Bulk rheology of fault damage zone materials and its implication for interseismic fault mechanics

GSTDTAP

项目编号	1727661
	Bulk rheology of fault damage zone materials and its implication for interseismic fault mechanics
	Hiroki Sone
主持机构	University of Wisconsin-Madison
项目开始年	2017
	2017-08-01
项目结束日期	2020-07-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	338895(USD)
国家	美国
语种	英语
英文摘要	This project aims to better understand the tectonic loading process leading to devastating earthquakes in major plate boundaries. Advances in the past decade allows scientists to capture and simulate first-order characteristics of the earthquake cycle, but challenges remain in understanding the randomness and spatial variability of earthquake phenomena. This project specifically focuses on one of the complexities that may arise due to the fact that faults may not only slip at the very fault plane itself, but the surrounding damaged rock can also deform to accommodate plate motion. The project, carried out in collaboration with researchers from National Central University, Taiwan, involves characterization of damage zone samples from the Chelungpu fault, Taiwan, coupled with deformation experiments on those samples to explore the behavior of the damage zone under stress. Better understanding of such phenomena will illuminate what is still lacking in current earthquake fault models and lead to improved accuracy of seismic hazard analyses. The project would also advance desired societal outcomes through a strong research collaboration with Taiwanese scientists plus the opportunity for graduate students to exchange scientific ideas and cultural experiences essential to foster future generation of scientists who will work in an international collaborative environment. The objective of this study is to characterize the ductile deformational properties of fault damage zone rocks and to evaluate the importance of such behavior on fault mechanics. Most analytical and numerical fault mechanics models treat faults as a frictional interface embedded between elastic host rocks and does not take into account the peculiar characteristics of the damage zone surrounding the fault plane. However, damage zone rocks may undergo time-dependent ductile deformation even under crustal conditions, which has significant consequences on how shear stress develops on a fault during the interseismic period. The project focuses on the Chelungpu fault, Taiwan, where the high-quality core material was recovered from the 2004 International Continental Drilling Project. Detailed description of the fault damage zones in the Chelungpu fault system will be made with emphasis on fracture density, followed by creep experiments using damage zone samples to measure time-dependent strain behavior. Using lab-derived constitutive equations, deformation behavior of the damage zone under tectonic conditions will be evaluated. The ductile constitutive law will be combined with fault frictional properties in a numerical model to quantify the relative contribution of each domains, damage zone and fault core, to the total fault deformation during interseismic tectonic loading. Many geophysical observations suggest that permanent off-fault deformation may be occurring over long time scales (greater than a year). If, for instance, the partial-coupling of subduction interfaces inferred from geodetic studies is indeed due to steady off-fault deformation, the study may impact understanding of the stress accumulation process during interseismic tectonic loading.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71435
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Hiroki Sone.Bulk rheology of fault damage zone materials and its implication for interseismic fault mechanics.2017.