Collaborative Research: Multi-scale validation of earthquake source parameters to resolve any spatial, temporal or magnitude-dependent variability at Parkfield, CA

GSTDTAP

项目编号	1547071
	Collaborative Research: Multi-scale validation of earthquake source parameters to resolve any spatial, temporal or magnitude-dependent variability at Parkfield, CA
	Xiaowei Chen
主持机构	University of Oklahoma Norman Campus
项目开始年	2016
	2016-03-15
项目结束日期	2019-02-28
资助机构	US-NSF
项目类别	Standard Grant
项目经费	224262(USD)
国家	美国
语种	英语
英文摘要	Improved estimates of seismic hazard are necessary to reduce the major human and financial losses suffered in earthquakes every year. The stress released during an earthquake (called the stress drop) controls the ground accelerations produced by the earthquake waves, and hence the damage potential. The stress drop is also fundamental to understanding and modeling the physics of the earthquake source, because it defines the energy budget. It is important to know whether stress drop varies from region to region, and with earthquake magnitude. This is because earthquake parameters and ground shaking measurements in regions of high seismicity are often used to estimate hazard in other regions that may have lower historic seismicity rate, for example regions with induced seismicity. However it is currently unknown how much stress drop really varies between earthquakes. The observed variability ranges over a factor of 100 to 1000, which poses significant challenges in interpreting stress drop results. It is often not clear how much of the variability comes from measurement uncertainties, and how much represents real regional variations in fault properties. The investigators will focus on the section of the San Andreas Fault near Parkfield, in central California, where there is a high rate of earthquakes, including distinct sequences of small repeating earthquakes, and the fault also creeps slowly. It is one of the best-instrumented sections of fault in the world. The award will aid the development of a new geophysics group at the University of Oklahoma by supporting a beginning-career female PI, and a graduate student. The student will have the opportunity to be an active participant in the research communities in both Boston and Oklahoma. The research activities will help to establish earthquake research in Oklahoma, a state with increased awareness of earthquake hazard due to dramatic increase in seismicity, and will be integrated into classroom activities. The large number of earthquakes and the long-term dense networks of seismometers make this region a natural laboratory for understanding earthquake source physics. The multiple-scale dense observational networks provide on-scale recordings for a wide magnitude range; the existing detailed research provides a well-defined context in which to interpret the results. The Investigators propose to apply multi-scale (both large- and small-scale) analysis methods to the dense dataset of earthquake waveforms aimed at resolving the continuing controversy regarding earthquake scaling and variability. The investigators will calculate the stress release for a large number of earthquakes in multiple ways, using different subsets of the data. The work will focus on three distinct questions: (1) Is the apparent scaling of stress drop an artifact of poor data with limited bandwidth, limited magnitude range, and inadequate correction for site and propagation effects? (2) Do the stress drops of repeating earthquakes at Parkfield change with time as a result of the change in strain rate from the 2004 M6 Parkfield earthquake? (3) What data quality and analysis requirements are needed to confirm that spatial and temporal variations observed here and in future studies are real? The proposed research will increase understanding of the earthquake source process, both at Parkfield, and beyond. The methods developed, and the greater understanding of their limitations and constraints should enable a higher resolution of earthquake source parameters, and hence seismic hazard maps, worldwide.
来源学科分类	Geosciences - Earth Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69248
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Xiaowei Chen.Collaborative Research: Multi-scale validation of earthquake source parameters to resolve any spatial, temporal or magnitude-dependent variability at Parkfield, CA.2016.