title: Tracking fin whales in the northeast Pacific Ocean with a seafloor seismic network.
abstract: Ocean bottom seismometer (OBS) networks represent a tool of opportunity to study fin and blue whales. A small OBS network on the Juan de Fuca Ridge in the northeast Pacific Ocean in ~2.3 km of water recorded an extensive data set of 20-Hz fin whale calls. An automated method has been developed to identify arrival times based on instantaneous frequency and amplitude and to locate calls using a grid search even in the presence of a few bad arrival times. When only one whale is calling near the network, tracks can generally be obtained up to distances of ~15 km from the network. When the calls from multiple whales overlap, user supervision is required to identify tracks. The absolute and relative amplitudes of arrivals and their three-component particle motions provide additional constraints on call location but are not useful for extending the distance to which calls can be located. The double-difference method inverts for changes in relative call locations using differences in residuals for pairs of nearby calls recorded on a common station. The method significantly reduces the unsystematic component of the location error, especially when inconsistencies in arrival time observations are minimized by cross-correlation.
authors.affiliation: School of Oceanography, University of Washington, Seattle, Washington 98195-7940, USA. wilcock@u.washington.edu
authors.forename: William S D
authors.initials: WS
authors.lastname: Wilcock
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000465:Algorithms; D000818:Animals; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D050617:Fin Whale / Q000502:physiology*; D019015:Geologic Sediments; D008962:Models, Theoretical; D009038:Motion; D010140:Pacific Ocean; D011156:Population Density; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors; D014828:Vocalization, Animal; D014867:Water
chemical_list: D014867:Water