Optimize the Stacking of Noise Correlation Functions

Session: Advances in Seismic Interferometry: Theory, Computation and Applications [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The cross-correlation of ambient seismic noise provides propagation information of seismic waves in the three dimensional Earth. The noise correlation function (NCF) has been widely used to image the Earth’s velocity structure, to model earthquake ground motions and to monitor transient velocity changes for shallow subsurface. A common step in extracting NCFs is the stacking of individual correlations performed over short time windows, e.g. a day or an hour, over a longer period. However, one important characteristic that is commonly ignored in stacking is the temporal variation of NCFs. This temporal variation may result from the change of seasonal microseisms, the contamination from local transient signals, such as earthquakes and tremors and the influence of instrument performance. These factors lead to noisy or useless NCFs, which would consequently contaminate the final stack. In this study, we explore and evaluate a variety of methods to optimize the final stack of NCFs. We focus on mitigating the effects of the temporal variation of NCFs through removing transient seismic signals before cross-correlations and stacking techniques after cross-correlations over short time windows.

Presenting Author: Xiaotao Yang

Authors