Collaborative Research: Self-Consistent Kinematics and Dynamics of the U.S

研究人员建议使用最新的GPS/VLBI/SLR观测、第四纪断层滑动速率、大地水准面、地壳厚度变化和地形数据来量化北美西部的应变速率张量场和垂直平均偏应力张量场。到目前为止的结果表明，重力势能(GPE)差异控制着加州海岸观测到的大的断层-正常挤压以及瓦萨奇山脉的伸展。盆地和山脉的变形部分是由重力势能差异驱动的，但那里的伸展方向受到板块相互作用应力的强烈影响。分析将扩展到调查北至阿拉斯加的压力状态，并向南包括里维拉三重交界处。分析的领域将包括GPE差异对中大西洋海脊的影响。耦合分析将利用GPS、VLBI、SLR和第四纪断层滑移率的观测来研究自洽运动学。提出的联合运动学和动力学模型很重要，因为它提供了对大地测量(GPS、VLBI、SLR)、岩石圈应变率和岩石圈应力之间关系的全面理解。动力学的精细模型将使用正演建模方法进行研究，速度边界条件由运动学建模确定。他们还将调查基础牵引力在影响动力学方面的可能作用。这项工作应为加强拟议的板块边界观测站和美国阵列倡议的规划和实施提供重要的投入。

EAR-0001541Hamburger, Michael W.The investigators propose to use recent GPS/VLBI/SLR observations, Quaternary fault slip rates, the geoid, crustal thickness variations, and topography data to quantify both the strain rate tensor field and the vertically averaged deviatoric stress tensor field within western North America. Results to date indicate that gravitational potential energy (GPE) differences control the large fault-normal compression observed along the California coast as well as the extension at the Wasatch Range. Deformation in the Basin and Range is driven, in part, by gravitational potential energy differences but the extension directions there are strongly modified by plate interaction stresses. The analysis will be extended to investigate the state of stress north to Alaska, and south to include the Rivera Triple Junction. The area of analysis will include the effects of GPE differences out to the Mid-Atlantic Ridge. A coupled analysis will investigate the self-consistent kinematics using observations from GPS, VLBI, SLR, and Quaternary fault slip rates. The proposed joint kinematic and dynamic modeling is important because it provides a comprehensive understanding of the relationship between geodetic observations (GPS, VLBI, SLR), lithospheric strain rates, and lithospheric stress. Refined models of the dynamics will be investigated using forward modeling methods with velocity boundary conditions determined from the kinematic modeling. They will also investigate the possible role of basal tractions in affecting the dynamics. This work should provide important input to enhance the planning and implementation of the proposed Plate Boundary Observatory and USArray initiatives.