Leveraged acquisition of a Seattle fault GPS network: Four dimensional constraint on seismic and aseismic strain accumlation and release in the urbanized Puget Lowlands

[0216626]米勒利用全球定位系统（GPS）大地测量法进行连续观测，可以高精度地确定水平和垂直变形率及其随时间和空间的变化。该项目建立在去年太平洋西北大地测量阵列（PANGA）数据取得的惊人进展的基础上。PANGA的科学家们将与普吉特海湾的测量社区合作，安装一个连续的GPS网络，该网络经过优化设计，可以确定西雅图断层带的运动学和锁定，西雅图断层带是北美板块内的一个主要断层。此外，该网络对最近在卡斯卡迪亚板块界面过渡带发现的慢震或无震周期性复发提供了重要的新约束。这两项研究都对描述板块相互作用的地球动力学具有重要意义，它们也对量化位于城市化的普吉特低地中心的地壳断层的地震应变能积累具有更广泛的影响。这个网络将为板块边界断层上地震和地震应变释放机制之间的相对平衡增加新的限制，已知板块边界断层以大约500年的频率产生大地震（大约9级）。最后，该项目将促进区域专业和学术界之间的新生合作。普吉特海湾测量社区已经成立了一个联盟，以支持新的GPS技术在普吉特低地城市化的协调。这个由市、县、州机构和工程公司合作的项目致力于安装一个名为Puget参考系统实用程序（PRSU）的“虚拟参考系统”GPS网络，可以提供厘米级的实时定位。幸运的是，这个网络对于上面概述的地震和地球动力学研究是最佳的，需要注意的是，固体地球变形社区有最高的纪念碑标准，以便GPS天线跟踪真实的地球运动，而不是土壤、地下水或人造结构的影响。普吉特低地对稳定的纪念碑设计提出了最大的一级挑战：厚厚的土壤层，西雅图断层下壁的深沉积盆地以及最后一次冰川退缩留下的碎片地幔需要使用深锚钻孔支撑纪念碑。因此，这样的纪念对于进行这里提出的问题所要求的高精度的有意义的地球物理观测是至关重要的。该项目资助大地测量质量纪念碑，以便以高度杠杆的方式利用PRSU GPS网络进行固体地球变形研究。＊＊＊

0216626MillerContinuous observations using Global Positioning System (GPS) geodesy yield high-precision determination of horizontal and vertical deformation rates and their variation in time and space. This project builds on the stunning advances that data from the regional Pacific Northwest Geodetic Array (PANGA) has yielded over the last year. In partnership with the surveying community in Puget Sound, PANGA scientists will install a continuous GPS network that is optimally designed to determine the kinematics and locking of the Seattle fault zone, a major fault within the North America plate. In addition, this network provides important new constraints on the periodic recurrence of slow or silent earthquakes, which have been recently discovered along the transition zone of the Cascadia plate interface. Both studies have fundamental importance to characterizing the geodynamics of plate interaction, they also have broader impacts on quantifying seismic strain energy accumulation on a crustal fault that lies in the heart of the urbanized Puget Lowlands. This network will add new constraints to the relative balance between seismic and aseismic strain release mechanisms on the plate boundary fault that is known to generate great earthquakes (approximately magnitude 9) at frequencies of about 500 years. Finally, this project will foster the nascent collaboration between regional professional and academic communities.The Puget Sound surveying community has formed a consortium to support coordination of new GPS technology to the urbanized Puget Lowlands. This collaboration of cities, counties, state agencies, and engineering firms is committed to installing a "virtual reference system" GPS network known as the Puget Reference System Utility (PRSU) that can provide cm-level positioning in real time. Fortuitously, this network is optimal for the earthquake and geodynamics studies outlined above, with the caveat that the solid earth deformation community has the highest standards for monumentation in order that GPS antennas track real earth motion rather than the effects of soil, gourndwater or man-made structures. The Puget Lowlands present the greatest first-order challenges to stable monument design: thick soil horizons, deep sedimentary basins in the foot wall of the Seattle fault and a mantle of debris left behind in the last glacial retreat require use of the deeply anchored drilled braced monument. Such monumentation is thus critical to making geophysically meaningful observations of great precision required by the problems posed here. This project funds geodetic quality monuments in order to leverage the PRSU GPS network for solid earth deformation studies in a highly leveraged fashion. ***