MH370 Search Phase 1 Backscatter grids (GA-4421)

Brief description

On behalf of Australia, and in support of the Malaysian accident investigation, the Australian Transport Safety Bureau (ATSB) was leading search operations for missing Malaysian airlines flight MH370 in the Southern Indian Ocean. Geoscience Australia provided advice, expertise and support to the ATSB to facilitate bathymetric surveys, which were undertaken to provide a detailed map of the sea floor topography to aid navigation during the underwater search. Prior to the bathymetric survey, very little was known about the sea floor in the MH370 search area, as few marine surveys have taken place in the area. Existing maps of the sea floor were coarse, having been derived from satellites and only providing a general indication of water depth. Before the underwater search for MH370 could begin, it was necessary to accurately map the sea floor to ensure that the search is undertaken safely and effectively. Bathymetry survey vessels spent months at sea, scanning the sea floor with multibeam sonar to gather detailed, high-resolution data. The multibeam backscatter data was acquired from Fugro Equator between June 2014 and February 2017 were processed by Geoscience Australia to 30 m resolution. This backscatter data was processed for the search area only, excluding all transit data and vessel turns. The data is presented as a yellow to bronze colour ramp, with high backscatter values in darker shades and overlain on a hillshade created from the 150 m bathymetry data. The hillshade was created with the parameters of point illumination azimuth at 45 degrees and altitude of 45 degrees.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: The multibeam backscatter data was acquired from Fugro Equator between June 2014 and February 2017 and were processed by Geoscience Australia to 30 m resolution. Backscatter data was processed for the search area only, excluded all transit data and vessel turns. CARIS HIPS and SIPS version 7.1.2. was used to process backscatter data. The fully processed backscatter strengths were corrected for transmission loss, insonification area and slope using Geocoder in CARIS. The grid values are the average values of the processed backscatter point data within each 30 m grid cell. Backscatter mosaics were created to 30 m resolution. Backscatter grids have been rendered over a yellow to bronze scale colour-ramp with minimum and maximum decibel values being -50 and -20 dB respectively, with high backscatter values in darker shades. Processing software: CARIS HIPS & SIPS 7.1.2 SP2 Survey Name: GA-4421 MH370 Search Bathymetry Survey (Fugro Equator) Vessel: MV Fugro Equator Country: Australia Operator: Fugro Bathymetric system used: Kongsberg EM302 Nominal sonar frequency: 30 kHz Number of beams: 288 Beamwidth across track: 1 degrees Beamwidth along track : 1 degrees Pulse length: Variable Depth range: 10 m - 7000 m Vessel speed: variable according to sea state Start date of survey: 05/06/2014 End date of survey: 05/02/2017 Institution: Geoscience Australia Start port: Bali End port: Fremantle Data processed by: Justy Siwabessy, Maggie Tran Grids resolution: 30m Vertical Datum: MSL Horizontal Datum: WGS84 UTM-45S to WGS84 UTM-47S Use Limitation: This dataset is not to be used for navigational purposes.