Using hydroacoustic stations as water column seismometers

TitleUsing hydroacoustic stations as water column seismometers
Publication TypeJournal Article
Year of Publication2013
AuthorsYildiz S., Sabra K., Dorman L.M, Kuperman WA
JournalGeophysical Research Letters
Date Published2013/06
Type of ArticleArticle
ISBN Number0094-8276
Accession NumberWOS:000321261600018
Keywordsarray processing; CTBTO; earthquake; hydroacoustics; indian-ocean; low frequency; seismometer

Getting seismic data from the deep oceans usually involves ocean-bottom seismometers, but hydrophone arrays may provide a practical alternative means of obtaining vector data. We here explore this possibility using hydrophone stations of the International Monitoring System, which have been used to study icebergs and T-wave propagation among others. These stations consist of three hydrophones at about the depth of the deep sound channel in a horizontal triangle array with 2km sides. We use data from these stations in the very low-frequency regime (0.01-0.05Hz band) to demonstrate that these stations can also be used as water column seismometers. By differencing the acoustic pressure, we obtain vector quantities analogous to what a seismometer would record. Comparing processed hydrophone station records of the 2004 Great Sumatra-Andaman Earthquake with broadband seismograms from a nearby island station, we find that the differenced hydrophones are indeed a practical surrogate for seismometers.