Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Maria S. Merian	MSM100	11.05.2021 - 09.06.2021		North Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Ehrhardt Axel	Bundesanstalt fur Geowissenschaften und Rohstoffe, Hannover	Emden	Emden

Ziel der Reise / Objectives of Cruise:

Objectives: Within the transition to renewable energy, the integrity of barriers and seals in the deep underground becomes increasingly important for storage purposes, e.g. for CO2 in the framework of CCS or for synthetic energy gases in the course of the change to renewable energy. The tasks of this project are exemplary studies on the integrity of barrier formations of Cenozoic shale layers in the German North Sea. If the barrier formation is not closed, either because of abandoned drill holes or along natural pathways it enables discharge of fluids into the North Sea. Thus, the second topic is the understanding of migration of fluids along pathways through seal formations. For the first time we will use high resolution 3D seismic and OBS data to image the Cenozoic sediments in detail. By means of the high resolution data we will image fault systems that were previously postulated in the "sub-seismic" domain. The data will cover in close proximity different fault systems and undisturbed strata. The outcome of this study will be a profound understanding of fault systems and structures in the Cenozoic sediments like polygonal-, crestal- as well as tunnel valleys and especially how they communicate. Such a study on potential seal bypass systems is missing so far in the German North Sea. Narrative: On May 11th 2021 the scientific/technical party of MSM100 embarked on the Research Vessel Maria S. Merian. All scientists and technicians were tested negative. We used May 11th and 12th to mobilize all the heavy equipment, while being in the port of Emden. On Wednesday, May 12th evening we left the port of Emden and sailed towards the research area. After the arrival in the research area in the morning of May 13th we started deploying "click-detectors" in the framework of a common project with the Stiftung Deutsches Meeresmuseum. After that we started the deployment of 12 Ocean Bottom Seismometers (OBS). Because of the obligation to remove everything after finishing the survey, the anchors of the OBS were connected with a rope to the OBS. After all OBS were deployed, we started handling tests of the paravans. During the night, we acquired Parasound sediment echosounder profiles. On May 14th we started to deploy the 3D seismic equipment. Because of a defect bird on the port side streamer cable and issues with the power line to the tail buoy, we had to retrieve the port side equipment again at the evening. During the night, the starboard equipment stayed deployed and Parasound data was collected. On May 15th the bird and the power line were fixed and the port side equipment was deployed. At noon we started with the first sail line of the 3D seismic survey. From May 16th to May 20th we acquired 3D seismic data. We observed a bad weather period on the weather forecast with high wind speeds (8 – 9 Bft) and high swell and wind sea (up to 2.8 m), so we decided to retrieve the entire equipment on May 20th at 13:00 LT. During the bad weather window from May 20th to May 24th we switched to 2D seismic data acquisition and acquired 18 2D seismic lines. In order to test the new OBS anchor system we released and picked up two OBS successfully. On May 25th we switched back to 3D. From May 25th to June 5th we acquired 3D data. A 5.2 x 18 km box was completely covered. On June 5th we retrieved the 3D seismic equipment. During June 6th we released the 10 remaining OBS. One OBS did not surface. During the night, we localized the OBS by means of the EM712 with an accuracy of about 1 m. The crew of RV Maria S. Merian assembled a provisory dredge and successfully dredged the missing OBS on June 7th. After all OBS were back on board we used the June 7th and 8th to start the demob. On Wed. June 9th we met the pilot at the rendezvous position and headed towards Emden. Here we finished the demobilization of our equipment and the gravity land closure measurement was done. At 15:00 LT the scientific/technical party disembarked from RV Maria

Messungen / Measurements