IGPP, La Jolla
Email:
vera@igppmail.ucsd.edu
poster/oral: poster
| Continuous beamforming on noise recorded at land arrays reveals that ocean-generated microseisms arrive on discrete azimuths. Transitions into different azimuth modes are triggered by regional swell events. This contradicts the idea that microseisms, in particular the higher amplitude peak at twice the predominant swell frequency, are partly of pelagic origin and can be used to track storms, as frequently postulated in the literature. The azimuths of primary versus double-frequency microseisms differ owing to separate mechanisms of ocean-land coupling and differences in propagation. Characteristics of land microseisms seem to be dictated by coastal geometry and regional crustal structure, which opens the possibility of studying the mechanisms of coupling as well as path effects on short-period Rayleigh waves on land. |