气候变化领域集成服务门户(CCPortal): Seasonal and Long-Term Groundwater Unloading in the Central Valley Modifies Crustal Stress

CCPortal

DOI	10.1029/2019JB018490
	Seasonal and Long-Term Groundwater Unloading in the Central Valley Modifies Crustal Stress
	Carlson G.; Shirzaei M.; Werth S.; Zhai G.; Ojha C.
发表日期	2020
ISSN	21699313
卷号	125 期号:1
英文摘要	Changes in terrestrial water content cause elastic deformation of the Earth's crust. This deformation is thought to play a role in modulating crustal stress and seismicity in regions where large water storage fluctuations occur. Groundwater is an important component of total water storage change in California, helping to drive annual water storage fluctuations and loss during periods of drought. Here we use direct estimates of groundwater volume loss during the 2007–2010 drought in California's Central Valley obtained from high resolution Interferometric Synthetic Aperture Radar-based vertical land motion data to investigate the effect of groundwater volume change on the evolution of the stress field. We show that GPS-derived elastic load models may not capture the contribution of groundwater to terrestrial water loading, resulting in an underestimation of nontectonic crustal stress change. We find that groundwater unloading during the drought causes Coulomb stress change of up to 5.5 kPa and seasonal fluctuations of up to 2.6 kPa at seismogenic depth. We find that faults near the Valley show the largest stress change and the San Andreas fault experiences only ~40 Pa of Coulomb stress change over the course of a year from groundwater storage change. Annual Coulomb stress change peaks dominantly in the fall, when the groundwater level is low; however, some faults experience peak stress in the spring when groundwater levels are higher. Additionally, we find that periods of increased stress correlate with higher than average seismic moment release but are not correlated with an increase in the number of earthquakes. This indicates groundwater loading likely contributes to nontectonic loading of faults, especially near the Valley edge, but is not a dominant factor in modulation of seismicity in California because the amplitude of stress change declines rapidly with distance from the Valley. By carefully quantifying and spatially locating groundwater fluctuations, we will improve our understanding of what drives nontectonic stress and forces that modulate seismicity in California. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	CA; Central Valley; Earthquake modulation; groundwater; nontectonic stress; seasonal loading
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/188041
作者单位	School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States; School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, United States; Department of Earth and Planetary Science, University of California, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Carlson G.,Shirzaei M.,Werth S.,et al. Seasonal and Long-Term Groundwater Unloading in the Central Valley Modifies Crustal Stress[J],2020,125(1).
APA	Carlson G.,Shirzaei M.,Werth S.,Zhai G.,&Ojha C..(2020).Seasonal and Long-Term Groundwater Unloading in the Central Valley Modifies Crustal Stress.Journal of Geophysical Research: Solid Earth,125(1).
MLA	Carlson G.,et al."Seasonal and Long-Term Groundwater Unloading in the Central Valley Modifies Crustal Stress".Journal of Geophysical Research: Solid Earth 125.1(2020).