Uplift and subsidence reveal a nonpersistent megathrust rupture boundary
Uplift and subsidence reveal a nonpersistent megathrust rupture boundary
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DOI：
10.1002/2014gl059380
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发表时间：
2014-04-16
影响因子：
5.2
通讯作者：
Bradley, Lee-Ann
中科院分区：
文献类型：
--
作者：
Briggs, Richard W.;Engelhart, Simon E.;Bradley, Lee-Ann
我们报告了在科迪亚克岛西部的史前和历史地震期间，沿阿拉斯加-阿留申巨型逆冲断层的陆地水平变化和海啸淹没的地层证据。在锡特基纳克岛，礁湖边缘的岩心和潮汐露头揭示了五个尖锐的岩性接触，记录了同震地面的变化。放射性碳测年、Cs-137剖面、计算机断层扫描和微化石组合与大约290- 0,520 -300和1050-790calyr B.P.的快速隆起和公元1964年和大约640-510calyr B.P.的沉降相一致。放射性碳、Cs-137和Pb-210年龄包围了内陆1.5公里处的沙床，而突然隆起的证据与俄罗斯对公元1788年地震和海啸的描述相一致。混合隆升和沉降记录表明，锡特基纳克岛位于公元1964年m - w9.2大逆冲断裂西南边界附近的非持续性边界之上。
We report stratigraphic evidence of land-level change and tsunami inundation along the Alaska-Aleutian megathrust during prehistoric and historical earthquakes west of Kodiak Island. On Sitkinak Island, cores and tidal outcrops fringing a lagoon reveal five sharp lithologic contacts that record coseismic land-level change. Radiocarbon dates, Cs-137 profiles, computerized tomography scans, and microfossil assemblages are consistent with rapid uplift circa 290-0, 520-300, and 1050-790calyr B.P. and subsidence in A.D. 1964 and circa 640-510calyr B.P. Radiocarbon, Cs-137, and Pb-210 ages bracketing a sand bed traced 1.5km inland and evidence for sudden uplift are consistent with Russian accounts of an earthquake and tsunami in A.D. 1788. The mixed uplift and subsidence record suggests that Sitkinak Island sits above a nonpersistent boundary near the southwestern limit of the A.D. 1964 M-w 9.2 megathrust rupture.