Separation and location of microseism sources

Abstract

Microseisms are ground vibrations caused largely by ocean gravity waves. Multiple spatially separate noise sources may be coincidentally active. A method for source separation and individual wavefield retrieval of microseisms using a single pair of seismic stations is introduced, and a method of back azimuth estimation assuming Rayleigh-wave arrivals of microseisms is described. These methods are combined to separate and locate sources of microseisms in a synthetic model and then applied to field microseismic recordings from Ireland in the Northeast Atlantic. It is shown that source separation is an important step prior to location for both accurate microseism locations and microseisms wavefield studies. Key Points Back-azimuth estimation prior to source separation gives incorrect results Back-azimuths of separated sources are estimated using phase difference analysis Separation improves relationships between wave climate and microseisms ©2013. American Geophysical Union. All Rights Reserved.