Cruise inventory

RRS James Cook JC109

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Cook (740H)
Cruise identifierJC109
Cruise period2014-10-11 — 2014-11-05
Port of departureSouthampton, United Kingdom
Port of returnPort of Spain, Trinidad and Tobago
ObjectivesThe primary purpose of this cruise was to recover an array of 25 ocean-bottom seismographs, which had been recording passive micro-seismicity data at the 13° 20'N oceanic core complex on the Mid-Atlantic Ridge since they were deployed during JC102 in April 2014. This array of seismographs was recording local seismic events associated with extension-related slippage on the fault planes that accommodate spreading at this plate boundary. The data will be used to test models of plate accretion at slower spreading rates. This cruise is the second of three: i) passive array deployment; ii) passive array recovery; and iii) active source seismic imaging, coupled with Autosub near-seabed geophysical and oceanographic surveying. This cruise comprised a transit to the work area of ~11.5 days, ~2.25 days of OBS recovery, 3.25 days of swath bathymetry data in-fill in the work area and a transit from the work area of ~5 days - a total of ~22 days. Four days were lost to a delayed departure from Southampton due to rectification works on and recertification of the lifeboats and HMRC custom clearance. Swath bathymetry and gravity data were acquired throughout the transits to/from ports as well as in the study area.
Chief scientistChristine Peirce (University of Durham, Department of Earth Sciences)
Cruise reportRRS James Cook JC109 cruise report jc109.pdf — access key 'C' (9.50 MB) 
Ocean/sea areas 
GeneralNorth West Atlantic Ocean (limit 40W)
SpecificMid-Atlantic Ridge
Track chartsRRS James Cook JC109 cruise track — jc109trk.pdf (0.21 MB) 
Geology and geophysics 
Geophysical measurements made at depthQuantity: number of stations = 1
Description: Sound velocity measurement from surface to 1000m depth - using dual Valeport Midas sound velocity probes
Single-beam echosoundingQuantity: activity duration in days = 22
Description: Single beam bathymetry - using a Kongsberg EA600 12 kHz
Multi-beam echosoundingQuantity: activity duration in days = 22
Description: Multibeam bathymetry - using an Kongsberg EM120 in deep mode 191/191 beams, maximum angle 70°/70°, beam width 7000m/7000m in good sea conditions
Seismic refractionQuantity: number of deployments = 25
Description: Ocean-bottom seismograph (OBS)
Gravity measurementsQuantity: activity duration in days = 22
Description: Gravity - using a LaCoste Romberg sea gravity meter (instrument S-040)
Other geological/geophysical measurementsQuantity: activity duration in days = 198
Description: Passive seismicity data - using ocean-bottom seismographs, comprising 3-component geophones and either a hydrophone or differential pressure gauge as sensors