ALBERT

Description: High-resolution 3D seismic refraction data during research cruise MSM63 in April/May 2017 onboard RV Maria S. Merian. 15 ocean bottom seismometers sampled seismic shots around the Scanner Pockmark, central North Sea. Seismic data are in standard segy-format.

Description: Source data of the North Sea well inventory: United Kingdom (UK)- Oil and Gas Authority (Dec. 2018) - https://data-ogauthority.opendata.arcgis.com/datasets/oga-wells-ed50 Contains information provided by the OGA. Wells are extracted for the area of the PGS data set PGS Mega Survey Plus. We measured the distance between all wells of the test group (n = 43) and all those who are within the seismic data set (n = 1,792; presented here) and their closest bright spot with polarity reversal. Furthermore, we calculated the mean RMS amplitudes and RMS amplitude standard deviation for a buffer radius of 300 m around the well paths for all wells inside the seismic data set and the visited wells as 300 m is the distance below which all of the visited wells of the test group showed gas release in form of flares from the seafloor. We test, if the propensity of a well to leak can be identified by using a logistic regression, which includes regressors such as well activity data and/or derived parameters such as mean RMS amplitude and mean RMS amplitude standard deviation, the distance towards the most proximal bright spot with polarity reversal and age (spud date). In order to identify the most suitable regressor combination best subset selection is employed. The main selection criterion chosen was the prediction accuracy from randomly and repeatedly splitting the visited wells into a training and a test set and then using the fitted logistic regression to predict the test data. The most suitable subset turns out to only employ the distance to polarity reversal, producing a prediction accuracy of 89% and the following logistic regression results: In order to obtain confidence intervals using the normal distribution the distance to bright spot with polarity reversal has to be normally distributed, which it is not. Yet it can be transformed to normality by adding 100 meters to the original distance and then taking the natural logarithm: Logistic regression fit for leakage of all visited wells using distance to bright spot with polarity reversal in meters as a regressor. Please find further information on the applied statistical analyses in the supplementary material. EstimateStd. Errorz valuePr(〉|z|)Significance Intercept4,853.9461,735.1282.7970.005150.01 Distance−0.0073610.002700−2.7260.006400.01 The transformed logistic regression model is then used to predict the probabilities of leakage for the wells within our seismic data set in the Central North Sea (here presented data). In order to obtain confidence bands this logistic regression is performed subtracting and adding two standard deviations from the calculated probability. The point estimate predicts leakage from 926 of the 1,792 wells, where the 95% confidence interval ranges from 719 to 1,058.

Description: This 2D multi-channel seismic dataset was acquired during SONNE cruise SO252 offshore Ritter Island, Papua New Guinea in November/December 2016. The dataset contains 680 km of normal-moveout-corrected and stacked vertical seismic profiles. Aim of the seismic experiment was to map and image the deposit of the 1888 Ritter Island Sector Collapse. The data was collected with a 250 m-long (160 channels) streamer system with a group spacing of 1.56 m. The system consisted of twenty 12.5 m-long active sections, a 25 m-long vibro-stretch section and 60 m-long tow cable. As seismic source, two GI airguns, shot in harmonic mode (105/105 cubic inch) were used. The data were processed with a 10, 45, 250, 400 Hz bandpass filter and a normal moveout correction (constant velocity: 1495 m/s). Detailed information on the data acquisition can be found in the SO252 cruise report (https://doi.org/10.3289/CR_SO252).

Description: During research cruise POS538, 2D seismic reflection data were collected onboard research vessel FS POSEIDON in November 2019. The profiles cover the Santorini caldera and the neighboring basins around Santorini. Some profiles were used as side survey data for IODP expedition 398 and will only be available after the IODP embargo period. The dataset consists of SEGY files with UTM coordinates stored in bytes 73 and 77 and shot points stored in byte 5. The coordinate system is UTM35 WGS84. Multi-channel seismic data of cruise POS538 were acquired with a high lateral resolution (CMP spacing of ~1.56 m). As a seismic source, we used a GI-pulser that was operated in harmonic mode with primary and secondary volumes of 45 in3. Seismic energy was recorded by multiple concatenated Geometrics GeoEel streamer segments, resulting in active streamer sections ranging from 190 m to 250 m in length. Processing comprised trace-editing, simple frequency filtering (15-1500 Hz), and multiple suppression by means of surface-related multiple elimination (SRME). This was followed by spherical divergence correction, time-variant frequency filtering, pre-stack time migration, top-muting, and white-noise removal. With a main frequency of 125 Hz, the vertical resolution can be approximated to approx. 4-8 m. For more information, see the cruise report (doi:10.3289/cr_pos538).

Description: Included here are 3D post-stack time migrated data from the Kolumbo Volcano in the Aegean Sea. The data were collected aboard RV Poseidon in 2019 during Research Cruise POS538 using GEOMAR's P-Cable seismic system. Seismic source was a Generator-Injector airgun fired in harmonic mode with generator and injector volumes of 45 cubic inches. The source was towed at a nominal depth of 2 m beneath the sea surface. Shot interval was 4 seconds at a ship speed of ~3.5 knots. Gun pressure was set at 200 bar. The receiver geometry consisted of 16 streamer sections attached to a 199 m long cross cable. Processing included: 3D geometry application, trace editing, static time corrections, anomalous amplitude attenuation, FK filtering, pre-stack trace interpolation, adaptive subtraction multiple suppression using a 1D pattern matching algorithm, sorting to common midpoint gathers, normal moveout correction (1517 m/s constant velocity), stacking, trace interpolation, 3D FK coherency filtering, 3D Stolt migration (1517 m/s constant velocity), residual 2D finite difference migration (first inline, then crossline). The dataset has a horizontal resolution of 3.125 m (bin size) and a dominant frequency of ~100 Hz. Acquisition and processing details are included in the EBCDIC header of the SEG-Y file.

Description: Multibeam bathymetry raw data was recorded in the North Atlantic during cruise MSM78 that took place between 2018-10-16 and 2018-10-25. The data was collected using the ship's own Kongsberg EM 712. This data is part of the DAM (German Marine Research Alliance) underway research data project. Sound velocity profiles (SVP) were applied on the data for calibration. SVP data are part of this dataset publication.

Description: During research cruise M87/2 COSY, Parasound echosounder data were collected onboard research vessel FS Meteor in May 2012. The profiles cover the northern sidewall of the Storegga Slide and the Nyegga pockmark field at the mid-Norwegian Margin. The uploaded dataset is converted to the SEGY data format, coordinates are stored in the bytes 73 and 77 in UTM-cm and the shot points are stored in byte 5. The coordinate system is UTM31 WGS84. For more information, see the cruise report (doi:10.2312/cr_m87_2).