Here are some useful vocab words that may appear in our blog posts. I’ve attached some pictures below as well!
OBS – Stands for ocean bottom seismometer. This instrument is lowered over the side and rests on a tripod on the seafloor. It measures any and all seismic (earthquake) activity.
TRM – Stands for Trawl Resistant Mount. This housing was designed and built at Columbia’s Lamont-Doherty campus. For shallower water OBS sites, where trawl fishing is common, the TRM is used to protect the OBS and guide the trawling lines over the instrument without dragging damage.
Jason – Jason is a submersible remotely operated vehicle, designed and built by WHOI. Equipped with two hydraulic arms, a tool drawer, 8 separate cameras dedicated to piloting and the science team, countless LED lights to illuminate the workspace, and hundreds of other functions, Jason is a fully capable and versatile vehicle that is unmatched in its class.
Juan de Fuca Plate – A small plate subducting under the North American plate in the Pacific Northwest.
Subduction Zone – When two tectonic plates converge, the heavier (more dense) plate slides underneath the lighter (less dense) plate. The area where this happens is called the subduction zone because the heavier plate is subducting beneath the lighter plate.
Episodic Tremor and Slip – This phenomena is an area of debated research. The idea is that as the heavier oceanic plate (the Juan de Fuca) subducts beneath the lighter continental (North American) plate, it does not do so smoothly. Instead, where the two plates overlap, they “stick” together and build up tension. When a certain threshold is reached, the plates release and “slip” which causes minor earthquake activity.
fantail – The area at the stern of the ship where the crane, Jason, TRMs, winches, other heavy equipment are located. Recoveries and deployments happen from this part of the ship.
the bridge – This is where the ship is controlled from.
winch – The special winch we have on board was designed to help alleviate the constantly changing tension that develops in the line as the TRMs are lowered into and raised from the water. The pitch and roll of the ship has a large effect on tension felt by the line.
multi beam – This is one of the instruments that we monitor during our watches. It provides a detailed map of the seafloor in a relatively narrow swatch beneath the ship. The method by which it creates this image is complicated enough that in the six times it has been explained to me, I still don’t really know how it works…
chirp – The chirp, or ADCP, is an echo sounding device that measures the time delay from a ping that it sends to the bottom. This ping actually penetrates the sediment on the seafloor and lets us look the different layers of the seafloor. We also monitor the chirp during watch by adjusting the range to log the most relevant images of the sediment.
watch-standing – We are on a simple 4 hours on/8 hours off schedule. Our duties include (briefly): monitoring the computer lab equipment, logging our position, heading, depth, and activity every 30 minutes, and communicating between the lab and the bridge.
LDEO – Lamont-Doherty Earth Observatory. An affiliate of Columbia University with a campus located just northwest of Manhattan on the shore of the Hudson.
WHOI – Woods Hole Oceanographic Institute.