Use of low‐frequency marine seismo‐acoustics in understanding earthquake processes: Applications to the Great Sumatra‐Andaman earthquake

Low‐frequency (1–100 Hz) hydroacoustic recordings can provide a wealth of information on earthquake characteristics in the shallow marine environment. This frequency band, considered low frequency for acousticians, is actually high frequency for regional or global seismologists who commonly work with frequencies of a few Hz and below. In some cases this higher frequency data may provide higher resolution of some earthquake characteristics than traditional seismic methods. The 2004 Great Sumatra‐Andaman earthquake provides an example where detailed analysis of the T‐wave arrival has allowed detailed characterization of changes in rupture velocity that have not proven easy to resolve in traditional seismic data. Our single‐station interpretation of the T‐wave data shows that the fault ruptured northward from the epicenter in at least two phases with lower rupture velocity in the north. The methods behind this single station approach will be discussed along with possible future uses of this type of data for ...