Collaborative Research: Improving models of interseismic locking and slow slip events in Cascadia and New Zealand

GSTDTAP

项目编号	1551876
	Collaborative Research: Improving models of interseismic locking and slow slip events in Cascadia and New Zealand
	Laura Wallace
主持机构	University of Texas at Austin
项目开始年	2016
	2016-04-01
项目结束日期	2019-03-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	86556(USD)
国家	美国
语种	英语
英文摘要	This project will carry out new analyses of existing geophysical data with the complementary goals of advancing scientific understanding and improving upon future earthquake hazard forecasts. Subduction zones are where two tectonic plates collide and one sinks below the other. Subduction zones produce the largest earthquakes in the world, such as the magnitude 9.0 Tohoku earthquake of 2011 that caused widespread destruction in northern Japan. This project will focus on two subduction zone regions: Cascadia in the U.S. and Hikurangi in New Zealand. Onshore and offshore GPS data will be modeled to determine the amount of slip released as slow slip events, as steady creep, or where regions are locked and not slipping. Slow slip events refer to slip on a fault that is similar to what occurs during an earthquake, but occurs much more slowly and does not emit damaging seismic waves. Locked regions refer to areas of a fault in which friction prevents slip, allowing energy to build up for future release in an earthquake. In contrast to previous modeling work, this project will use realistic, three-dimensional elastic properties of the earth constrained by prior seismic studies. The products of this project will directly inform earthquake hazard forecasts for both the Cascadia and Hikurangi subduction zones, which have major cities nearby (Portland and Seattle in Cascadia; Wellington in Hikurangi). Important additional information will be obtained for an International Ocean Discovery Program project scheduled for the northern Hikurangi margin in 2018 that is targeting the slow slip region. The project will support and train an early career female scientist who will be mentored by a more established female scientist. The project also features public outreach through public talks in New Zealand and the U.S. and the incorporation of the results into lecture materials at two universities in the U.S. This project will generate new and improved catalogs of slow slip events and plate locking models for the Cascadia and Hikurangi (New Zealand) subduction zones. A Network Inversion Filter (NIF) technique will be used to process all available GPS data to identify slow slip events, and produce models of slip and slip-rate evolution over time. The NIF technique is based on a Kalman filter approach, which balances a physically reasonable but inaccurate model of steady slip with noisy data. Additionally, these NIF inversions will incorporate offshore ocean bottom pressure (OBP) data from the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip deployment during the mid-2014 to mid-2015 time period for the Hikurangi subduction zone. These OBP instruments recorded a large offshore slow slip event in late 2014. These models include, for the first time, realistic, three-dimensional earth structure and the effects topography and bathymetry. Long-term velocities of GPS stations will be modeled to obtain improved constraints on the plate interface locking region for each subduction zone. Plate locking indicates how much of the expected motion between tectonic plates is not occurring continuously at the boundary, and could therefore be released in earthquakes or slow slip events. GPS station velocities will be averaged in two ways: first only over times between slow slip events and second by averaging through slow slip events which will provide two locking models for each subduction zone. Products will include new realistic 3D locking models for the two regions, slow-slip event catalogs for both subduction zones and a full-slip budget with uncertainties for each subduction zone as a function of location over the time period of study.
来源学科分类	Geosciences - Ocean Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69285
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Laura Wallace.Collaborative Research: Improving models of interseismic locking and slow slip events in Cascadia and New Zealand.2016.