The Impact of Seismic Wavefield and Source Properties on ReMi Estimates

The Refraction Microtremor (ReMi) method has recently been introduced to estimate the Rayleigh seismic surface wave phase velocity with passive sources. The ReMi method utilizes the p-τ algorithm to estimate wave velocity with a linear array of sensors. Relying on the observation that, in a wavefield with equal energy impinging from all directions, 40.9% of the wave velocity will be within 100 to 125% of the expected phase velocity, ReMi attempts to determine the fundamental mode phase velocity in a passive energy environment with a linear array. This paper will show that, due to material attenuation, multiple modes and varying direction of arrivals, ReMi does not yield reliable results. Using simulated data, the fundamental performance of ReMi in different realistic wavefield environments is studied.