A Possible Source Mechanism of the 1946 Unimak Alaska Far-Field Tsunami: Uplift of the Mid-Slope Terrace Above a Splay Fault Zone
A Possible Source Mechanism of the 1946 Unimak Alaska Far-Field Tsunami: Uplift of the Mid-Slope Terrace Above a Splay Fault Zone
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1946 年乌尼马克阿拉斯加远场海啸的可能来源机制：张开断层带上方中坡台地的隆起
DOI：
10.1007/s00024-016-1393-x
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发表时间：
2016
影响因子：
2
通讯作者：
P. Dartnell
中科院分区：
文献类型：
--
作者：
R. von Huene;John J. Miller;D. Klaeschen;P. Dartnell
1946年，沿阿拉斯加俯冲带尤尼马克段的大型逆冲地震活动产生了有史以来最大的阿拉斯加/阿留申海啸。海啸严重破坏了从阿拉斯加到南极洲的太平洋岛屿和沿海地区。它是“海啸”地震的创始成员，这些地震产生的远场海啸的震级超过了记录的震级。其来源机制不受观测的约束，因为Unimak段的地球物理数据稀疏且分辨率低。对遗留地球物理数据的再处理表明，深水、高角度逆冲或展斜逆冲断裂带导致巨型逆冲断层向上滑向中斜坡阶地海底，而不是沿着板块边界向海沟轴方向滑向。扇形断层隆升使外中坡阶地抬升，内坡阶地下沉。沿展状断裂带的多波束测深显示了最近但未确定日期的海底破坏。附近的半米迪段的结构形态与尤尼马克段相似，预示着未来会产生一场指向美国西海岸的大海啸。
In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of “tsunami” earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.
2010 年智利中部 Mw 8 8 Maule 地震的余震揭示了张开断层活动
影响因子：
5.8
作者：
Lieser;Grevemeyer;Tilmann;Contreras-Reyes
通讯作者：
Contreras-Reyes