Collaborative Research: Rheology of asthenosphere in the Kuril-Kamchatka subduction zone from postseismic GPS observations after great earthquakes

GSTDTAP

项目编号	1546998
	Collaborative Research: Rheology of asthenosphere in the Kuril-Kamchatka subduction zone from postseismic GPS observations after great earthquakes
	Mikhail Kogan
主持机构	Columbia University
项目开始年	2016
	2016-06-15
项目结束日期	2017-05-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	185000(USD)
国家	美国
语种	英语
英文摘要	The project relates to the region of the Kuril subduction zone in the northwest Pacific Ocean subject to disastrous earthquakes. In 2006-2007, a doublet of great (MW > 8) earthquakes partly ruptured one of the most conspicuous gaps in subduction-zone seismic activity. An immediate focus of this project is to acquire post-earthquake GPS measurement spanning the time period 2007-2016. These data will allow scientists to better understand the long-term earthquake cycle and will be important for understanding seismic hazards here and in other similar settings. This project will continue and strengthen collaboration between US universities and institutions of the Russian Academy of Sciences. The data provided by the project will be available for use by the broad scientific community. The complete 10-year-long data set is required to address fundamental problems: How much of the strain built up from subduction of the Pacific plate beneath the North American plate (the Sea of Okhotsk) has been released in the 2006 and 2007 Kuril earthquakes coseismically and postseismically? Is it possible to explain postseismic surface deformation at the Kuril-Kamchatka subduction zone with the linear viscous mantle or is a stress-dependent rheology required? These problems are especially important after the giant 2011 MW 9.0 Tohoku (Japan) earthquake, which made the scientists question the validity of precursors of imminent large earthquakes: location of seismic gaps (spatial gaps in seismic activity) and location of asperities (patches of high frictional locking at a subduction interface). Observations of postseismic deformation of this length are rare and can significantly improve understanding of the rheology of the mantle. Preliminary results of the 3-D modeling of viscoelastic relaxation now include the effect of slab geometry for linear and nonlinear mantle rheologies with a focus on matching station velocities observed five years and later. The proposed work will extend the modeling efforts based on a significantly increased interval of the data (>20% longer). This relatively late stage data is critical in testing the hypothesis of non-linear rheology.
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文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69659
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Mikhail Kogan.Collaborative Research: Rheology of asthenosphere in the Kuril-Kamchatka subduction zone from postseismic GPS observations after great earthquakes.2016.