气候变化领域集成服务门户(CCPortal): A geophysical study of the Castle Mountain Fault, southcentral Alaska

CCPortal

DOI	10.1016/j.tecto.2020.228567
	A geophysical study of the Castle Mountain Fault, southcentral Alaska
	Ziwu F.D.; Doser D.I.; Schinagel S.M.
发表日期	2020
ISSN	00401951
卷号	789
英文摘要	The Castle Mountain Fault (CMF) lies less than 50 km from Alaska's most populous city of Anchorage and represents an important seismic hazard to the Anchorage-Matanuska-Susitna Valley region in southcentral Alaska. The character of seismicity varies along the CMF. Although the western CMF (between 149.5° and 151° W) shows evidence for Late Pleistocene or Holocene reverse and dextral movement, it has been seismically quiet over the past ~50 years of local seismic network operation. In contrast, the CMF east of 149.5° W is associated with considerable background seismicity, including the Mw 5.81984 strike-slip Sutton earthquake. We have used gravity and magnetic data, constrained with results of previous seismic reflection and seismic tomography studies, to model subsurface structure of the CMF in an effort to determine what may control the variation in its seismic behavior. Our models are consistent with a component of high angle reverse faulting (northwest side up, dip~85°to 87°) that appears to have vertically offset Late Mesozoic rocks 2000 to 2500 m. Lack of data coverage precludes an estimate of its total strike-slip motion. Holocene movement on the CMF appears to be associated with a region where both sides of the fault consist of sedimentary rocks as defined by a gravity and magnetic low. If most of the vertical offset has occurred since the Miocene in response to collision of the Yakutat microplate with North America, then our results are comparable to recent thermochronological and paleoseismic estimates of vertical slip rates. Subduction of the edge of the Yakutat microplate appears to spatially influence seismic behavior along the CMF while the occurrence of the 1964 Great Alaska earthquake has also temporally affected local seismicity. © 2020 Elsevier B.V.
关键词	Earthquakes Gravity Magnetics South-central Alaska
英文关键词	Anchorages (foundations); Earthquakes; Landforms; Sedimentary rocks; Seismic response; Strike-slip faults; Alaska earthquakes; Late Pleistocene; Reverse faulting; Seismic networks; Seismic reflections; Seismic tomography; Strike-slip motion; Subsurface structures; Fault slips; collision zone; earthquake event; microplate; reverse fault; sedimentary rock; seismic hazard; seismicity; slip rate; strike-slip fault; Alaska; Matanuska Valley; Susitna Valley; United States
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207921
作者单位	Department of Geological Sciences, University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968-0555, United States
推荐引用方式 GB/T 7714	Ziwu F.D.,Doser D.I.,Schinagel S.M.. A geophysical study of the Castle Mountain Fault, southcentral Alaska[J],2020,789.
APA	Ziwu F.D.,Doser D.I.,&Schinagel S.M..(2020).A geophysical study of the Castle Mountain Fault, southcentral Alaska.Tectonophysics,789.
MLA	Ziwu F.D.,et al."A geophysical study of the Castle Mountain Fault, southcentral Alaska".Tectonophysics 789(2020).