RRS James Cook JC209
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Cook (740H) |
| Cruise identifier | JC209 |
| Cruise period | 2020-09-01 — 2020-10-22 |
| Status | Completed |
| Port of departure | Southampton, United Kingdom |
| Port of return | Southampton, United Kingdom |
| Purpose | Research |
| Objectives | The primary aim of cruise JC209 was to recover 12 Ocean Bottom Seismometers (OBS) and a Vertically-oriented Hydrophone Array (VHA) from the seabed along the Congo Canyon offshore West Africa. These OBS and VHA had been previously deployed in September 2019 on research cruise JC187, together with 11 oceanographic moorings with ADCPs and other sensors. The moorings were impacted by a very powerful (5-8 m/s) seafloor sediment flow (turbidity current) on 14-16 January 2020, such that the moorings surfaced, and 9 moorings were recovered successfully via other vessels.
The first aim of this cruise (JC209) was therefore to recover the remaining seabed equipment. This recovery cruise was originally scheduled for April 2020, but had to be delayed to September-October 2020 due to the ongoing travel and quarantine restrictions resulting from the CoV-19 global pandemic. The second aim of the cruise was to complete a series of swath bathymetric surveys of the Congo Submarine Canyon and Channel system, soon after the prodigious submarine flow in January 2020. This post-event survey could then be compared to a survey during the 2019 JC187 cruise, to see how the seabed has changed. This helps us to understand how these submarine flows sculpt the seabed, and thus better understand the hazards to seafloor cables that now carry over 99% of global intercontinental data traffic. The wider aims of the OBS and VHA deployments are to develop novel low-cost sensor systems that can remotely record submarine turbidity currents, from sites located out of harm’s way (and outside the main canyon and channel floor). The need for such sensor systems is well illustrated by damage to the 11 oceanographic moorings by the January 2020 flow, which caused the moorings to surface. JC209 was very successful, especially in challenging circumstances due to global CoV-19 pandemic. Ten of the twelve OBS, and the Vertical Hydrophone Array, were recovered successfully. Detailed swath bathymetric surveys were completed for the floor of the upper Congo Canyon within Angolan Territorial Waters, and along the deeper-water channel within International Waters. The recovered OBS appear to have successfully recorded the January 2020 submarine flow event, whilst the repeat surveys show significant change to the seabed due to submarine flow(s) between September 2019 and September 2020. |
| Chief scientist | Peter J Talling (University of Durham Department of Geography) |
| Cruise report |  (2.48 MB) |
| Ocean/sea areas | |
| General | South East Atlantic Ocean (limit 20W) |
| Specific | Gulf of Guinea in the Eastern Atlantic. Data come from the Congo Submarine Canyon and Fan. |
| Measurements | |
| Geology and geophysics | |
| Multi-beam echosounding | Quantity: number of surveys = 2 Description: EM122 Swath Multibeam surveys |
| Moorings, landers, buoys | |
| Geology and geophysics | |
| Other geological/geophysical measurements | 6° 13' 59" S 6° 25' 29" E — Ocean Bottom Seismometer (German OBS 1) |
| Other geological/geophysical measurements | 5° 57' 48" S 11° 31' 42" E — Ocean Bottom Seismometer (OBIC-2) |
| Other geological/geophysical measurements | 5° 55' 57" S 11° 27' 16" E — Ocean Bottom Seismometer (OBIC-3) |
| Other geological/geophysical measurements | 5° 54' 28" S 11° 27' 24" E — Ocean Bottom Seismometer (OBIC-4) |
| Other geological/geophysical measurements | 5° 54' 35" S 11° 19' 54" E — Ocean Bottom Seismometer (OBIC-1) |
| Other geological/geophysical measurements | 5° 45' 15" S 8° 7' 37" E — Ocean Bottom Seismometer (OBIC-6) |
| Other geological/geophysical measurements | 5° 45' 52" S 7° 51' 54" E — Ocean Bottom Seismometer (OBIC-7) |
| Other geological/geophysical measurements | 5° 46' 28" S 7° 16' 9" E — Ocean Bottom Seismometer (OBIC-8) |
| Other geological/geophysical measurements | 5° 44' 7" S 7° 37' 58" E — Ocean Bottom Seismometer (OBIC-10) |
| Other geological/geophysical measurements | 5° 50' 51" S 11° 1' 52" E — Ocean Bottom Seismometer (OBIC-5) |
