ALBERT

Description: The backscatter data were collected during R/V SONNE Cruise SO244. For processing of the backscatter information, all data recorded during turns of the ship were eliminated before gridding to a 20 m cell size throughout the study area.

Description: The submerged North Anatolian Fault in the Sea of Marmara is lacking any major seismic activity since its last rupture in 1766. The purpose of this acoustic ranging experiment was to determine whether this fault is continuously and aseismically creeping (i.e. slipping) or whether it is locked and thus accumulating stress that could cause a large magnitude earthquake, few tens of kilometers away from Istanbul. In October 2014, a ranging network of 10 acoustic transponders was installed across an active segment of the North-Anatolian Fault in the Marmara Sea at a depth of about 800 m (Figures 1 and 2, see further details). Figure 1: Map showing the location of the geodetic network in the Sea of Marmara (yellow box). Local ocean bottom seismometer (OBS) stations (29/10/2014-25/04/2015 and 26/04/2015-13/04/2016) are indicated with black triangles. Bathymetry in the central Sea of Marmara from Le Pichon et al. (2001) (https://doi.org/10.1016/S0012-821X(01)00449-6) and topography from Ryan et al. (2009) (https://doi.org/10.1029/2008GC002332). Figure 2: Map showing the location of the geodetic stations (red points indicate geodetic transponders from GEOMAR labelled with transponder IDs and green points indicate the French transponders). Bathymetry from AUV mapping (Grall et al. 2018, https://doi.org/10.17882/55744). Baselines of the intercommunicating transponders of Geomar shown with lines. The black baseline (G2302-G2307) has no line of sight. The long baselines with lengths of larger than 1000 m (shown in orange) are configured to work only unidirectional. White lines show bidirectional baselines. Figure taken from cruise report of POS484 (https://doi.org/10.3289/CR_POS_484/1). The acoustic network comprised 4 transponders from the University of Brest, France, and 6 transponders from GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany. The data available through this web site correspond to the data collected by the 6 German stations of GEOMAR's GeoSEA Array only. Data and details of the 4 French stations are accessible here: https://www.seanoe.org/data/00486/59750/ Data from the GeoSEA Array available here include sets of acoustic ranging between pairs of stations (i.e. two-way-travel times), in addition to sound-speed, temperature and pressure measurements at each station. Sample rate was 120 minutes during the 2.5 years of data availability. These are the raw, unprocessed data. For instance, distances must be inferred from two-way-travel times and sound-speeds. Deployment and data upload cruises: - Stations were installed during the MARSITE cruise, leg1 (from 28/10 to 01/11 2014) with RV Pourquoi Pas? (https://doi.org/10.17600/14000500). - First data download and visual inspection of the transponders with ROV were made during the MARSITE cruise, leg3 (13 to 16 November 2014). - In April 2015, the data were acoustically downloaded from the seafloor transponders using a modem from the sea surface during RV Poseidon cruise POS484 (https://doi.org/10.3289/CR_POS_484/1). - In April 2016, the data were again downloaded during RV Poseidon cruise POS497 (https://doi.org/10.3289/CR_POS_497). - In May 2017, a third set of acoustic ranging data was downloaded with RV Yunus (cruise YUNUS17). - In January 2018, a download was attempted with RV Yunus (cruise YUNUS18), but the German transponders did not respond, most likely due to empty batteries of the transponders on the seafloor. Three of the French instruments responded which had larger batteries, and two were retrieved from the seafloor because their batteries were almost exhausted. Details on the Sonardyne transponders and user manuals of the 6TD autonomous monitoring system can be found here: https://www.sonardyne.com/product/autonomous-monitoring-system/

Description: We provide a catalog of microseismicity recorded during a 32-days long deployment of ocean bottom seismometer (OBS) at the southern Fonualei Rift and Spreading Center in the Lau Basin, southwestern Pacific.

Description: Multibeam bathymetric data were acquired during R/V SONNE Cruises SO104, SO244, and R/V Marcus G. Langseth Cruise MGL1610. The datasets were individually processed and gridded with grid cell sizes of 75 m. For the combined grid, depth information from SO244 was used wherever possible. If no SO244 data were available, MGL1610 data were preferred over SO104 data. The backscatter data were collected during R/V SONNE Cruise SO244. For processing of the backscatter information, all data recorded during turns of the ship were eliminated before gridding to a 20 m cell size throughout the study area.

Description: Multibeam bathymetry raw data was recorded in the Pacific during cruise SO267 that took place between 2018-12-11 and 2019-01-26. The data was collected using the ship's own Kongsberg EM 122. Sound velocity profiles (SVP) were applied on the data for calibration. SVP data are part of this dataset publication. This data is part of the DAM (German Marine Research Alliance) underway research data project.

Description: The dataset comprises measurements of the total intensity of the magnetic field measured with a towed Overhauser sensor and calculated magnetic anomalies. The data were measured along a E-W trending profile at ~16°S in the northern Lau Basin and were acquired in January 2019 as part of the SO267 cruise.

Description: This dataset includes earthuake location results from a 32-days long Ocean Bottom Seismometer (OBS) experiment conducted at the southern end of the Fonualei Rift and Spreading Center in the Lau Basin, southwestern Pacific. The experiment was conducted during RV Sonne cruise SO267, project ARCHIMEDES I. The accompanying zip-file "SEISAN_files.zip" includes raw waveform data for all earthquakes and the file "select.out" that includes all manual phase onset picks of all earthquakes. All data in the zipped archive "SEISAN_files.zip" may be processed and used with the SEISAN seismology software.

Description: The dataset contains ocean bottom hydrophone data acquired on profile P02 during RV Sonne Expedition SO267 (project ARCHIMEDES I) to the Lau Basin, Southwestern Pacific. 27 OBS recorded the seismic survey successfully and returned data for the two consecutively performed acquisitions, once with a 50m shot interval and once with a 170m shot interval. The stations 207, 215 and 229 suffered from recorder errors, which prevented or interfered with the redording of data and thus their analysis.

Description: The Atlas PARASOUND P70 system was used to acquire high resolution sub-bottom profiler data throughout most of the cruise. Two different waves with frequencies of ~18-20 kHz (primary high frequency, PHF) and a ~22-24 kHz wave were used to create a so-called secondary high (about 40-42 kHz, SHF) and a secondary low frequency (SLF) of about 4 kHz, which is used for the sub-bottom profiling. The opening angle of the transducer array is 4° by 5°, which corresponds to a footprint size of about 7 % of the water depth. Data was acquired along p02 of Sonne cruise SO267 which crosses the northern Fonualei Rift Spreading Centre and the southern Mangatolu Triple Junction about ~16° S.

Description: Reflection seismic data from cruise SO267 (ARCHIMEDES I), profile BGR18-202. Data acquistion during January 2019 (Station SO267_81-1) using a 312 channel Sentinel RD streamer (3900 m active length) and a 12 G-Gun array (84 liters). Processing up to prestack depth migration.