Arrival angles of teleseismic fundamental mode Rayleigh waves across the AlpArray

Petr Kolínský (1) , Götz Bokelmann (1)

1 IMGW - Institut für Meteorologie und Geophysik [Wien]

The dense AlpArray network allows studying seismic wave propagation with high spatial resolution. Here we introduce an array approach to measure arrival angles of teleseismic Rayleigh waves. The approach combines the advantages of phase correlation as in the two-station method with array beamforming to obtain the phase-velocity vector. 20 earthquakes from the first two years of the AlpArray project are selected, and spatial patterns of arrival-angle deviations across the AlpArray are shown in maps, depending on period and earthquake location. The cause of these intriguing spatial patterns is discussed. A simple wave-propagation modelling example using an isolated anomaly and a Gaussian beam solution suggests that much of the complexity can be explained as a result of wave interference after passing a structural anomaly along the wave paths. This indicates that arrival-angle information constitutes useful additional information on the Earth structure, beyond what is currently used in inversions.

Keywords: Structure of the Earth; Europe; Time-series analysis; Surface waves and free oscillations; Wave propagation; Wave scattering and diffraction

Domains: Geophysics [physics.geo-ph]

Petr Kolínský, Götz Bokelmann. Arrival angles of teleseismic fundamental mode Rayleigh waves across the AlpArray. Geophysical Journal International, 2019, 218 (1), pp.115-144. ⟨10.1093/gji/ggz081⟩. ⟨insu-02281701⟩