The multibeam bathymetry was acquired by the following surveys:

- Survey Name: GA-4421 MH370 Search Bathymetry Survey (Fugro Equator)/

GA-4422 MH370 Search Bathymetry Survey (Zhu Kezhen)

- Vessel Name: MV Fugro Equator/

Zhu Kezhen 872

- Institution: ATSB/Geoscience Australia

- Country: Australia

- Operator: Fugro / Chinese Navy

- Multibeam system: Kongsberg EM302/ Reson SeaBAT 8150

- Nominal sonar frequency: 30 kHz/12 kHz

- Number of beams: 288/ 234 beams

- Beamwidth across track: 1/ 2 degree

- Beamwidth along track: 1/ 2 degree

- Pulse length: variable

- Selectable depth range: 10m - 7000m

- Vessel speed: variable according to sea state.

- Start Date: 05/06/2014 // 03/06/2014

- End Date: 22/12/2014 // 31/08/2014

- Start Port: Bali/ Fremantle

- End Port: Fremantle/ Fremantle

- Grid resolution: from 25-200m

- Number of grids: 20

- Total surface coverage: 207,970 km2 (in the area of interest) & 298,165.021 Km2 (Port To Port)

- Vertical Datum: MSL

- Horizontal Datum: WGS84 UTM-47S to 50S

- Use Limitation: This dataset is not to be used for navigational purposes.

The MH370 Search bathymetry Surveys, GA-4421 GP1483 was acquired by the Australian Government through ATSB/GA onboard the MV Fugro Equator from the 05th of June to the 22th of December 2014, and GA-4422 through the Chinese Navy Vessel Zhu Kezhen 872 from the 3rd June to 31 August 2014.

The bathymetry data was delivered from the Fugro Equator as raw.all files, while the bathymetry acquired by the Zhu Kezhen was delivered as processed ASCII XYZ files.

Those two datasets were processed concurrently in Geoscience Australia by Michele Spinoccia, using CARIS HIPS & SIPS ver. 7.1.2.

1. First a vessel configuration file was created where the co-ordinates of the motion sensor and DGPS antenna and patch test offsets were recorded.

2. A new project was then created and the vessel configuration file was attached to the project file.

3. The raw swath sonar data, in raw.all format, for each line was then imported into the project and the vessel information assigned to the data.

4. The motion sensor, DGPS and heading data were then cleaned using a filter that averaged adjacent data to remove artefacts.

5. Different sound velocity profiles data for each block were attached to the corresponding raw swath sonar data files to correct the depths for changes in the speed of sound through the water column.

6. Then a new blank field area was defined that specified the geographic area of study and the co-ordinate system used. The co-ordinates for the study areas were WGS84 UTM-47S to 50S.

7. The data was cleaned by applying several filters that removed any remaining spikes in the bathymetry data using user defined threshold values. A visual inspection of the data for each line was then undertaken where artefacts and noisy data not removed by the filtering process were removed manually using Swath and subset editors modules of the Caris HIPS/SIPS software.

8. All the data for each bathymetric, motion sensor, DGPS, heading, tide and sound velocity profile data were merged to produce the final processed data file. A weighted grid of the processed data was then created for each Block.

Velocity corrections were performed to correct for different artefacts and mismatches.

Two grids were produced for each UTM zones, one for the shallow depth (high resolution) and one for the deep depth (lower resolution grid).

In UTM zones that includes both the 12 and 30 kHz we had to use the 174/200m resolution grid due to the low resolution of the 12 Khz acquisition system comparing to the 30 kHz and to avoid having gaps in the data.

9. The processed data was finally exported as grids soundings or false coloured images for presentation and reporting and as final processed data in ASCII XYZ as well as geotif formats of variable resolution.

10-The ASCII grids were then imported into ARC catalogue/info to create a raster file for each UTM zone and one of the entire survey.