ALBERT

Description: Acoustic direct line-of-sight distance measurements offshore Etna volcano by means of a network of five transponders. The data include travel times between all transponders, pressure, temperature (inside pressure tube), sound velocity, and inclination.

Description: Multibeam echosounder (MBES) data recorded during RV METEOR cruise M111 between 10.10.2014 and 01.11.2014 in the eastern Mediterranean Sea. The aim of the cruise was to quantify the deep geometry and architecture of the Calabria subduction zone and Ionian Sea lithosphere and to shed light on the nature of the Ionian Sea with OBS/OBH and deep sea seismics. Additionally the M111 cruise formed the core of an ambitious investigation covering the Ionian Sea and island of Sicily. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of processed data sources: During the cruise M111 the Kongsberg EM122 multibeam echosounder with a nominal sounding frequency of 12 kHz was utilized. 288 beams (and up to 864 soundings in equidistant and dual swath mode) are formed for each ping with a 1°(Tx)/2°(Rx) footprint while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult https://www.km.kongsberg.com/. The EM122 was recording during the deployment of the OBH/OBS, during seismic surveys and during transits. Responsible person during this cruise / PI: Ingo Klaucke (iklaucke@geomar.de). Chief Scientist: H. Kopp hkopp@geomar.de CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m111/ CSR: http://www.bsh.de/aktdat/dod/fahrtergebnis/2014/20140277.htm Responsible person for data delivery and approval: Paul Wintersteller (seafloor-imaging@marum.de) A special thanks goes to to the watch keeper during M111: Marzia Rovere, Ingo Klaucke, Anne Krabbenhoeft, Marc-André Gutscher

Description: During RV Meteor cruise M111 refraction and wide-angle reflection seismic data were acquired. We present eight seismic record sections (.sgy format) of the hydrophone components from four ocean bottom hydrophones (OBH501, OBH503, OBH505, OBH507) and four ocean bottom seismometers (OBS502, OBS504, OBS506, OBS508) along the NNE-SSW oriented seismic profile DY-05, which is situated in the Ionian Abyssal Plain. The profile stretches over a distance of 131 km and was shot using an airgun array of six G-gun clusters with a total volume of 84 l (5440 cu in) at 210 bar. A total of 946 shots were fired every 60 s (~140 m) with an airgun towed behind the vessel in a depth of 8 m. Data are unprocessed, however, they are corrected for instrument drift along the profile using the symmetry of the direct arrival and the data are time corrected.

Description: During RV Maria S. Merian cruise MSM71 refraction and wide-angle reflection seismic data were acquired. We present profile P02 consisting of 15 seismic record sections (seg-y format) of the hydrophone components from three ocean bottom hydrophones (OBH204, OBH208, OBH212) and twelf ocean bottom seismometers (OBS201 - OBS203, OBS205-OBS207, OBS209-OBS211, OBS213-OBS215) along the SW-NE oriented seismic profile MSM71-P02, which is situated in the centre of the Ligurian Basin. The profile stretches over a distance of 127 km and was shot using an airgun array of six G-gun clusters with a total volume of 84 l (5440 cu in) at 190 bar. A total of 1079 shots were fired every 60 s (~123 m) with an airgun towed behind the vessel in a depth of 8 m. Data are unprocessed, however, they are corrected for instrument drift along the profile using the symmetry of the direct arrival and the data are time corrected.

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: Upper-ocean velocities along the cruise track of Sonne cruise SO288 were continuously collected by a vessel-mounted Teledyne RD Instruments 75 kHz Ocean Surveyor ADCP. The transducer was located at 6.0 m below the water line. The instrument was operated in narrowband mode with 8 m bins and a blanking distance of 8.0 m, while 100 bins were recorded using a pulse of 1.45 s. The ship's velocity was calculated from position fixes obtained by the Global Positioning System (GPS). Heading, pitch and roll data from the ship's gyro platforms and the navigation data were used by the data acquisition software VmDas internally to convert ADCP velocities into earth coordinates. Accuracy of the ADCP velocities mainly depends on the quality of the position fixes and the ship's heading data. Further errors stem from a misalignment of the transducer with the ship's centerline. Data post-processing included water track calibration of the misalignment angle (-0.04° +/- 1.1923°) and scale factor (1.0023 +/- 0.0230) of the Ocean Surveyor signal. The average interval was set to 120 s. Velocity quality flagging is based on following threshold criteria: abs(UC) or abs(VC) 〉 1.5 m/s, rms(UC_z) or rms(VC_z) 〉 0.3.

Description: Underway temperature and salinity data was collected along the cruise track with two autonomous measurement systems, called self-cleaning monitoring boxes (SMBs). Usually, the SMBs are changed after ~12 hours. While temperature is taken at the water inlet in about 4 m depth, salinity is estimated within the SMB from conductivity and interior temperature. No temperature and salinity calibration were performed. For details to all processing steps see Data Processing Report.