The Cascadia Initiative is an onshore-offshore seismic and geodetic experiment, using an underwater array of seismometers to measure the deformation of the Juan de Fuca and Gorda plates. The seismometers, located off the coasts of California, Oregon, Washington and Vancouver Island, need to be recovered and deployed every year in order to collect the data they contain.
Since 2011, Bill Hanshumaker, Oregon Sea Grant’s marine public educator at OSU’s Hatfield Marine Science Visitor Center in Newport, OR, has participated in the annual cruises as a means of bringing the experience of at-sea ocean research to classrooms on the shore.
For 2014, Dr. Hanshumaker is planning live Skype-to-shore sessions with selected science classrooms – if satellite Internet connections permit.
Learn more about the Cascadia Initiative from their Website.
CTD stands for conductivity, temperature and depth. These terms refer to the changing seawater characteristics that the CTD array encounters as it descends. It electrically sends continuous measurements back to the ship.
Conductivity is an electrical measurement of salinity. The salinity varies near the surface, but is a reliable 34 to 35 parts per thousand for most of the descent. The seawater temperature drops to about 3 degrees Celsius, about 37 degrees Fahrenheit.
We dropped the cabled CTD to just above the seafloor depth of 1500 meters (4921 feet). The pressure increases about one atmosphere for every 10 meters (or ~33 feet) of depth. We attached to the CTD array two nylon bags filled with Styrofoam cups, decorated by students from the Lincoln County School District. When subjected to pressure 150 times greater than standard atmospheric, the air is squeezed out from the Styrofoam.
Sea Grant's Bill Hanshumaker chronicles ocean research missions
