Collaborative Research: : Co-evolution and Dynamic Interplay of the San Jacinto and Southernmost San Andreas Fault Zones

PI请求资金用于分析加州南部圣哈辛托（SJFZ）和最南端圣安德烈亚斯（SAFZ）断层带之间断层相互作用的动力学。他们试图解决是否有一个下降的滑动率沿着的印第奥段的SAFZ有关的出生和持续成熟的SJFZ，和/或这两个断层带是否交替承担主导作用，在任何时间尺度上容纳相对板块运动在该地区。这些问题已被证明难以用任何一种地质/地球物理技术或数据类型来解决。 因此，他们将采用综合的，跨学科的方法来调查这些活动断层的演化，现今的行为和动力学。具体而言，PI的建议：-调查来自大地测量观测故障模型参数估计之间的权衡。他们将使用SCEC和SCIGN数据集以及逆弹性断层模型和更现实的粘弹性有限元正演模型来进行分辨率和协方差分析，以探索滑动速率、锁定深度、蠕变和地震周期对这些断层的影响之间的权衡。他们将（1）确定断层演化模型现今边界条件范围的边际置信界限，（2）确定大地测量覆盖范围的哪些改进（例如，PBO台站位置和台站密度）将是必要的，以便进一步缩小容许故障演化模型的类别。研究断层带几何形状和岩石圈流变学之间的相对重要性和反馈，采用3-D粘弹性有限元模拟方法进行数值模拟。他们的调查将包括评估SAFZ中约束弯曲的存在如何影响SJFZ和SAFZ之间的应变分配，东加州剪切带如何影响这种分配，以及SAFZ和SJFZ之间的断层带强度是否存在可解决的差异。用宇宙成因测年技术测定偏移冲积层的年龄，这种技术在十年前是不可能的，现在的精度是这样的。 的数量级增加不精确的偏移冲积扇年龄将允许PI的区分竞争模型的断层带演化超过10至100万年的时间尺度。这些新的宇宙成因测年测量将根据本建议免费进行。 相反，预计德国研究公司将提供资金来支付我们研究的这一部分的费用（DFG提案待定，Friedrich教授，P.I.）。构建一个模型的共同演变的SJFZ和SAFZ纳入aggregationof新的和现有的位移历史数据集在广泛的时间尺度为两个断层带，以及动力学的考虑。我们的综合方法将提供一个更全面的测试这些断层系统之间的断层滑动的依赖性比任何单独的技术可能提供自己的力量，我们的建议是，我们的多学科研究将协调的首要目标，测试竞争的假设，这个复杂的断层系统的演变。

The PI's request funds to analyze the dynamics of fault interaction between the San Jacinto (SJFZ)and southernmost San Andreas (SAFZ) fault zones in southern California. They seek to address whether there has been a decrease in the slip rate along the Indio segment of the SAFZ related to the birth and continued maturation of the SJFZ, and/or whether these two fault zones alternatively assume dominant roles in accommodating relative plate motion across the region over any time scales. These questions have proven difficult to address with any one geological/geophysical technique or data type. They will therefore employ an integrated, cross-disciplinary approach to investigate the evolution, present-day behavior,and dynamics of these active faults. Specifically, the PI's propose to:- Investigate trade-offs between fault model parameter estimates derived from geodetic observations. They will use the SCEC and SCIGN data sets together with inverse elastic faultmodels and more realistic visco-elastic finite element forward models to perform resolutionand covariance analyses to explore the trade-offs between slip rate, locking depth, creep, andseismic cycle effects on these faults. They will (1)determine marginal confidence bounds on therange of present-day boundary conditions on fault evolution models, and (2)determine whatimprovements in geodetic coverage (e.g.,PBO station locations and station density)will benecessary in order to further narrow the class of admissible fault evolution models.- Investigate the relative importance of, and feedbacks between, fault zone geometry, and lithospheric rheology by numerical simulations using a 3-D visco-elastic finite element modelingapproach. Their investigations will include an assessment of how the presence of the restrainingbend in the SAFZ affects partitioning of strain between the SJFZ and SAFZ, how the easternCalifornia shear zone affects this partitioning, and whether there are resolvable differences infault zone strength between the SAFZ and the SJFZ.- Determine the age of offset alluvial deposits using cosmogenic dating techniques which werenot available ten years ago, at the present-day precision. The order-of-magnitude increase inprecision of the offset alluvial fan ages will allow the PI's to discriminate between competing models for fault zone evolution over the 10 to 100 ka time scale. These new cosmogenic dating measurements will be made at no additional cost under this proposal. Rather, funds to cover thecosts of this component of our research are anticipated from Deutsche Forschungsgesellschaft(DFG proposal pending, Prof. Friedrich, P.I.).- Construct a model for the co-evolution of the SJFZ and SAFZ incorporating an aggregationof new and existing displacement history data sets across a broad range of time scales forboth fault zones, as well as dynamical considerations. Our integrated approach will providea more comprehensive test of fault slip dependence between these fault systems than anyindividual technique could possibly provide on its own.The strength of our proposal is that our multidisciplinary research will be coordinated by theover-riding goal of testing competing hypotheses for the evolution of this complex fault system.