Geophysical data in the megascours project is going to be collected during high-flow river levels following the monsoon (in roughly June-September) and in low-flow conditions (roughly December-February). During the high-flow surveys data is collected from the water using seismic equipment which can image the topography of the river bed as well as sedimentary layers in the sediment below the river bed. In order to collect this data in such a large river system the scientific team need to live onboard a research vessel for the duration of the survey.
The vessel used for surveys is the MV Kokilmoni
The MV Kokilmoni is a 25.9m long with a 6.71m beam and 1.7m draft. It is powered by a 6-cylinder, 256 BHP GM diesel engine and has a top cruising speed of ~11 knots (~20 km/h). For collecting seismic survey data however a normal cruising speed is 2-6 knots (1-3 m/s). There are 14 cabins, a galley, an air conditioned dining room and ~32m^2 of deck space.
Power for the various survey equipment comes from two generators in the machine room (1 x 20kW, 1 x 2kW), in addition a 4.5 kVA petrol generator forms part of the scientific equipment to provide power to the seismic equipment.
Navigation is provided by an auxiliary GPS unit (Hemisphere R131 D-GPS); the vessel has no built in navigation system and the auxillary D-GPS system allows NMEA navigation strings to be split to allow real-time online tagging of navigation to seismic traces, along with providing steer-by survey lines for the pilot using HydroPro. A subscription to the OmniStar service is used during the survey period.
A technical room is set-up on the vessel to allow the scientific team to analyse and process data collected in real-time as well as post-process data, this allows informed decisions to be made during the survey voyage for where to target data collection.
Seismic survey equipment is typically deployed from a tender floating behind the MV Kokilmoni to minimise electronic noise from the vessel interfering with the data collection.
Food is cooked by the vessel’s crew and served in the air-conditioned dining room or out on deck.
There are 14 cabins on the MV Koklimoni