Field Data Collection

Marine Vibracores

The 10CCT05 vibracores were collected from the 50-foot (ft; 15-meter (m)) USGS research vessel R/V G.K. Gilbert using a hydraulic crane to position, deploy, and recover the vibracore rig. A Rossfelder model P-3 electric motor encased in a waterproof housing driving offsetting concentric weights was used to vibrate a 3.0-inch (in; 7.6 centimeter (cm)) diameter by 20-ft (6.1 m) long aluminum core barrels into the sediment (figs. 3, 4, and 5). For each core site, the core number, location, water depth, and recovered core length as well as any other relevant information were recorded in a handwritten logbook. A more detailed description of the USGS vibracoring system components and processes is available online at https://pubs.usgs.gov/of/1998/of98-805/html/polloni3.htm. For a USGS podcast of the vibracoring procedure go to http://gallery.usgs.gov/videos/534.

Figure 3. The R/V G.K. Gilbert collecting a marine core with hydraulic crane, motor, and core barrel (photo taken in Tampa Bay, offshore St. Petersburg, FL).

Figure 4. Vibracore after being brought up to the boat. The bottom of the core has been capped and taped and is pictured being lowered back down to cut and tape the top (photo taken in Tampa Bay, offshore St. Petersburg, FL). Figure 5. Vibracore rig being deployed to seafloor with hydraulic crane aboard the R/V G.K. Gilbert.