DOI: 10.1002/2014GL059393
论文题名: Little late Holocene strain accumulation and release on the Aleutian megathrust below the Shumagin Islands, Alaska
作者: Witter R.C. ; Briggs R.W. ; Engelhart S.E. ; Gelfenbaum G. ; Koehler R.D. ; Barnhart W.D.
刊名: Geophysical Research Letters
ISSN: 0094-10167
EISSN: 1944-9898
出版年: 2014
卷: 41, 期: 7 起始页码: 2359
结束页码: 2367
语种: 英语
英文关键词: Aleutian megathrust
; paleoseismology
; seismic gap
; Shumagin Islands
Scopus关键词: Peat
; Sea level
; Tsunamis
; Co-seismic uplifts
; Geodetic observation
; Megathrust
; Paleoseismology
; Relative sea level
; Seismic gaps
; Shumagin
; Strain accumulations
; Earthquakes
; bedrock
; coseismic process
; creep
; earthquake event
; earthquake magnitude
; geodetic datum
; geological record
; Holocene
; paleoseismicity
; silt
; slip
; strain
; subduction zone
; tephra
; thrust
; tsunami
; Alaska
; Shumagin Islands
; Simeonof Island
; United States
英文摘要: Can a predominantly creeping segment of a subduction zone generate a great (M->-8) earthquake? Despite Russian accounts of strong shaking and high tsunamis in 1788, geodetic observations above the Aleutian megathrust indicate creeping subduction across the Shumagin Islands segment, a well-known seismic gap. Seeking evidence for prehistoric great earthquakes, we investigated Simeonof Island, the archipelago's easternmost island, and found no evidence for uplifted marine terraces or subsided shorelines. Instead, we found freshwater peat blanketing lowlands, and organic-rich silt and tephra draping higher glacially smoothed bedrock. Basal peat ages place glacier retreat prior to 10.4-ka and imply slowly rising (<0.2-m/ka) relative sea level since ∼3.4-ka. Storms rather than tsunamis probably deposited thin, discontinuous deposits in coastal sites. If rupture of the megathrust beneath Simeonof Island produced great earthquakes in the late Holocene, then coseismic uplift or subsidence was too small (≤0.3-m) to perturb the onshore geologic record. Key Points Simeonof Island lacks evidence for great earthquakes and tsunamis Slow sea-level rise since ∼3.4 ka was unperturbed by sudden tectonic jerks Creeping subduction in the Shumagin gap probably persisted in the late Holocene © 2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897955389&doi=10.1002%2f2014GL059393&partnerID=40&md5=d559a7dc4e86a60f87f244e598f1160f
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7431
Appears in Collections: 气候减缓与适应
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作者单位: Alaska Science Center, U.S. Geological Survey, Anchorage, AK, United States
Recommended Citation:
Witter R.C.,Briggs R.W.,Engelhart S.E.,et al. Little late Holocene strain accumulation and release on the Aleutian megathrust below the Shumagin Islands, Alaska[J]. Geophysical Research Letters,2014-01-01,41(7).