajadihardja;H. Permana
中科院分区：
文献类型：
--
作者：
E. Sumner;M. Siti;L. McNeill;P. Talling;T. Henstock;R. Wynn;Y. Djajadihardja;H. Permana
浊积岩古地震学的目标是利用海底重力流沉积(浊积岩)作为大地震的替代物，一个关键的假设是大地震在大范围内同步产生浊流。我们测试是否所有大地震都会产生同步浊流，如果不是，则调查大地震未能做到这一点的地方。苏门答腊岛边缘过去200年的地震记录很有特色，包括2004年的大地震(9.1兆瓦)和2005年的大地震(8.7兆瓦)。2009年从苏门答腊岛中部边缘采集的沉积物岩心显示，在过去100-150年间侵位的浊积岩出奇地少，而且沉积的浊积岩并不广泛。重要的是，斜坡盆地沉积没有保存与2004年和2005年地震相关的浊积岩的证据，尽管在海沟中看到了最近的流动沉积。相邻的斜坡盆地和相邻的一对斜坡盆地和海沟遗址通常具有不同的沉积记录，不能进行对比。这些来自苏门答腊岛中部边缘的核心遗址并不支持这样的假设，即所有的大地震都会产生重建准确的古地震记录所必需的广泛的同步浊流。
Turbidite paleoseismology aims to use submarine gravity flow deposits (turbidites) as proxies for large earthquakes, a critical assumption being that large earthquakes generate turbidity currents synchronously over a wide area. We test whether all large earthquakes generate synchronous turbidites, and if not, investigate where large earthquakes fail to do this. The Sumatran margin has a well-characterized earthquake record spanning the past 200 yr, including the large-magnitude earthquakes in 2004 (Mw 9.1) and 2005 (Mw 8.7). Sediment cores collected from the central Sumatran margin in 2009 reveal that surprisingly few turbidites were emplaced in the past 100–150 yr, and those that were deposited are not widespread. Importantly, slope basin deposits preserve no evidence of turbidites that correlate with the earthquakes in 2004 and 2005, although recent flow deposits are seen in the trench. Adjacent slope basins and adjacent pairs of slope basin and trench sites commonly have different sedimentary records, and cannot be correlated. These core sites from the central Sumatran margin do not support the assumption that all large earthquakes generate the widespread synchronous turbidites necessary for reconstructing an accurate paleoearthquake record.