Evidence of supershear during the 2018 magnitude 7.5 Palu earthquake from space geodesy
Evidence of supershear during the 2018 magnitude 7.5 Palu earthquake from space geodesy
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DOI：
10.1038/s41561-018-0296-0
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发表时间：
2019-02
影响因子：
18.3
通讯作者：
A. Socquet;J. Hollingsworth;E. Pathier;M. Bouchon
中科院分区：
文献类型：
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作者：
A. Socquet;J. Hollingsworth;E. Pathier;M. Bouchon
2018年9月28日10：02：43（协调世界时），印度尼西亚苏拉威西岛帕卢市发生7.5级地震。几分钟后，又发生了4-7米高的海啸。帕卢位于一个狭窄的拉分盆地中，周围是海拔高达2,000米的高山。这种形态是由Palu-Koro断层的释放弯曲造成的，Palu-Koro断层是一个快速移动的左旋走滑断层。在这里，我们提出的意见来自光学和雷达卫星图像，限制与地震相关的地表位移非常详细。主破裂和相关的二级结构的映射显示，滑动开始在一个结构复杂，以前未知的断层向北，向南延伸超过180公里，并通过两个主要的释放弯曲。帕卢市以南30公里的断裂部分是非常线性的，与地表的地质断层略有偏移。破裂的这一部分可容纳4-7米的大而光滑的表面滑动，没有浅滑动赤字。几乎没有余震地震活动记录从这一部分的断层。由于这些特征与已知的超剪切段的特征相似，我们得出结论，帕卢地震可能以超剪切速度破坏了这一段。
A magnitude 7.5 earthquake hit the city of Palu in Sulawesi, Indonesia on 28 September 2018 at 10:02:43 (coordinated universal time). It was followed a few minutes later by a 4–7-m-high tsunami. Palu is situated in a narrow pull-apart basin surrounded by high mountains of up to 2,000 m altitude. This morphology has been created by a releasing bend in the Palu-Koro fault, a rapidly moving left-lateral strike-slip fault. Here we present observations derived from optical and radar satellite imagery that constrain the ground surface displacements associated with the earthquake in great detail. Mapping of the main rupture and associated secondary structures shows that the slip initiated on a structurally complex and previously unknown fault to the north, extended southwards over 180 km and passed through two major releasing bends. The 30 km section of the rupture south of Palu city is extremely linear, and slightly offset from the mapped geological fault at the surface. This part of the rupture accommodates a large and smooth surface slip of 4–7 m, with no shallow slip deficit. Almost no aftershock seismicity was recorded from this section of the fault. As these characteristics are similar to those from known supershear segments, we conclude that the Palu earthquake probably ruptured this segment at supershear velocities.