Passive hydrophone technologies and a variety of acoustic methods are applied in
the deep-ocean and shallow water coastal environments of the northeast Pacific. A
catalog derived from U.S. Navy regional hydrophone array recordings of acoustic T- phases from seafloor earthquakes is examined, describing space/time patterns through
empirical orthogonal function analysis...
Hydroacoustic tertiary (T-) waves are seismically generated acoustic waves that propagate
over great distances in the ocean sound channel with little loss in signal strength.
Hydrophone recorded T-waves can provide a lower earthquake detection threshold and an
improved epicenter location accuracy for oceanic earthquakes than land-based seismic
networks. Thus detection...
Plate boundaries are commonly regions of complex, diffuse deformation with
the motion across the boundary accommodated by numerous structural systems, rather
than being narrow, discrete zones of deformation. One such boundary occurs where
the North American plate makes contact with Juan de Fuca, Gorda, and Pacific plates
along the west...
Full-coverage multibeam bathymetric mapping of twelve seamounts in the Gulf of Alaska reveals that
they are characterized by flat-topped summits (rarely with summit craters) and by terraced, or step-bench,
flanks. These summit plateaus contain relict volcanic features (e.g., flow levees, late-stage cones, and
collapse craters) and as such must have...
Mid-ocean ridge volcanism and extensional faulting are the fundamental processes that lead to the creation and rifting of oceanic crust, yet these events go largely undetected in the deep ocean. Currently, the only means available to observe seafloor-spreading events in real time is via the remote detection of the seismicity...
Using a short-baseline hydrophone array, persistent volcanoacoustic sources are identified within the ambient noise field of the Lau Basin during the period between 2009 January and 2010 April. The submarine volcano West Mata and adjacent volcanic terrains, including the northern Matas and Volcano O, are the most active acoustic sources...
A network of autonomous underwater hydrophones is used to monitor acoustic activity associated with Hunga Ha'apai-Hunga Tonga volcano during a period of 15 months. The data provide a continuous record spanning a surtseyan eruption (VEI 2) in March of 2009, which input ~10¹³ J of acoustic energy into the ocean...
During January–February 2009, an active-source seismic survey was performed over the Eastern Lau Spreading Center in the Lau Back-Arc Basin (21°S, 176°S). Acoustic signals generated by the R/V Langseth's 36-gun pneumatic source array were recorded within the deep sound channel at offsets of 29–416 km. The local ocean acoustic environment...
Acoustic methods are frequently used to monitor endangered marine mammal species. Advantages of acoustic methods over visual ones include the ability to detect submerged animals, to work at night, and to work in any weather conditions. A relatively inexpensive and easy-to-use acoustic float, the QUEphone, was developed by converting a...
Submarine volcanic eruptions and intrusions construct new oceanic crust and build long chains of volcanic islands and vast submarine plateaus. Magmatic events are a primary agent for the transfer of heat, chemicals, and even microbes from the crust to the ocean, but the processes that control these transfers are poorly...