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

在过去的十年里，美国的普雷斯科特构造和地震研究经历了一场悄无声息的革命，人们认识到慢动作断层事件既可以触发，也可以由常规地震触发。瞬变运动现在基本上已经在所有的构造环境中被发现，而对这种事件的探测和分析是地球望远镜计划的首要科学目标。由于这一点以及许多其他只能用长时间大地测量时间序列才能回答的基本构造问题，最初的1400个站的地球望远镜板块边界观测站(PBO)网络的设计利用了432个现有的连续GPS站，这些站的测量数据可以追溯到十年前。这些空间站不可替代的记录历史正在通过提供尽可能高的分辨率来加速EarthScope科学回归。该分辨率将用于检测和了解瞬变，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络的子集的运营、维护和硬件升级，直到它们被纳入PBO。来自这些站点的不间断数据流将在EarthScope的预期寿命内有效地将PBO的时间序列长度增加一倍，并首次在美国创建了一个基于GPS的单一大地测量网络。其他现有站点仍在非国家科学基金会来源(如美国地质勘探局)的支持下运营，EarthScope继续受益于它们的持续运营。基于与地球范围科学目标、地理分布和数据质量的相关性，在现有的432个站中，有209个被选为建立多国办事处的核心。在以前的资助下，开始将这些站点转换为与PBO兼容的运行模式，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个站点将完全并入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。在建设阶段结束后，这些站的运营资金已列入PBO的计划预算，PBO将于2008年开始运营阶段。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，缓慢的断层活动是否普遍减缓了地震的成核。慢震的存在将影响地震危险性的估计，因为现在已知这些瞬变在一些地区‘吸收’了总滑移的很大一部分，并在其他地区触发了地震。来自这些电视台的数据服务于更多的受众，而不仅仅是为数不多的让它们继续运行的人。该项目目前正在收集数据，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、教育工作者和课程开发专业人员组成的团队正在开发教育单元，并通过区域和国家讲习班进行传播。一个互动网站为K-16课堂提供了构造研究的最新进展。

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.