Collaborative Research: Post-Katrina Re-Survey of Key Geodetic Benchmarks in Coastal Louisiana

合作研究：卡特里娜飓风过后路易斯安那州沿海地区主要大地测量基准的重新调查

• 批准号: 0609742
• 负责人: Timothy Dixon
• 金额: --
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609742&HistoricalAwards=false
• 关键词: Collaborative; Research; Post; Katrina; Re

0609742DixonFunds from this Small Grant for Exploratory Research (SGER) support a collaborative effort by PIs Tim Dixon (Miami - RSMAS) and Roy Dokka (LSU) to conduct GPS resurveys of existing campaign benchmarks in the New Orleans area and to establish 10 additional continuously operated and permanently monumented GPS stations in the region. The recent tragic flooding of New Orleans, Louisiana, associated with Hurricane Katrina on August 29, 2005, emphasizes the hazardous setting of this urban area. Preliminary GPS and leveling data collected by the PIs suggest that New Orleans is subsiding rapidly because it is located in the hanging wall of an active listric normal fault system (the Michoud fault) that accommodates southward motion of the Mississippi delta into the Gulf of Mexico. Averaged over the last decade, southward motion of this upper crustal block relative to the stable interior of North America occurs at a rate of 2.3 plus or minus 1.7 mm/yr. Leveling data suggest that the rate of motion may have been higher in the recent past. The average subsidence rate for GPS sites located on the delta is 5.2 plus or minus 2.3 mm/yr relative to Earths's center of mass, or about 7 mm/yr relative to mean sea level. Movement of the delta block on the listric fault appear to be facilitated by underlying salt horizons that have been imaged by seismic reflection campaigns. These horizons accommodate deformation via ductile flow at low temperatures, hence there is little or no seismicity associated with faulting. The proposed additional GPS observations will help to confirm the proposed Michoud fault dynamics and to test the possibility that ground deformation accelerated following Katrina-related water mass loading. Data from this project will provide critical background tectonic framework to guide policy makers during the rebuilding of New Orleans.***

0609742DixonFunds from this Small Grant for Exploratory Research (SGER) support a collaborative effort by PIs Tim Dixon (Miami - RSMAS) and Roy Dokka (LSU) to conduct GPS resurveys of existing campaign benchmarks in the New Orleans area and to establish 10 additional continuously operated and permanently monumented GPS stations in the region. 2005年8月29日，与卡特里娜飓风相关的新奥尔良最近发生的悲惨洪水强调了这一市区的危险环境。 PIS收集的初步GPS和升级数据表明，新奥尔良正在迅速降低，因为它位于活跃的Listric正常断层系统（Michoud Wurd）的悬挂墙中，该系统可容纳密西西比三角洲向南运动进入墨西哥湾。 在过去的十年中，该上层地壳的向南运动相对于北美稳定的内部，其速度为2.3加或减1.7毫米/年。升级数据表明，最近的运动速度可能较高。相对于地球的质量中心，位于三角洲的GPS位点的平均沉降率为5.2 plus或减去2.3 mm/yr，或相对于平均海平面的约7 mm/yr。通过地震反射运动成像的基础盐层，三角洲块上的运动似乎有助于促进。这些地平线在低温下通过延展性流量适应变形，因此与断层相关的地震性很小。 拟议的其他GPS观察将有助于确认提出的Michoud断层动态，并测试与卡特里娜飓风相关的水量加载后地面变形加速的可能性。 该项目的数据将提供关键的背景构造框架，以指导新奥尔良重建期间的决策者。***