Hybrid Measurements of Crustal Deformation in Guerrero, Mexico

最近的改进，我们的理解的物理和流变断层滑动表明，预测模型的断层位移可能在不久的将来。 这种模型需要大地测量学和地震学的观测约束，理想情况下，观测应包括大于地震周期的时间尺度。 科罗拉多大学与墨西哥国立自治大学合作，正在利用墨西哥格雷罗州的数据开发一个巨型逆冲断层滑动的综合模型。 研究区域包括可可-北美板块边界约100公里的一段，地震滑动亏损超过5米。 大地测量数据表明，显着的瞬变，最近发生在格雷罗俯冲界面上的滑动。 这就提出了一个基本问题：格雷罗的地震滑动缺陷（或“地震空区”）是否代表了板块边界应变的一个非常成熟的积累？ 或者，格雷罗的俯冲大规模逆冲断层是否在抗震方面减轻了大部分应变积累？换句话说，格雷罗的瞬时运动是否会转化为更高的地震危险，或更低的危险，比其他巨型推力？ 这个问题正在通过数据收集和建模相结合来解决。 目前正在用CU和墨西哥国立自治大学操作的全球定位系统接收器对格雷罗缺口进行持续监测。 这些全球定位系统数据被结合起来，每天估计位置，并用作模型的输入。 全球定位系统接收器也以较高的频率（5赫兹）工作，以便在地震期间能够估计较高频率的位置，并与也在格雷罗收集的地震数据相结合。

Recent improvements in our understanding of the physics and rheology of fault slip suggest that predictive modeling of fault displacement may be possible in the near future. Such models require observational constraints from both geodesy and seismology, and ideally the observations should encompass time scales greater than that of the earthquake cycle. Working collaboratively with UNAM (National Autonomous University of Mexico), the University of Colorado is developing an integrated model of megathrust fault slip, using data from the state of Guerrero, Mexico. The study area encompasses a ~100 km segment of the Cocos-North America plate boundary with more than 5 m of seismic slip deficit. The geodetic data suggest that significant transient, aseismic slip recently occurred on the Guerrero subduction interface. This poses a fundamental question: does the seismic slip deficit (or "seismic gap") in Guerrero represent a very mature accumulation of plate boundary strain? Or, does the subduction megathrust in Guerrero relieve most of its strain accumulation aseismically? In other words, does transient motion in Guerrero translate to a higher seismic hazard, or a lower hazard, than on other megathrusts? This question is being addressed via a combination of data collection and modeling. The Guerrero gap is being monitored continuously with GPS receivers operated by CU and UNAM. These GPS data are combined to estimate positions on a daily basis and are used as input to the models. The GPS receivers are also being operated at higher rates, 5 Hz, so that higher rate positions can be estimated during earthquakes and combined with seismic data also being collected in Guerrero.