ALBERT

Description: Between 30.10.2007 and 28.11.2007, bathymetric data was acquired on the continental margin of Pakistan in the Makran subduction zone during R/V METEOR cruise M74/3. This expedition builds on the findings of the previous cruise M74/2, which was dedicated to a systematic seep search in the working area, where several bubble flares, backscatter anomalies and distinct seismic records were detected by using sidescan sonar, multi-channel seismics and a sediment echosounder. These findings provided the basis for detailed surveying during the cruise M74/3. The multibeam echosounders (MBES) KONGSBERG SIMRAD EM120 and EM710 were utilized for extensive mapping of the working area, which is essential for most investigations. Furthermore, bathymetric mapping during M74/3 significantly increased the resolution of previous bathymetry grids and provided information for the deployment of the remotely operated vehicle (ROV) MARUM-QUEST. The ROV was utilized to map the seafloor, take samples at potential seep sites and deploy and recover autonomous tools, such as a bubble-meter and in-situ pore water sampler. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M74/2 cruise, the hull-mounted multibeam ecosounder (MBES) KONGSBERG SIMRAD EM710 was utilized to perform bathymetric mapping. The system is optimised to survey with high resolution in water depths of maximum 1,000 m depth and uses a frequency range from 70 to 100 kHz. 256 beams with an acoustical 1°(TX)/1°(RX) footprint are formed for each ping. Combining phase and amplitude bottom detection algorithms allows achieving best possible accuracy. For further information, consult: https://epic.awi.de/id/eprint/26726/1/Kon2007b.pdf. The position and depth of the water column is estimated for each beam by using the detected two-way-travel time and the beam angle known for each beam and taking ray bending due to refraction in the water column by sound speed into account. As most of the working area during M74/3 was deeper than 1,000m water depths, the EM710 was used sporadically as an addition to the EM120. Systematically biased outer beams produced problems in areas with large overlap of parallel profiles. The applied sound velocity profile and a roll bias were tested as possible error sources, but no significant error was found. As the effect seems to be strongest on steep slopes, it might be a problem in yaw, which was not corrected for so far. Responsible person during this cruise / PI: Markus Brüning Chief Scientist: Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/en/search/id/awi%3Adoi~10.2312%252Fcr_m74/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2007/20070155.htm

Description: Between 14.03.2006 and 25.04.2006, bathymetric data based on the KONGSBERG EM710 system (MBES) was acquired in the Gulf of Mexico during the R/V METEOR cruise M67/2. The main research goal was the investigation of asphalt volcanoes in the Campeche Bay and related sedimentary structures. The leg was split into two parts. During the first sub-leg 2a geophysical and especially hydroacoustic methods were used to explore the distribution of these asphalt volcanoes and to map knolls as well as other structures like mass wasting and asphalt flows. Using reflection seismic, sedimentary structures related to the volcanoes were also investigated. Further mapping but also sampling of vent fluids and asphalt was the research interest of sub-leg 2b. Therefore the Remotely Operating Vehicle (ROV) QUEST (Marum) as well as a TV-MUC were used. Bathymetry mapping was done using the EM120 for deeper and the EM710 for shallower regions. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M67/2 cruise, the hull-mounted multibeam echosounder (MBES) KONGSBERG EM710 was utilized to perform bathymetric mapping in shallower areas. It allows to conduct surveys in water depths of up to 2,000 m, however it operates best in shallower water depths under 500 m. Two transducer arrays transmit frequency coded acoustic signals (70 to 100 kHz). Data acquisition is based on continuous wave pulses in shallower depths and FM (chirp) pulses in greater depths. The beam footprint has a dimension of 1° by 1°. For further information on the system, consult: https://www.km.kongsberg.com/ Due to the water depth of the research area the EM120 was permanently used, while the EM710 was only used in few parts of the research area. To convert the recorded travel times into water depth, several sound velocity profiles were obtained with the shipboard CTD, providing a correction for ray bending for each beam. Depth is estimated from each beam by using the two-way travel time and the known beam angle known, and taking into account the ray bending due to refraction in the water column by sound speed variations. Responsible person during this cruise / PI: Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) Chief Scientist: : Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m67/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2006/20060077.htm

Description: Between 30.10.2007 and 28.11.2007, bathymetric data was acquired on the continental margin of Pakistan in the Makran subduction zone during R/V METEOR cruise M74/3. This expedition builds on the findings of the previous cruise M74/2, which was dedicated to a systematic seep search in the working area, where several bubble flares, backscatter anomalies and distinct seismic records were detected by using sidescan sonar, multi-channel seismics and a sediment echosounder. These findings provided the basis for detailed surveying during the cruise M74/3. The multibeam echosounders (MBES) KONGSBERG SIMRAD EM120 and EM710 were utilized for extensive mapping of the working area, which is essential for most investigations. Furthermore, bathymetric mapping during M74/3 significantly increased the resolution of previous bathymetry grids and provided information for the deployment of the remotely operated vehicle (ROV) MARUM-QUEST. The ROV was utilized to map the seafloor, take samples at potential seep sites and deploy and recover autonomous tools, such as a bubble-meter and in-situ pore water sampler. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M74/3 cruise, the hull-mounted KONGSBERG SIMRAD EM120 multibeam ecosounder (MBES) was utilized to perform bathymetric mapping. The system covers full ocean depth and transmits a nominal sounding frequency of 12 kHz. It generates 191 beams with a 1°(Tx)/2°(Rx) and a maximum opening angle of 140°. For further information consult: https://epic.awi.de/26725/1/Kon2007a.pdf The acquisition mode was set to obtain equally spaced soundings on the sea floor. Yaw movements of the ship were compensated automatically by transmitting the swath perpendicular to the track rather than to the ship's axis. The opening angle was limited by either the maximum angle possible, a maximum angle set or a maximum coverage on the sea floor. Those values were adjusted to the requirements of the special surveys in a range of 5.5 to 7 km. Where no data were available at all, the full opening angle of 140° was set. Ship speed varied between 2.5 kn and 12 kn. A sound velocity profile for the cruise was delivered during the first CTD station of the previous cruise M74/2. The depth of the water column is estimated through the two-way-travel time, beam angle and ray bending due to refraction in the water column by sound speed variations. Systematically biased outer beams produced problems in areas with large overlap of parallel profiles. The applied sound velocity profile and a roll bias were tested as possible error sources, but no significant error was found. As the effect seems to be strongest on steep slopes, it might be a problem in yaw, which was not corrected for so far. Responsible person during this cruise / PI: Markus Brüning Chief Scientist: Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/en/search/id/awi%3Adoi~10.2312%252Fcr_m74/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2007/20070155.htm

Description: Between 14.03.2006 and 25.04.2006, bathymetric data based on the KONGSBERG EM120 system (MBES) was acquired in the Gulf of Mexico during the R/V METEOR cruise M67/2. The main research goal was the investigation of asphalt volcanoes in the Campeche Bay and related sedimentary structures. The leg was split into two parts. During the first sub-leg 2a geophysical and especially hydroacoustic methods were used to explore the distribution of these asphalt volcanoes and to map knolls as well as other structures like mass wasting and asphalt flows. Using reflection seismic, sedimentary structures related to the volcanoes were also investigated. Further mapping but also sampling of vent fluids and asphalt was the research interest of sub-leg 2b. Therefore the Remotely Operating Vehicle (ROV) QUEST (Marum) as well as a TV-MUC were used. Bathymetry mapping was done using the EM120 for deeper and the EM710 for shallower regions. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M67/2 cruise, the hull-mounted multibeam echosounder (MBES) KONGSBERG EM120 was utilized to perform bathymetric mapping. It allows to conduct surveys in water depths of up to 11,000 m. Two transducer arrays transmit frequency coded acoustic signals (11.25 to 12.6 kHz). While the emission beam has a dimension of 150° across and 2° along track, the reception is obtained from 191 overlapping beams with widths of 2° across and 20° along track. The beam footprint has a dimension of 2° by 2°. For further information on the system, consult: https://www.km.kongsberg.com/ Due to the water depth of the research area the EM120 was permanently used. Only for shallower regions the EM710 was used too. To convert the recorded travel times into water depth, several sound velocity profiles were obtained with the shipboard CTD, providing a correction for ray bending for each beam. Depth is estimated from each beam by using the two-way travel time and the known beam angle known, and taking into account the ray bending due to refraction in the water column by sound speed variations. Responsible person during this cruise / PI: Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) Chief Scientist: : Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m67/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2006/20060077.htm

Description: Between 26.11.2006 and 08.12.2006, bathymetric data was acquired in the Eastern Mediterranean Sea during the R/V METEOR cruise M70/3, which was aimed at key processes at cold seeps in the Anaximander Mountains south of Turkey. The cruise addressed factors controlling fluid escape at cold seeps, precipitates and their mineral composition, the quantification of gas and gas hydrates that exist in the sediments or escape as gas bubbles into the water column, as well as seep-related ecology. The multibeam echosounder (MBES) SIMRAD EM120 was utilized to survey the working area and produce detailed bathymetric maps, specifically of the mud volcanoes. Furthermore, hydroacoustic mapping provided the basis for dive planning of the Remotely Operated Vehicle (ROV) MARUM-QUEST and flare-imaging profiles with the sub-bottom profiler PARASOUND. Further sampling was carried out with the moving lander MOVE, an Autoclave tool and several sediment coring devices. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M70/3 cruise, the hull-mounted SIMRAD 120 multibeam ecosounder (MBES) was utilized to perform bathymetric mapping, which transmits a nominal sounding frequency of 12 kHz. During the cruise, the opening angle of the multibeam echosounder was set to 140° (for one profile 150°). The 191 generated beams were set to yield an equidistant spacing on the seafloor and yaw correction was applied. For further information, contact: https://www.kongsberg.com/maritime/support/ During large scale surveys, the ship speed was 8 knots. For detailed surveying of mud volcanoes, the beam angle was adjusted to cover a swath width of about one nautical mile on the seafloor and ship speed was reduced to 5 knots. The EM120 was running during station work and ROV dives as long as it did not disturb the flare detection of the sub-bottom profiler. A sound velocity profile generated from the Levitus database was applied. The depth of the water column is estimated through the two-way-travel time, beam angle and ray bending due to refraction in the water column by sound speed variations. Responsible person during this cruise / PI: Markus Brüning Chief Scientist: Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/en/search/id/awi%3Adoi~10.2312%252Fcr_m70/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2006/20060222.htm

Description: Between 07.10.2007 and 28.10.2007, bathymetric data was acquired in the Makran region during the R/V METEOR cruise M74/2. The subduction of the Eurasian plate beneath the Arab plate in the Makran region is associated with continuous sediment input, active mud volcanism and fluid venting. The expedition was dedicated to the investigation of known seeps and the location of new venting sites. Furthermore, the scientists focused on the influence of extreme sediment thickness on the nature of vents and the relationship between local tectonics and spatial distribution of seeps. The multibeam echosounders (MBES) KONGSBERG SIMRAD EM120 and EM710 were utilized for large-scale mapping of vent-related structures on the seafloor. In order to visualize vent-related structures in the shallow subsurface, a deep-tow sidescan sonar, sediment echosounder, and high-resolution multichannel equipment were utilized. These acoustic methods were supplemented by video observations and gravity corer and multicorer samples, which yielded detailed information at many locations. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M74/2 cruise, the hull-mounted multibeam ecosounder (MBES) KONGSBERG SIMRAD EM710 was utilized to perform bathymetric mapping. The system is optimised to survey with high resolution in water depths of maximum 1,000 m depth and uses a frequency range from 70 to 100 kHz. 256 beams with an acoustical 1°(TX)/1°(RX) footprint are formed for each ping. Combining phase and amplitude bottom detection algorithms allows achieving best possible accuracy. For further information, consult: https://epic.awi.de/id/eprint/26726/1/Kon2007b.pdf. The position and depth of the water column is estimated for each beam by using the detected two-way-travel time and the beam angle known for each beam and taking ray bending due to refraction in the water column by sound speed into account. As most of the working area during M74/2 was deeper than 1,000m water depths, the EM 710 was used sporadically as an addition to the EM120. Systematically biased outer beams produced problems in areas with large overlap of parallel profiles. The applied sound velocity profile and a roll bias were tested as possible error sources, but no significant error was found. As the effect seems to be strongest on steep slopes, it might be a problem in yaw, which was not corrected for so far. Responsible person during this cruise / PI: Markus Brüning Chief Scientist: Volkhard Spiess (vspiess@uni-bremen.de) CR: https://www.tib.eu/en/search/id/awi%3Adoi~10.2312%252Fcr_m74/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2007/20080085.htm