HR: 1340h
AN: OS43B-0545    [Abstracts]
TI: An autonomous mid-column float designed to detect earthquakes
AU: Babcock, J M
EM: jbabcock@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive,, La Jolla, CA 92093 United States
AU: * Simons, F J
EM: fjsimons@alum.mit.edu
AF: Princeton University, Department of Geosciences, Guyot Hall, Princeton, NJ 08540 United States
AU: Nolet, G
EM: nolet@princeton.edu
AF: Princeton University, Department of Geosciences, Guyot Hall, Princeton, NJ 08540 United States
AB: Two thirds of Earth's surface are virtually inaccessible to passive-source seismometry, save for expensive ocean-bottom seismometers or moored hydrophones. Here, we show our progress in the development of an independent hydro-acoustical recording device mounted on SOLO floats. Our instrument is able to maintain a constant water column depth below the sound channel and will surface only periodically for position determination and satellite data communication via the IRIDIUM protocol. A prototype has been built and taken out to the ocean for testing in November 2003 and September 2004. We have designed intelligent algorithms for the automatic identification and discrimination of seismic phases in the noisy ocean environment, combining continuous time-domain processing, spectrogram analysis, and custom-made wavelet methods. The lifespan and cost of the instrument are critically dependent on its ability to limit its power consumption by using a minimum amount of processing steps. Hence, we pay particular attention to the numerical implementation and efficiency of our algorithms. In addition to test analyses on data from ridge-tethered hydrophones we now show examples from data recently acquired in situ.
UR: http://www.frederik.net
DE: 4259 Ocean acoustics
DE: 4294 Instruments and techniques
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting