Collaborative Research: High Sample-Rate GPS - A New Tool for Earthquake Studies/University of Colorado, University of Memphis, and Purdue University

合作研究：高采样率 GPS——地震研究的新工具/科罗拉多大学、孟菲斯大学和普渡大学

• 批准号: 0337108
• 负责人: Paul Bodin
• 金额: $ 5.38万
• 依托单位: University of Memphis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337108&HistoricalAwards=false
• 关键词: Collaborative; Research; Sample; Rate; GPS

Collaborative Research: High Sample-Rate GPS: A New Tool for Earthquake StudiesUnderstanding fault rupture during major earthquakes, and the resulting ground motions, is limited by our observational capabilities. Observations of very large amplitude seismic waves, especially direct measurements of displacement, would make a significant improvement in constraining the size of dynamic strains that trigger remote seismicity and in revealing details of the source rupture process. For example, accelerometers capture the details of strong ground shaking near the source, but it is difficult to convert the acceleration measurements unambiguously to displacement which is required for determining the source time history. Broad-band seismometers are more sensitive, and have better resolution of ground motion, but frequently clip, saturate, or become non-linear even at great distances from a large earthquake. Interferometric Synthetic Aperture Radar (InSAR) observations can produce spatially rich images of some components of surface displacement surrounding a rupture, but InSAR fails in many regions and has no temporal resolution to resolve dynamic phenomena. Global Positioning System (GPS) geodetic measurements have been important for resolving static offsets, but are usually sampled at such a low rate that resolving details of the rupture process was not frequently attempted.A new technique has been developed for using high-rate measurements from GPS to measure seismic waves generated by large earthquakes. This project specifically exploits high-rate GPS measurements to improve our understanding of the rupture process of the Mw 7.9 Denali Fault earthquake of 3 November 2002. The first phase of this project assesses the technical issues relating to the reliability and utility of these new GPS observations. In the second phase, the resulting data are used to complement existing seismic data: (1) to better understand the ground motions from the Denali earthquake that triggered earthquakes remotely, and (2) to use the surface waves at far-regional distances to validate rupture models of the Denali Fault earthquake mainshock. The research proposed here has several potential societal benefits: (1) The increased understanding of stress levels required to trigger earthquakes will contribute to earthquake prediction efforts which has long term benefits to public safety; (2) GPS constraints on strong motion displacements will have a significant impact in the earthquake engineering community by increasing the amount of data available, and addressing the very problematic aspect of recovering reliable displacement records from accelerometers. This will have impacts on public safety through better understanding of building response and building safety; (3) The high-rate GPS methodology will benefit a larger community of GPS users by increasing the accuracy and efficiency of high-rate GPS data analysis. The results will also impact the infrastructure for research and education by influencing, for example, the design and implementation of GPS monitoring within the Plate Boundary Observatory component of the NSF Earthscope facility.

合作研究：高采样率GPS：地震研究的新工具了解大地震中的断层破裂以及由此产生的地面运动，受到我们观测能力的限制。对非常大振幅地震波的观测，特别是对位移的直接测量，将在限制触发远程地震活动的动态应变的大小和揭示震源破裂过程的细节方面作出重大改进。例如，加速度计捕获震源附近强烈地面震动的细节，但很难将加速度测量结果明确地转换为确定震源时程所需的位移。宽频带地震仪更敏感，对地面运动的分辨率也更高，但即使在距离大地震很远的地方，也经常出现夹波、饱和或非线性。干涉合成孔径雷达（InSAR）观测可以产生空间丰富的破裂周围地表位移分量图像，但InSAR在许多区域失效，并且没有时间分辨率来解决动态现象。全球定位系统（GPS）大地测量测量对于解决静态偏移非常重要，但通常采样率很低，因此不经常尝试解决破裂过程的细节。一种新技术已经被开发出来，可以利用GPS的高速率测量来测量大地震产生的地震波。该项目专门利用高速率GPS测量来提高我们对2002年11月3日发生的里氏7.9级德纳里断层地震破裂过程的理解。该项目的第一阶段评估与这些新的GPS观测的可靠性和效用有关的技术问题。在第二阶段，利用得到的数据来补充现有的地震数据：(1)更好地了解迪纳里地震引发的远程地震的地面运动；(2)利用远区域距离的表面波来验证迪纳里断层主震的破裂模型。这里提出的研究有几个潜在的社会效益：(1)增加对触发地震所需的应力水平的了解将有助于地震预测工作，这对公共安全有长期的好处；(2) GPS对强运动位移的限制将对地震工程界产生重大影响，因为它增加了可用数据的数量，并解决了从加速度计中恢复可靠位移记录的非常有问题的方面。这将通过更好地了解建筑反应和建筑安全，对公共安全产生影响；(3)高速率GPS方法学通过提高高速率GPS数据分析的精度和效率，使更多的GPS用户受益。研究结果还将影响研究和教育的基础设施，例如影响美国国家科学基金会Earthscope设施板块边界观测站组件内GPS监测的设计和实施。