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

地球镜的首要目标是阐明北美大陆的动态和演变。为实现这一目标，重点研究大陆地震结构、岩石圈强度和变形模式、应力和应变模式以及地震期间岩石圈对激发的反应方式，都是一个高度优先事项。联系这些地球镜目标的共同因素是岩石圈的热状态。 热流观测对岩石圈的热状态提供了最强的观测约束。考虑到地下热状况与控制岩石圈变形时空变化的物理过程的相关性，对地下热状况的更多了解将大大有助于EarthScope的总体目标，特别是板块边界观测台（PBO）实验。我们将与（俄勒冈州州立大学、犹他州大学和美国地质调查局）合作，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。将在目前计划钻探的PBO钻孔中收集热测量值。现场部分包括热测井和岩石热物理性质的测定。在钻孔结束和应变仪安装开始之间记录钻孔，以免中断PBO操作。将使用现代实验室技术测量岩石的热物理性质。出于后勤和经济方面的原因，我们将此建议限制在加州的钻孔范围内，其中包括重要的EarthScope目标，如圣安德烈亚斯断层系统（SAFS）、长谷和Mt.沙斯塔/医学湖地区。然而，我们将尽一切努力记录计划在太平洋西北部钻探的应变计钻孔。在两个研讨会上，“补充地球物理学”和“EarthScope背景下的热过程”，强调了热过程对EarthScope的重要性。此外，PBO指导委员会在2004年PBOSC年度审查中建议在应变计钻孔中记录温度。 我们建议收集和传播这些重要数据。这项研究的广泛社会领域包括更好地了解断层，特别是圣安德烈亚斯断层，以及人为气候变化。此外，这一建议促进了地球科学学术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一名研究生。这一建议的结果将通过地球镜网站、国家和国际会议以及同行审查的文献传播。

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.