Collaborative Research: Testing Tectonic Geodesy from Fault Slip Rates Across the Eastern California Shear Zone

东加州剪切带是板块边界断层系统的一个有趣的例子，在那里已知的断层速率加起来可能不等于应变累积的大地测量速率。这项研究测试的假设，地质和大地应变率必须以某种方式同意整个东加州剪切带收集新的长期滑动速率数据从一个定义明确，暴露良好，构造简单的横断面活动断层横跨中部莫哈韦沙漠。通过有针对性地采集高分辨率机载激光条带测绘测高数据，进行实地地貌和地质测绘，将记录六个右侧走滑断层中每一个断层上的上新世-第四纪熔岩流和冲积扇的偏移。选定的偏移标志物将用40 Ar/39 Ar、宇宙成因10 Be或宇宙成因3 He测年，以测量10^5至10^6年时间尺度的地壳形变速率，平均几个地震周期。 如果地质学确实通过一个或多个断层上的显著滑动速率来解释大地应变率，则构造大地测量学的预测能力就得到了证明。另外，如果长期地质应变速率明显低于大地测量速率，这似乎得到了现有古地震数据的支持，那么全系统范围内的瞬态加载过程必须对东加州剪切带现今的高应变积累负责。

The Eastern California Shear zone is an intriguing example of a plate boundary fault system where the known rates of faulting may not add up to the geodetic rate of strain accumulation. This research tests the hypothesis that geologic and geodetic strain rates must somehow agree across the Eastern California Shear zone by gathering new long-term slip rate data from a well-defined, well-exposed, and tectonically simple transect of active faulting across the central Mojave Desert. Field geomorphic and geologic mapping, augmented by targeted acquisition of high-resolution airborne laser swath mapping altimetry data, will document offset Plio-Quaternary lava flows and alluvial fans across each of six right-lateral strike-slip faults. Selected offset markers will be dated with 40Ar/39Ar, cosmogenic 10Be or cosmogenic 3He to measure crustal deformation rates at 10^5 to 10^6 year time scales that average several earthquake cycles. If the geology does account for the geodetic strain rate through significant slip rates on one or more faults, the predictive capability of tectonic geodesy is demonstrated. Alternatively, if the long-term geologic strain rate is significantly slower than the geodetic rate, as seems to be supported by existing paleoseismic data, then a system-wide transient loading process must be responsible for the high present-day strain accumulation across the Eastern California Shear zone.