R. Burlacu¹ , K.D. Koper¹

¹University of Utah

Abstract:

We process continuous data downloaded from the IRIS Data Management Center and recorded at the TA array in Alaska to detect and locate P-wave microseisms using a backprojection method. We backproject the energy to a series of grid points covering the entire Earth, with ~400 km spacing. For each grid point —and an assumed origin time — 10 min data from each element of the Alaska TA array is extracted, starting with the predicted P-wave arrival time by the 1D ak135 velocity model. For each trace, the processing involves, in succession, removing the trend and applying a filter and a taper. All traces in the array, at distances of 30–90 deg from the grid point, are stacked using a fourth-root stacking method, and the root-mean-square amplitude of the stack is assigned as the power of the specific stack. The procedure is repeated for each grid point and for origin times incremented by 5 min. The backprojection method is applied to data recorded at the Alaska TA array during 2018. We estimate the sources of P-wave microseisms in the Atlantic and Pacific Oceans and compare them with predictions of wave-wave interactions from ocean models developed under the WAVEWATCH III framework.