Accuracy of Absolute Earthquake Location with Ambient Seismic Noise via Ground Truth Event Experiment

Abstract:

The absolute earthquake location with high precision is the key to determine the seismogenic fault. Nonetheless, it is very challenging to achieve high accuracy location in the sparse seismic network. Recently ambient seismic noise has been demonstrated to be able to achieve 2km or better accuracy of earthquake location, using the noise cross-correlation function (NCF) between the stations near the epicenter and distant stations, where similar path between the epicenter and the corresponding station helps to reduce the location error caused by the velocity structure variation. This method is not systematically investigated yet, hence we have installed a portable seismic station around Suining earthquake, a ground truth event observed by InSAR, and applied the bootstraping method to investigate effects upon location accuracy due to number of stations, epicentral distance of station, azimuthal gap as well as seasonality of observation. Studies have indicated that ambient seismic noise location method can increase positioning accuracy with sparse network, and it is also helpful to study the historical earthquake.