Collaborative Research: Rio Grande Rift II - Kinematics and Dynamics of Continental Deformation in Low Strain-Rate Environments

里奥格兰德裂谷全球定位系统(GPS)网络由2006年和2007年安装在科罗拉多州和新墨西哥州的25个GPS纪念碑组成。初步结果结合其他连续的GPS数据表明，跨越里奥格兰德裂谷和邻近地形省的变形模式是广泛分布的，并不集中在裂谷的表面表现上。鉴于这是一个低应变率的环境，需要较长的观测时间，正在将里奥格兰德裂谷全球定位系统网络转移到联安办事处进行长期观测。除了利用里奥格兰德裂谷GPS数据估计统一的场地速度外，还正在确定应变分量和刚体旋转，以更好地描述分布变形的性质。正在评估形变的垂直部分，较长的时间序列开始能够解决这一问题。USArrow可移动阵列地震数据正被用于研究里奥格兰德裂谷及其周围地区的地震活动和震源参数。改进的地震位置将使用区域速度模型和先进的定位算法来确定。全波形矩张量反演被用来确定震源参数。特别注意确定震源深度、应力降和地震滑动向量。项目更广泛的影响包括两名研究生的教育和参与、教员参与SAGE(应用地球物理暑期体验)、评估导论地质学课程的全球定位系统课堂练习，以及将5个全球定位系统纪念碑改建为广泛大地测量界的永久观测站。

The Rio Grande Rift Global Positioning System (GPS) network consists of 25 GPS monuments installed throughout Colorado and New Mexico in 2006 and 2007. Initial results combined with other continuous GPS data suggest that the deformation pattern across the Rio Grande Rift and adjacent physiographic provinces is broadly distributed and is not focused on the surficial expression of the rift. Given that this is a low strain-rate environment, long observing times are needed, and the Rio Grande Rift GPS network is being transferred to UNAVCO for longer-term observations. In addition to estimating uniform site velocities with the Rio Grande Rift GPS data, strain components and rigid-body rotations are being determined to better characterize the nature of the distributed deformation. The vertical component of deformation is being assessed, which the longer time-series are beginning to be able to resolve. USArray Transportable Array seismic data are being used to study seismicity and earthquake source parameters along the Rio Grande Rift and in surrounding regions. Improved earthquake locations will be determined using regional velocity models and advanced location algorithms. Full waveform moment tensor inversion is being used to determine earthquake source parameters. Special care is going into determining hypocenter depth, stress drop, and earthquake slip vectors. Project broader impacts include education and involvement of two graduate students, participation by faculty in SAGE (Summer of Applied Geophysical Experience), assessment of a GPS in-class exercise for introductory geology courses, and conversion of 5 GPS monuments to permanent stations for the broad geodetic community.