Collaborative Research: Geodetic Constraints on the Kinematics of the Colorado Plateau and its Western and Southern Margin

合作研究：科罗拉多高原及其西部和南部边缘运动的大地测量约束美国西南部的科罗拉多高原在太平洋-北美板块边界带的地质演化中起着重要作用。与美国西部其他大部分地区不同，科罗拉多高原在其地质历史的大部分时间里基本保持完整。 事实上，该地区几乎没有活跃的地震断层。然而，地震确实发生在科罗拉多高原内，一些非常大的地震发生在亚利桑那州南部和墨西哥北方。这个项目使用精确的GPS测量来确定科罗拉多高原的地壳如何相对于稳定的北美移动。水平速度的解释告诉调查人员该地区是否作为一个连贯的块体移动或内部变形。在前一种情况下，预计很少有地震活动，而在后一种情况下，该地区的地震危险可能比目前认为的要高。比较GPS数据和地震数据所暗示的变形，以评估地震活动是否与本项目中测量的变形有关，或者它们是否是由于其他过程，如重力塌陷。为了进行测量，在亚利桑那州、犹他州南部和内华达州东南部安装了33个新的GPS站。这些观测站补充并加强了NSF EarthScope板块边界观测站长期运行的连续GPS观测站。需要额外的台站来创建约束良好的模型，以描述该地区的现今构造。有了一个约束良好的变形模型，就可以研究科罗拉多高原运动和变形的起源。考虑的一些模型包括高原的刚性运动导致格兰德河裂谷的开放，地壳伸展侵入高原由于地幔过程的演变，以及太平洋板块运动对南部盆地和山脉变形的影响。调查人员提供教育材料，告知公园该地区的活动构造和项目的目的。这些外展活动的目的是教育公园的游客，他们所处的地质仙境正在积极变化，由于地质过程。测量为期四年，该项目涉及培训一名研究生。该项目的结果可能用于重新评估该地区的地震危险性？的城市中心。

Collaborative Research: Geodetic Constraints on the Kinematics of the Colorado Plateau and its Western and Southern MarginThe Colorado Plateau, southwestern United States, has played an important role in the geologic evolution of the Pacific-North America plate boundary zone. Unlike most other parts of the western U.S., the Colorado Plateau has remained largely intact during most of its geologic history. Indeed, the area shows little to none active earthquake faults. However, earthquakes do happen within the Colorado Plateau, and some very large ones have occurred in southern Arizona and northern Mexico.This project uses precise GPS measurements to establish how the crust of the Colorado Plateau moves relative to stable North America. Interpretation of the horizontal velocities tells the investigators whether the area moves as a coherent block or is internally deforming. In case of the former little earthquake activity is expected, and in case of the latter the seismic hazard in the region may be higher than currently thought. The deformation implied by the GPS data and earthquake data is compared in order to assess whether the earthquake activity can be related to the deformation measured in this project or whether they are due to other processes, such as gravitational collapse. To perform the measurements, 33 new GPS stations are installed in Arizona, southern Utah and southeastern Nevada. These stations complement and densify the long-running continuous GPS stations of NSF EarthScope's Plate Boundary Observatory. The additional stations are needed to create well-constrained models to describe the region's present-day tectonics. With a well-constrained model of the deformation can the origin of the motion and deformation of the Colorado Plateau be investigated. Some of the models that are considered include a rigid motion of the plateau causing opening of the Rio Grande Rift, crustal extension encroaching into the plateau due to evolving mantle processes, and the effect of Pacific plate motion on the deformation of the southern Basin and Range.Many of the new GPS stations are installed in National Parks and Monuments, as well as in State Parks. The investigators provide educational material to inform the parks on the active tectonics of the region and the aim of the project. The goal of these outreach activities is to educate the parks' visitors that the geologic wonderland they are in is actively changing due to geologic processes. Measurements are made for four years and the project involves training of a graduate student. The outcome of this project may be used in a reassessment of the seismic hazard in the region?s urban centers.