Using uplifted Holocene beach berms for paleoseismic analysis on the Santa Maria Island, south-central Chile
Using uplifted Holocene beach berms for paleoseismic analysis on the Santa Maria Island, south-central Chile
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DOI：
10.1029/2006gl026734
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发表时间：
2006-08-02
影响因子：
5.2
通讯作者：
Spencer, J. Q. G.
中科院分区：
文献类型：
--
作者：
Bookhagen, B.;Echtler, H. P.;Spencer, J. Q. G.
大地震（M > 8）多次使智利中南部的纳斯卡-南美洲板块界面破裂，导致米级土地平面变化。然而，超出有限历史记录的地震复发间隔实际上是未知的，但它将提供有关弧前构造行为的重要数据。我们分析了圣玛丽亚岛（SMI；南纬 37 度）全新世地震的时空模式，该岛距离智利海岸 20 公里，海沟以东约 70 公里。 SMI 至少拥有 21 个隆起的海滩护堤，其中一部分经测算，平均隆起率为 2.3 +/- 0.2 m/ky，倾斜率为 0.022 +/- 0.002 度/ky。推断的股线形成地震的复发间隔大约为 180 年。结合地震周期期间的同震抬升和抗震沉降，该环境中岸线高程的净增益类似于每次事件 0.4 m。
Major earthquakes ( M > 8) have repeatedly ruptured the Nazca-South America plate interface of south-central Chile involving meter scale land-level changes. Earthquake recurrence intervals, however, extending beyond limited historical records are virtually unknown, but would provide crucial data on the tectonic behavior of forearcs. We analyzed the spatiotemporal pattern of Holocene earthquakes on Santa Maria Island (SMI; 37 degrees S), located 20 km off the Chilean coast and approximately 70 km east of the trench. SMI hosts a minimum of 21 uplifted beach berms, of which a subset were dated to calculate a mean uplift rate of 2.3 +/- 0.2 m/ky and a tilting rate of 0.022 +/- 0.002 degrees/ky. The inferred recurrence interval of strandline-forming earthquakes is similar to 180 years. Combining coseismic uplift and aseismic subsidence during an earthquake cycle, the net gain in strandline elevation in this environment is similar to 0.4 m per event.