DOI: 10.1016/j.epsl.2017.10.017
Scopus记录号: 2-s2.0-85033579487
论文题名: Strain partitioning in Southeastern Alaska: Is the Chatham Strait Fault active?
作者: Brothers D.S. ; Elliott J.L. ; Conrad J.E. ; Haeussler P.J. ; Kluesner J.W.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 481 起始页码: 362
结束页码: 371
语种: 英语
英文关键词: glaciomarine fjord
; GPS block modeling
; marine geology
; seismic reflection
; transform tectonics
Scopus关键词: Earthquakes
; Geophysics
; Global positioning system
; Hazards
; Hydraulic structures
; Seismic response
; Seismic waves
; Seismology
; Stratigraphy
; Strike-slip faults
; Submarine geology
; Tectonics
; Block modeling
; Controlled deposition
; glaciomarine fjord
; Marine seismic reflections
; Seismic hazard assessment
; Seismic reflection data
; Seismic reflections
; Transform plate boundary
; Faulting
; fjord
; glaciomarine deposit
; GPS
; modeling
; plate boundary
; plate motion
; seismic reflection
; slip rate
; strain partitioning
; strike-slip fault
; tectonics
; Alaska
; Alexander Archipelago
; British Columbia
; Canada
; Chatham Strait
; Lynn Canal
; United States
英文摘要: A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte–Fairweather Fault (QCFF) System, which has produced at least six M > 7 earthquakes since 1920, seismic hazard assessments also include the Chatham Strait Fault (CSF) as a potentially active, 400 km-long strike slip fault that cuts northward through southeastern Alaska, connecting with the Eastern Denali Fault. Nearly the entire length of the CSF is submerged beneath Chatham Strait and Lynn Canal and has never been systematically imaged using high-resolution marine geophysical approaches. In this study we present an integrated analysis of new marine seismic reflection data acquired across Lynn Canal and tectonic block modeling constrained by data from continuous and campaign GPS sites. Seismic profiles cross the CSF at twelve locations spanning ∼50 km of fault length; they reveal thick (up to 300 m) packages of glaciomarine sedimentary facies emplaced on an unconformity surface that formed during the Last Glacial Maximum (LGM). Localized warping of post-LGM stratigraphy (∼13.9 kyr B.P. to present) appears to correlate with sediment drape on basement topography and current-controlled deposition. There is no evidence for an active fault along the axis of Lynn Canal in the seismic reflection data. Crustal block models constrained by GPS data allow, but do not require, a maximum slip rate of 2–3 mm/yr along the CSF; higher slip rates on the CSF result in significant misfit to GPS data in the surrounding region. Based on the combined marine geophysical and GPS observations, it is plausible that the CSF has not generated resolvable coseismic deformation in the last ∼13 ka and that the modern slip-rate is <1 mm/yr. We propose that models for strain transfer between the QCFF and the Denali Fault, and seismic hazard maps in general, may need to be reevaluated. © 2017 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110189
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Pacific Coastal and Marine Science Center, U.S. Geological Survey, 400 Natural Bridges Rd., Santa Cruz, CA 95060, United States; Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, United States; Alaska Science Center, U.S. Geological Survey, 4210 University Dr., Anchorage, AK 99508, United States
Recommended Citation:
Brothers D.S.,Elliott J.L.,Conrad J.E.,et al. Strain partitioning in Southeastern Alaska: Is the Chatham Strait Fault active?[J]. Earth and Planetary Science Letters,2018-01-01,481