Improved locations for global seismic events using surface waves

使用表面波改进全球地震事件的位置

• 批准号: 1520657
• 负责人: Goran Ekstrom
• 金额: $ 20万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1520657&HistoricalAwards=false
• 关键词: Improved; locations; global; seismic; events

The project will develop new methods for locating earthquakes in remote areas of the world with greater precision. Current methods of earthquake location, based on classical techniques that are used routinely by agencies such as the United States Geological Survey, the International Seismological Centre, and the International Monitoring System, provide no better than 25-km precision in earthquake location in many areas of the world. This lack of precision limits the ability to attribute individual earthquakes to specific earthquake faults, and thus also the possibility to understand better the tectonic context. The project will develop new algorithms based on inter-event correlations of intermediate-period surface waves, and is expected to lead to a location precision of 5 km or better. The algorithm will be used to address questions of plate-boundary tectonics and seismogenesis. The improvements in earthquake location will lead to new data sets with broad utility for research in plate tectonics, plate-boundary processes and global seismic tomography.The new algorithm is based on cross correlation of surface-wave signals from nearby earthquakes recorded on common stations. Effects of wave propagation between the earthquakes and the stations are canceled out, and the remaining signal is related to the propagation time delay between the stations, and to predictable source effects. The results are improved by correcting for laterally varying dispersion. The approach will make use of all available pairs of Rayleigh and Love waves for a regional cluster of earthquakes to invert for relative locations of all events in the cluster. The cluster will then be anchored to geomorphological features to provide absolute locations of the individual earthquakes.

该项目将开发新的方法，以便更精确地确定世界偏远地区的地震位置。目前的地震定位方法是基于美国地质调查局、国际地震中心和国际监测系统等机构经常使用的经典技术，在世界许多地区，地震定位的精度不超过25公里。这种精确度的缺乏限制了将个别地震归因于特定地震断层的能力，从而也限制了更好地理解构造背景的可能性。该项目将根据中间周期表面波的事件间相关性开发新的算法，预计定位精度将达到5公里或更高。该算法将用于解决板块边界构造和地震成因的问题。地震定位方面的改进将产生新的数据集，对板块构造、板块边界过程和全球地震层析成像的研究具有广泛的用途，新的算法是基于普通台站记录的邻近地震的面波信号的互相关。波在地震和台站之间传播的影响被抵消，剩余的信号与台站之间的传播时间延迟和可预测的震源效应有关。通过对横向变化的色散进行校正，结果得到改善。该方法将利用所有可用的瑞利波和洛夫波的区域集群的地震，以反演集群中的所有事件的相对位置。然后，该集群将被锚定到地貌特征，以提供单个地震的绝对位置。