Collaborative Research: Continuing support for the Basin and Range Geodetic Network (BARGEN): Active tectonics of diffuse intracontinental deformation

该合同为美国国家科学基金会资助的盆地和山脉大地测量网（BARGEN）的组成部分提供了两年的持续支持。该组件被称为北部盆地和山脉网络或“NBAR”，包括18个远程、连续监测的GPS站点，间隔约100公里，在晚些时候以东西阵列部署。北纬40度，横跨扩散变形的北美板块西部边界。这些遗址分别于1996年和1997年建成，得益于钻探和支撑的纪念碑，这些纪念碑锚定在10米深的基岩上，气候非常干燥。水平的日位置估计值在1-2毫米水平上显示均方根散点，对大约4.5年数据的时间序列分析和其他统计分析表明，在一个标准差下，水平速度的误差小于0.2毫米/年。该网络的继续运行是迫切需要的，因为它代表了NSF板块边界观测站（PBO）倡议的重要原型实验，该倡议建议在不断变形的北美板块西缘部署大约900个类似设计的新站点。如果PBO得到资助（目前正在考虑作为NSF 2003财年预算的一部分），NBAR站点计划最早在2004年用新仪器进行升级。NBAR站点将构成PBO的100个站点“骨干”网络的核心，以及北部盆地和山脉的拟议站点集群。在实施PBO之前和实施过程中，大地测量时间序列的连续性将为预测其最终能力和评估建议的地点战略的优点提供最强有力的基础。另外两年来自NBAR站点的数据将对三个基本问题（但仍有争议）产生重大影响：1)GPS时间序列受低频噪声污染的程度；2)垂直速度误差是否足够小，能够提供有物理意义的信号；3)是否期望大地测量确定的速度与地质确定的变形速率一致。在部署PBO之前，额外的数据还将提供对连续GPS的能力和局限性的尽可能清晰的了解

0136102WernickeThis award provides two years of continued support for the NSF-funded component of the Basin and Range Geodetic Network (BARGEN). This component, known as the Northern Basin and Range network or "NBAR," includes 18 remote, continuously monitored GPS sites with ~100 km spacing, deployed in an east-west array near lat. 40 deg. N, spanning the diffusely deforming western boundary of the North American plate. Installed in 1996 and 1997, these sites benefit from drilled, braced monuments anchored in bedrock to a depth of 10m and a very dry climate. Daily position estimates in the horizontal exhibit root-mean-square scatter at the 1-2 mm level, and time series analysis and other statistical analyses of some 4.5 years of data indicate errors in horizontal velocity of less than 0.2 mm/yr at one standard deviation. Continued operation of this network is urgent, because it represents an important prototype experiment for NSF's Plate Boundary Observatory (PBO) initiative, which proposes the deployment of some 900 new sites of similar design across the deforming western margin of the North American plate. The NBAR sites are scheduled to be upgraded with new instruments as early as 2004 provided PBO is funded (now under consideration as part of NSF's FY 2003 budget). The NBAR sites will form the nucleus of PBO's 100-site "backbone" network and of proposed site clusters in the northern Basin and Range. Continuity of geodetic time series up to and through PBO implementation will provide the strongest possible basis for predicting its ultimate capability, and for assessing the merits of proposed strategies for site locations. An additional two years of data from the NBAR sites will bear significantly on three fundamental - and still controversial - questions: 1) the degree to which GPS time series are contaminated by low-frequency noise; 2) whether errors in vertical velocities will be low enough to provide geophysically meaningful signal; and 3) whether to expect agreement between geodetically determined velocities and geologically determined deformation rates. Additional data will also provide the clearest possible understanding of the capabilities and limitations of continuous GPS prior to PBO deployment.***