Improved locations for global seismic events using surface waves

该项目将开发新的方法来更精确地定位世界偏远地区的地震。目前的地震定位方法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，在世界许多地区提供的地震定位精度不超过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了解构造背景的可能性。该项目将根据中周期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问题。地震定位的改进将带来新的数据集，在板块构造、板块边界过程和全球地震层析成像研究中具有广泛的实用价值。新算法基于普通台站记录的邻近地震的面波信号的互相关。地震和台站之间波传播的影响被抵消，剩余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，改进了结果。该方法将利用地区性地震群的所有可用的瑞利波和乐夫波对来反演该地震群中所有事件的相对位置。然后，该集群将固定在地貌特征上，以提供个别地震的绝对位置。

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.