The R/V Pelican Sets Sail, and Data Collection Begins
Researchers are mapping the seafloor and subseafloor between Haiti and Jamaica, to evaluate the potential for earthquakes.
January 16, 2022
The R/V Pelican. Photo: Cecilia McHugh
The R/V Pelican departed Ocho Rios on January 8, arriving at our first location along the Jamaica Passage on January 9.
During the daytime, we run the CHIRP subbottom profiler, which lets us see an acoustic image of the seafloor and about 10 meters into the subsurface, plus the multichannel seismic survey, which penetrates much deeper into the subsurface (~100 m) in this setting. We collect sediment cores and heat flow measurements at night.
Due to rough seas with winds of 15 knots, swells as high as eight feet, and minor technical issues, the multichannel seismic survey and sub-bottom profiling were slow to start. But the coring was very successful and we recovered three gravity cores in water depths ranging from 2500 to 2700 meters.
A gravity core is a metal pipe with a very heavy weight (core head) that makes the core descend to the seafloor by the force of gravity. It penetrates the sediments beneath the seafloor and recovers layers of sediment, like a layered cake, that reveal the history of a location, with the oldest layer at the bottom and the youngest layer on top.
Together, these measurements and the ones we collect over the coming weeks will help us evaluate the potential earthquake hazard along the Enriquillo-Plantain Garden fault, located between Haiti and Jamaica.
As of January 13, all systems are fully operational and we are collecting great data.
The seismic survey is being conducted during the daytime. Photo: Cecilia McHugh
The coring system we’re using is the “Big Bertha,” with a coring head weight of 3500 pounds. It can recover up to six meters of sediment from the seafloor. Photo: Cecilia McHugh
The multicore recovers the sediment at the interface between the sediment and water allowing us to study a complete record of sedimentation and capture the most recent event deposits possibly related to earthquakes. Photo: Cecilia McHugh