Noise cross-correlation and beamforming with the Cascadia Initiative data

The Cascadia Initiative (CI) contains many seismic stations located onshore and offshore. The proximity of all the stations to the coast presents a unique opportunity to study the source locations of microseisms. We use both cross-correlation and beamforming method to estimate horizontal phase slownesses and directions of the microseisms for both OBS and land arrays. Microseisms originating from the shallow water appear to come from different directions for these two subarrays. Whereas deep water microseisms further offshore appear to come from the same direction.