DOI: 10.1594/pangaea.860486
title: Gridded bathymetry from multibeam echosounder EM122 data of the cruise MSM34/2 (2013)

description: Bathymetry based on data recorded during MSM34-2 between 27.12.2013 and 18.01.2014 in the Black Sea. The main objective of this cruise was the mapping and imaging of the gas hydrate distribution and gas accumulations as well as possible gas migration pathways.Objectives of Cruise:Gas hydrates have been the focus of scientific and economic interest for the past 15-20 years, mainly because the amount of carbon stored in gas hydrates is much greater than in other carbon reservoirs. Several countries including Japan, Korea and India have launched vast reasearch programmes dedicated to the exploration for gas hydrate resources and ultimately the exploitation of the gas hydrates for methane. The German SUGAR project that is financed the the Ministry of Education and Research (BmBF) and the Ministry of Economics (BmWi) aims at developing technology to exploit gas hydrate resources by injecting and storing CO2 instead of methane in the hydrates. This approach includes techniques to locate and quantify hydrate reservoirs, drill into the reservoir, extract methane from the hydrates by replacing it with CO2, and monitor the thus formed CO2-hydrate reservoir. Numerical modeling has shown that any exploitation of the gas hydrates can only be succesful, if sufficient hydrate resources are present within permeable reservoirs such as sandy or gravelly deposits. The ultimate goal of the SUGAR project being a field test of the technology developed within the project, knowledge of a suitable test site becomes crucial. Within European waters only the Norwegian margin and the Danube deep-sea fan show clear geophysical evidence for large gas hydrate accumulations, but only the Danube deep-sea fan most likely contains gas hydrates within sandy deposits. The main objective of cruise MSM34 therefore is locating and characterising suitable gas hydrate deposits on the Danube deep-sea fan.
description: During the MSM34-2 cruise the Kongsberg EM122 multi-beam echo-sounder was used. The EM122 uses a nominal sounding frequency of 12 kHz. 288 beams or 432 soundings, with a 2°/2° footprint are formed for each ping while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult https://www.km.kongsberg.com/. Based on the observations during MSM34-1 the bathymetry of MSM34-2 mainly consists of the detailed mapping to the gas hydrate distribution area. Responsible person during this cruise / PI: Jasper Hoffmann (jhoffmann@geomar.de), Felix Gross (GEOMAR), Joerg Bialas (GEOMAR) Description of data processing:Postprocessing and products were conducted by the Seafloor-Imaging group of MARUM, responsible person: Paul Wintersteller (seafloor-imaging@marum.de). The open source software MB-system (Caress, D.W., and D.N. Chayes, MB-System Version 5, Open source software distributed from the MBARI and L-DEO web sites, 2000-2012.) was utilized for this purpose. A tide correction was applied, based on the Oregon State University (OSU) tidal prediction software (OTPS) that is retrievable through MB-System. In general, there is a tide differences of less than 20 cm in the Black Sea. Further roll, pitch, heave and SVP corrections were not applied for the MSM34-2 data. Bathymetric data has been manually cleaned for existing artefacts with mbeditviz. NetCDF (GMT) grids of the product and the statistics were created using mbgrid. Quality assurance was furthermore proven by visual and statistical comparison of crossing survey-lines from different cruises throughout the Black Sea. No total propagated uncertainty (TPU) has been calculated to gather vertical or horizontal accuracy. The currently published bathymetric grid of the cruise has a resolution of 125 m. A higher resolution is, at least partly, achievable.