Frontispiece. The University of Hawaii operates a broadband three-component seafloor seismometer at the Hawaii-2 Observatory (Duennebier et al., 2000, 2002). While drilling at the site, data from the observatory showed environmental noise as well as drilling-related noise from the JOIDES Resolution. A. These time series of vertical motion of the seafloor show four wave packets of fin-back whale songs. For each wave packet the whale emits a wavelet ~1 s long. The four wavelets in each wave packet correspond to various sound propagation paths in the ocean. Although we did not visually observe whales while we were at Site 1224, whale calls were frequently observed in the seismic data. B. Root-mean-square (RMS) levels are a convenient way to summarize the seismic data. This figure shows RMS levels of horizontal motion in an octave band centered at 8 Hz for 7 January 2002. The T-phases from three earthquakes as well as drawworks noise from the JOIDES Resolution can be identified.

References

Duennebier, F.K., Butler, R., Chave, A., Harris, D., Jolly, J., and Babinec, J., 2000. Broadband seismograms from the Hawaii-2 Observatory [paper presented at Am. Geophys. Union Mtg., San Francisco, Fall 2000].

Duennebier, F.K., Harris, D.W., Jolly, J., Babinec, J., Copson, D., and Stiffel, K., 2002. The Hawaii-2 Observatory seismic system. IEEE J. Oceanic Eng., 27:212217.