“…Sonobuoys [Reid et al, 1973] have had success in the past in recording local earthquake signals, but they have been too noisy to provide an acceptable signal-to-noise ratio for all but the strongest earthquakes [Kebe, 1981;Cotaras et al, 1988]. Ocean bottom seismometers (OBS) [Zhao et al, 1997;Laske et al, 1999;Stephen et al, 2003] and moored hydrophones [Smith et al, 2004] are capable of addressing the coverage gap, but they are expensive to manufacture (~US$50,000 for a three-component OBS) and deploy (~$20,000 per day of ship time). Unable to communicate their recordings remotely without prohibitively expensive cabling, stationary underwater devices have to be retrieved at regular intervals for the data to be analyzed in the computer lab.…”