PBO Nucleus: Support for an Integrated Existing Geodetic Network in the Western U.S.

在过去的十年里，美国的构造和地震研究经历了一场悄无声息的革命，这是因为人们认识到，慢动作的断层活动既可以触发常规地震，也可以被常规地震触发。现在，在基本上所有的构造环境中都发现了瞬态运动，对此类事件的检测和分析是地球范围项目的一级科学目标。由于这一点以及许多其他基本的构造问题，这些问题只能用长时间的大地测量时间序列来回答，最初的1400站地球范围板块边界观测站（PBO）网络被设计成利用432个现有的连续GPS站，这些站的测量可以追溯到十多年前。这些站点无可替代的记录历史通过提供尽可能高的分辨率，加速了地球观测的科学回报。该分辨率将用于检测和理解瞬态，确定三维速度场（特别是垂直运动），并通过了解GPS固有的复杂噪声源来提高测量精度。PBO核项目支持美国西部六个大地测量网的一个子集的操作、维护和硬件升级，直到它们被PBO纳入。在EarthScope的预期寿命期内，这些站点的不间断数据流将有效地使PBO的时间序列长度增加一倍，并首次在美国建立了一个单一的基于gps的大地测量网络。其他现有站点在非nsf来源（例如美国地质勘探局）的支持下继续运行，而EarthScope继续受益于它们的继续运营。基于与EarthScope科学目标的相关性、地理分布和数据质量，在现有的432个台站中选择了209个作为建立PBO的核心。在之前的资助下，这些台站开始转换为与PBO兼容的操作模式，因此数据现在直接流向PBO档案和处理中心，同时维护、操作和元数据要求继续升级到PBO标准。在该项目结束时，所有209个站点将完全纳入PBO，满足新PBO建设的所有标准，包括数据通信和土地使用许可证。在建设阶段结束和PBO于2008年开始运营阶段后，这些站的运营资金已列入PBO的计划预算。研究界才刚刚开始了解瞬时蠕变的普遍影响，其社会后果在很大程度上仍未被探索。例如，一个悬而未决的问题是，缓慢的断层是否普遍地缓和了地震成核。缓震的存在将影响地震灾害的估计，因为现在已知这些瞬变会“吸收”某些地区总滑动的重要组成部分，并在其他地区引发地震。这些电台的数据服务于更多的受众，而不仅仅是维持它们运营的少数人。这个项目现在正在收集数据，这些数据将被下一代固体地球研究人员使用至少20年。一个由研究人员、教育工作者和课程发展专业人员组成的小组正在开发教育模块，并通过区域和国家讲习班进行传播。一个互动网站为K-16教室提供构造学研究的最新进展。

0453975PrescottTectonic and earthquake research in the US has experienced a quiet revolution over the last decade precipitated by the recognition that slow-motion faulting events can both trigger and be triggered by regular earthquakes. Transient motion has now been found in essentially all tectonic environments, and the detection and analysis of such events is the first-order science target of the EarthScope Project. Because of this and a host of other fundamental tectonics questions that can be answered only with long-duration geodetic time series, the incipient 1400-station EarthScope Plate Boundary Observatory (PBO) network has been designed to leverage 432 existing continuous GPS stations whose measurements extend back over a decade. The irreplaceable recording history of these stations is accelerating EarthScope scientific return by providing the highest possible resolution. This resolution will be used to detect and understand transients, to determine the three-dimensional velocity field (particularly vertical motion), and to improve measurement precision by understanding the complex noise sources inherent in GPS.The PBO Nucleus project supports the operation, maintenance and hardware upgrades of a subset of the six western U.S. geodetic networks until they are subsumed by PBO. Uninterrupted data flow from these stations will effectively double the time-series length of PBO over the expected life of EarthScope, and has created, for the first time, a single GPS-based geodetic network in the US. The other existing sites remain in operation under support from non-NSF sources (e.g. the USGS), and EarthScope continues to benefit from their continued operation. On the grounds of relevance to EarthScope science goals, geographic distribution and data quality, 209 of the 432 existing stations were selected as the nucleus upon which to build PBO. Conversion of these stations to a PBO-compatible mode of operation was begun under previous funding, and as a result data now flow directly to PBO archives and processing centers while maintenance, operations, and meta-data requirements are continue to be upgraded to PBO standards. At the end of this project all 209 stations will be fully incorporated into PBO, meeting all standards for new PBO construction including data communications and land use permits. Funds for operation of these stations have been included in planned budgets for PBO after the construction phase ends and PBO begins an operational phase in 2008.The research community has only begun to understand the pervasive effects of transient creep, and its societal consequences remained largely unexplored. For example, one open question is whether slow faulting pervasively moderates earthquake nucleation. The existence of slow earthquakes will impact seismic hazards estimation, since these transients are now known to 'absorb' a significant component of total slip in some regions and trigger earthquakes in others. The data from these stations serve a much larger audience than just the few people who work to keep them operating. This project is now collecting the data that will be used by the next generation of solid-earth researchers for at least two decades. Educational modules are being developed by a team of researchers, educators, and curriculum development professionals, and are being disseminated through regional and national workshops. An interactive website provides the newest developments in tectonics research to K-16 classrooms.