气候变化领域集成服务门户(CCPortal): Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust

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DOI	10.1130/B32031.1
	Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust
	Witter R.; Briggs R.; Engelhart S.E.; Gelfenbaum G.; Koehler R.D.; Nelson A.; Selle S.L.; Corbett R.; Wallace K.
发表日期	2019
ISSN	167606
起始页码	707
结束页码	729
卷号	131 期号:2021-05-06
英文摘要	At the eastern end of the 1957 Andreanof Islands, Alaska, USA, moment magnitude 8.6 earthquake rupture, Driftwood Bay (Umnak Island) and Stardust Bay (Sedanka Island) lie along presently locked and creeping parts of the Aleutian megathrust, respectively, based on satellite geodesy onshore. Both bays, located 200 km apart, face the Aleutian trench and harbor coastal evidence for tsunami inundation in 1957. Here we describe the evidence at Driftwood Bay, including eight sheets of landward-fining, normally-graded marine sand that extend up to 375 m inland and 23 m above mean tide level. Drift logs that corroborate historical accounts of 1957 tsunami runup on Umnak Island's Pacific coast overlie the youngest sand sheet, which 137Cs activity shows was deposited in the decade before 1963. The older sand sheets probably record tsunamis prior to 1957 because an emergent coastal terrace lacks evidence for storm-wave erosion and overwash since ca. 2 ka. Comparisons of the Driftwood Bay and Stardust Bay tsunami histories suggest that at least twice in the past 1700 years inundation occurred at one site but not the other. In contrast, Bayesian age-depth modeling suggests that the two bays may record five tsunamis like the 1957 tsunami, generated by earthquake ruptures that spanned the presently locked and creeping parts of the Aleutian megathrust. However, serial tsunamis occurring within days to centuries cannot be precluded. Our findings imply 164-257-year recurrence intervals for large eastern Aleutian tsunamis and challenge the notion that creeping parts of the megathrust, inferred from geodesy onshore, pose lower earthquake and tsunami hazards than locked areas. © 2018 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184923
作者单位	Alaska Science Center, U.S. Geological Survey, 4210 University Drive, Anchorage, AK 99508, United States; Geological Hazards Science Center, U.S. Geological Survey, 1711 Illinois Street, Golden, CO 80401, United States; Department of Geosciences, University of Rhode Island, 9 East Alumni Avenue, Kingston, RI 02881, United States; Pacific Coastal and Marine Science Center, U.S. Geological Survey, 400 Natural Bridges Drive, Santa Cruz, CA 95060, United States; Nevada Bureau of Mines and Geology, University of Nevada, Mail Stop 178, Reno, NV 89557, United States; Department of Geological Sciences, East Carolina University, 101 Graham Building, Greenville, NC 27858, United States; U.S. Geological Survey, Alaska Volcano Observatory, 4230 University Drive, Suite 100, Anchorage, AK 99508, United States
推荐引用方式 GB/T 7714	Witter R.,Briggs R.,Engelhart S.E.,et al. Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust[J],2019,131(2021-05-06).
APA	Witter R..,Briggs R..,Engelhart S.E..,Gelfenbaum G..,Koehler R.D..,...&Wallace K..(2019).Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust.Bulletin of the Geological Society of America,131(2021-05-06).
MLA	Witter R.,et al."Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust".Bulletin of the Geological Society of America 131.2021-05-06(2019).