Fig. 1: Generation of earthquake infrasound.
From: Remotely imaging seismic ground shaking via large-N infrasound beamforming
The earthquake infrasound begins with upward-propagating primary infrasound converted at the recording site’s ground surface, followed by secondary infrasound arrivals that propagate sub-horizontally from the two hills and arrive at the array almost simultaneously. Slowness component labels describe horizontally-diffracted secondary infrasound (3 s km-1 horizontal slowness) and vertical primary infrasound (near-zero horizontal slowness).
