Collaborative Research: New Heat Flow Values at PBO Borehole Strain Meter Sites: Implications for Deformation

EarthScope的首要目标是阐明北美大陆的动态和演变。为了实现这一目标，重点研究大陆地震结构、岩石圈的强度和变形模式、应力和应变的模式以及岩石圈在地震期间对激发的反应方式都是一个高度优先的问题。连接这些地球观测目标的共同因素是岩石圈的热状态。热流观测为岩石圈热状态提供了最强的观测约束。考虑到地下热条件与控制岩石圈变形时空变化的物理过程的相关性，更深入地了解地下热状态将对EarthScope的总体目标，特别是板块边界观测站（PBO）实验的总体目标做出重大贡献。我们将合作（俄勒冈州立大学、犹他大学和美国地质调查局）对美国西部太平洋和北美板块之间的活动板块边界进行热调查。热测量将在目前计划钻探的PBO井眼中收集。现场部分包括热测井和岩石热物性测定。在钻井结束和应变仪安装开始之间进行井眼测井，以免影响PBO作业。岩石的热物理性质将使用现代实验室技术进行测量。出于后勤和经济原因，我们将此建议限制在加利福尼亚州钻探的钻孔，其中包括重要的地球范围目标，如圣安德烈亚斯断层系统（SAFS），长谷和山沙斯塔/医学湖地区。然而，我们将尽一切努力记录太平洋西北地区计划钻探的应变仪钻孔。热过程对EarthScope的重要性在“互补地球物理学”和“EarthScope背景下的热过程”两个研讨会上得到了强调。此外，PBO指导委员会在2004年PBOSC年度审查中建议在应变仪钻孔中记录温度。我们建议收集和传播这些重要数据。这项研究的广泛的社会领域包括更好地理解断层，特别是圣安德烈亚斯断层，以及人为的气候变化。此外，该提案促进了学术地球科学界和美国地质勘探局之间的合作。该提案将用于教育和培训研究生。这项建议的结果将通过EarthScope网站、国家和国际会议以及同行评议文献传播。

The overarching goal of EarthScope is to elucidate the dynamics and evolution of the North American continent. To reach this goal, focused studies of the continental seismic structure, the strength of the lithosphere and modes of deformation, the patterns of stresses and strain and the manner in which the lithosphere responds to excitation during earthquakes are all a high priority. The common factor linking these EarthScope objectives is the thermal state of the lithosphere. Heat flow observations provide the strongest observational constraint on the thermal state of the lithosphere. Given the relevance of subsurface thermal conditions to the physical processes governing the spatial and temporal variations of lithospheric deformation, a greater knowledge of the subsurface thermal regime will contribute greatly to the overall objectives of EarthScope generally, and the Plate Boundary Observatory (PBO) experiment specifically. We will collaborate (Oregon State University, University of Utah and U.S. Geological Survey) in a thermal investigation of the active plate boundary between the Pacific and North American plates in the western United States. Thermal measurements will becollected in PBO boreholes currently scheduled for drilling. The field component consists of thermal logging and the determination of thermal physical rock properties. Holes will be logged between the end of drilling and the beginning of strainmeter installation so as to not disrupt PBO operations. Thermal physical rock properties will be measured using modern laboratory techniques. For both logistical and economic reasons we limit this proposal to boreholes drilled in California which includes important EarthScope targets such as the San Andreas Fault System (SAFS), Long Valley, and Mt. Shasta/Medicine Lake areas. However we will make every effort to log strainmeter boreholes scheduled for drilling in the Pacific Northwest.The importance of thermal processes for EarthScope was highlighted in two workshops, "Complementary Geophysics", and "Thermal Processes in the Context of EarthScope". Additionally, the PBO steering committee has recommended that temperatures be logged in strain meter boreholes in the 2004 PBOSC Annual Review. We propose to collect and disseminate these important data. Broad societal areas of this research include a better understanding of faulting especially the San Andreas, and anthropogenic climate change. Further this proposal fosters collaborations between the academic Earth science community and the USGS. The proposal will be used to educate and train a graduate student. Results from this proposal will be disseminated through the EarthScope web site, national and international meetings, and peer reviewed literature.