Collaborative Research: Continuing Support for the Basin and Range Geodetic Network (BARGEN): Active Tectonics of Diffuse Intracontinental Deformation

0135457 Davis该奖项为盆地和山脉大地测量网络(Bargen)的NSF资助部分提供了两年的持续支持。这一组成部分被称为北方盆地和山脉网络或“NBAR”，包括18个间隔约100公里的远程、连续监测的GPS站点，部署在LATH附近的东西向阵列中。40度。北缘，横跨北美板块广泛变形的西部边界。这些遗址安装于1996年和1997年，得益于钻探过的、固定在基岩中的有支撑的纪念碑，深度达10米，气候非常干燥。水平面上的每日位置估计显示，均方根散布在1-2毫米的水平上，时间序列分析和对大约4.5年数据的其他统计分析表明，水平速度在一个标准偏差下的误差小于0.2毫米/年。这一网络的继续运行迫在眉睫，因为它代表着美国国家科学基金会板块边界观测站(PBO)倡议的一个重要原型实验，该倡议提议在北美板块变形的西部边缘部署大约900个类似设计的新站点。NBAR场地计划最早在2004年用新仪器进行升级，前提是PBO得到资助(目前正作为国家科学基金会2003财政年度预算的一部分进行审议)。NBAR网站将形成PBO的100个网站“主干”网络的核心，以及北部盆地和山脉拟议的网站集群。在实施PBO之前和整个过程中，大地测量时间序列的连续性将为预测其最终能力和评估拟议的场地位置战略的优点提供最强有力的基础。NBAR站点另外两年的数据将在三个基本问题上产生重大影响，这些问题仍然存在争议：1)GPS时间序列受到低频噪声的污染程度；2)垂直速度的误差是否足够低，以提供具有地球物理意义的信号；以及3)是否期望大地测量确定的速度和地质确定的变形速率之间保持一致。在部署PBO之前，更多数据还将尽可能清楚地了解连续GPS的能力和局限性。*

0135457DavisThis 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.***