Using ambient seismic noise to determine short-period phase velocities and shallow shear velocities in young oceanic lithosphere

Using 10 broadband ocean bottom seismometers from the 11-month-long deployment of the Gravity Lineations Intraplate Melting Petrologic and Seismologic Expedition (GLIMPSE) passive seismic experiment located in the south central Pacific, we have estimated the seismic impulse responses from ambient seismic noise for 45 station-to- station paths. The raw impulse responses show moveout with stationto-station distance, and there is a trend of decreasing signal-to-noise ratios as the station-to-station distance increases. The decrease in signal-to-noise ratio is expected as a smaller range of azimuths of propagating surface waves will contribute constructively to the cross-correlated signal with increasing distance, although scattering may also play a role in the coherence of seismic noise at periods less than 16 sec.