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  • 2020-2024  (103)
  • 1980-1984
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  • 2022  (103)
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  • 1
    Publication Date: 2024-02-15
    Description: Hydraulic fracturing (HF) operations are widely associated with induced seismicity in the Western Canadian Sedimentary Basin. This study correlates injection parameters of 12,903 HF stages in the Kiskatinaw area in northeast British Columbia with an enhanced catalog containing 40,046 earthquakes using a supervised machine learning approach. It identifies relevant combinations of geological and operational parameters related to individual HF stages in efforts to decipher fault activation mechanisms. Our results suggest that stages targeting specific geological units (here, the Lower Montney formation) are more likely to induce an earthquake. Additional parameters positively correlated with earthquake likelihood include target formation thickness, injection volume, and completion date. Furthermore, the COVID‐19 lockdown may have reduced the potential cumulative effect of HF operations. Our results demonstrate the value of machine learning approaches for implementation as guidance tools that help facilitate safe development of unconventional energy technologies.
    Description: Plain Language Summary: Hydraulic fracturing (HF), a technique used in unconventional energy production, increases rock permeability to enhance fluid movement. Its use has led to an unprecedented increase of associated earthquakes in the Western Canadian Sedimentary Basin in the last decade, among other regions. Numerous studies have investigated the relationship between induced earthquakes and HF operations, but the connection between specific geological and operational parameters and earthquake occurrence is only partly understood. Here, we use a supervised machine learning approach with publicly available injection data from the British Columbia Oil and Gas Commission to identify influential HF parameters for increasing the likelihood of a specific operation inducing an earthquake. We find that geological parameters, such as the target formation and its thickness, are most influential. A small number of operational parameters are also important, such as the injected fluid volume and the operation date. Our findings demonstrate an approach with the potential to develop tools to help enable the continued development of alternative energy technology. They also emphasize the need for public access to operational data to estimate and reduce the hazard and associated risk of induced seismicity.
    Description: Key Points: We use supervised machine learning to investigate the relationship between hydraulic fracturing operation parameters and induced seismicity. Geological properties and a limited number of operational parameters predominantly influence the probability of an induced earthquake. The approach has the potential to guide detailed investigations of injection parameters critical for inducing earthquakes.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Gouvernement du Canada Natural Sciences and Engineering Research Council of Canada http://dx.doi.org/10.13039/501100000038
    Description: https://doi.org/10.5281/zenodo.5501399
    Description: https://ds.iris.edu/gmap/XL
    Description: https://files.bcogc.ca/thinclient/
    Description: https://open.canada.ca/data/en/dataset/7f245e4d-76c2-4caa-951a-45d1d2051333
    Description: https://github.com/obspy/obspy
    Description: https://github.com/eqcorrscan/EQcorrscan
    Description: https://github.com/smousavi05/EQTransformer
    Description: https://github.com/Dal-mzhang/REAL
    Description: https://scikit-learn.org/stable/
    Description: https://docs.fast.ai/
    Description: https://xgboost.readthedocs.io/en/stable/
    Description: https://github.com/slundberg/shap
    Description: https://docs.generic-mapping-tools.org/latest/
    Keywords: ddc:551.22 ; induced seismicity ; machine learning ; hydraulic fracturing
    Language: English
    Type: doc-type:article
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  • 2
    Publication Date: 2023-06-21
    Description: Individual species were identified and 550 individuals per species were picked from the 〉250 µm fraction under dissecting microscope for each sample. Approximately 7 mg of picked and identified foraminifera shells were crushed between glass microscope slides and rinsed with MilliQ water. Samples were cleaned prior to δ¹⁵NFB measurement as described in Marcks et al., (2023). Once samples were clean, organic nitrogen was released into solution by acid dissolution of the foraminiferal calcite. Samples were acidified prior to measurement. Nitrate concentrations were measured by chemiluminescence on a Teledyne Instruments (Model 200E) chemiluminescence NO/NOx analyzer. δ15NFB samples, 10 nmol in size, were measured by bacterial conversion of nitrate to nitrous oxide, with measurement of the δ¹⁵N of the nitrous oxide by automated extraction and gas chromatography-isotope ratio mass spectrometry on a Thermo Delta V Plus IRMS. The potassium nitrate reference materials IAEA-N3 and USGS 34 (+4.7 ‰ and 1.8 ‰, respectively) were used to standardize results (Gonfiantini et al., 1995). Note, testing of a subset of 6 samples, each with full procedural triplicates, for a total of 18 samples, showed negligible differences in nitrogen content and δ¹⁵NFB values with and without a reductive cleaning step, and so it was omitted here to avoid unnecessary loss of sample material. Sample replicates and triplicates were analyzed when possible. Full procedural replicates were analyzed for 134 sample splits, representing 66 unique samples, when enough foraminifera were available for duplicate or triplicate analysis. The average standard deviation of procedural replicates is 0.4 ‰. Full operational blanks and amino acid standards (USGS 65 glycine) were measured in each batch. The average standard deviation of glycine standards measured in triplicate is 0.3 ‰. We estimated the δ¹⁵N value of the persulfate blank using a dilution series (5, 7.5, 10, and 20 μM of the glycine standard and the fraction of the blank in standards. We applied a blank correction to each sample based on the calculated mean δ¹⁵N value of all of the persulfate blanks for the dataset and the fraction of the blank in the N content of each sample. Data were subset to exclude N content outliers (〉2 s.d. from mean and where the blank was greater than 20 % of the sample N content, with significantly different δ¹⁵N values from other replicates). Full propagated analytical error associated with measurement and blank correction, following Higgins et al., (2009, doi:10.1021/ac8017185 ), was on average 0.6 ‰. Propagating the errors, including not only the procedural replicates and their variance, but the relative size of the blanks, the mean of the calculated blank δ¹⁵N values (5± 10 ‰). The mean value, 0.6 ‰, is used where procedural replicates were limited by sample availability. The age model is based on the benthic oxygen isotope stratigraphy presented by Starr et al. (2021, doi:10.1038/s41586-020-03094-7). This age model for Site 361-U1475 was generated with 12 radiocarbon dates and 33 benthic oxygen isotope tie points which were graphically aligned with a probabilistic stack of 180 globally distributed benthic oxygen isotope records (Starr et al., 2021, doi:10.1038/s41586-020-03094-7).
    Keywords: Agulhas Plateau; biogenic silica; Foraminifera-bound nitrogen isotopes; G. bulloides; G. inflata; mid-Pleistocene transition; N. pachyderma; opal; Subtropical Front
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 3
    Publication Date: 2024-03-08
    Description: GTS-12 timescale adjusted age models for ODP site 1263 with biostratigraphic (calcareous nannoplankton and foraminifer), magnetostratigraphic datums and cyclostratigraphic alignments.
    Keywords: 208-1263A; 208-1263B; 208-1263C; 208-1263D; Age; Age model, Gradstein et al. (2012) GTS2012; age models; Ageprofile Datum Description; Ageprofile Datum Type; biostratigraphy; Comment; Cyclostratigraphy; Depth, bottom/max; Depth, composite; Depth, composite bottom; Depth, composite top; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; GTS12; Joides Resolution; Leg208; Magnetostratigraphy; Ocean Drilling Program; ODP; Reference/source; Sample code/label; Walvis Ridge, Southeast Atlantic Ocean
    Type: Dataset
    Format: text/tab-separated-values, 1036 data points
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  • 4
    Publication Date: 2024-02-02
    Description: LADCP measurements from METEOR cruise M159 used a two-instrument configuration with two Teledyne RDI 300 kHz workhorse ADCPs mounted in down- and up-looking positions. Data collection and processing was performed according to recommendations in the GO-SHIP manual (Thurnherr et al., 2010).
    Keywords: Calculated; CTD/Rosette; CTD 001; CTD 002; CTD 003; CTD 004; CTD 005; CTD 006; CTD 007; CTD 008; CTD 009; CTD 010; CTD 011; CTD 012; CTD 013; CTD 014; CTD 015; CTD 017; CTD 018; CTD 019; CTD 020; CTD 021; CTD 022; CTD 023; CTD 024; CTD 025; CTD 026; CTD 027; CTD 028; CTD 029; CTD 030; CTD 031; CTD 032; CTD 033; CTD 034; CTD 035; CTD 036; CTD 037; CTD 038; CTD 039; CTD 040; CTD 041; CTD 042; CTD 043; CTD 044; CTD 045; CTD 046; CTD 047; CTD 048; CTD 049; CTD 050; CTD 051; CTD 052; CTD 053; CTD 054; CTD 055; CTD 057; CTD 058; CTD 059; CTD 060; CTD 061; CTD 062; CTD 063; CTD 064; CTD 065; CTD 066; CTD-RO; Current velocity, east-west; Current velocity, north-south; Date/Time of event; DEPTH, water; Error, absolute; Event label; Latitude of event; Longitude of event; Lowered Acoustic Doppler Current Profiler (LADCP); M159; M159_1-1; M159_11-1; M159_12-1; M159_13-1; M159_14-1; M159_15-1; M159_18-1; M159_19-1; M159_20-1; M159_23-1; M159_24-1; M159_27-1; M159_28-1; M159_29-1; M159_30-1; M159_31-1; M159_32-1; M159_33-1; M159_34-1; M159_35-1; M159_36-1; M159_37-1; M159_38-1; M159_39-1; M159_40-1; M159_4-1; M159_41-1; M159_42-1; M159_43-1; M159_44-1; M159_45-1; M159_46-1; M159_47-1; M159_48-1; M159_49-1; M159_50-1; M159_5-1; M159_51-1; M159_52-1; M159_53-1; M159_54-1; M159_55-1; M159_56-1; M159_57-1; M159_58-1; M159_59-1; M159_60-1; M159_6-1; M159_61-1; M159_62-1; M159_63-1; M159_64-1; M159_65-1; M159_66-1; M159_67-1; M159_68-1; M159_69-1; M159_70-1; M159_7-1; M159_71-1; M159_72-1; M159_73-1; M159_74-1; M159_75-1; Meteor (1986); RACE-II; Regional Atlantic Circulation and global Change II
    Type: Dataset
    Format: text/tab-separated-values, 64644 data points
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  • 5
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from the thermosalinograph [TSG] instrument acquiring continuously during the full course of the campaign. Surface seawater was pumped continuously through a hull inlet located 1.5 m under the waterline using a membrane pump (10 LPM; Shurflo), circulated through a vortex debubbler, a flow meter, and distributed to a number of flow-through instruments. A thermosalinograph [TSG] (SeaBird Electronics SBE45/SBE38), measured temperature, conductivity, and thus salinity. Salinity measurements where intercalibrated against unfiltered seawater samples [SAL] taken every week from the surface ocean, and corrected for any observed bias. Moreover, temperature and salinity measurements were validated against Argo floats data collocated with Tara.
    Keywords: CTD, Sea-Bird, SBE45/SBE38; DATE/TIME; Fondation Tara Expeditions; FondTara; LATITUDE; LONGITUDE; Pacific Ocean; Salinity; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; Temperature; Temperature, water; UMS; Underway, multiple sensors
    Type: Dataset
    Format: text/tab-separated-values, 1770033 data points
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  • 6
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from an optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) instrument acquiring continuously during the full course of the campaign. Aerosols pumped through one of the ([MAST-PUMP]) inlets were channeled through a conductive tubing of 1.9 cm inner diameter to four parallel 47mm filter holders installed in the rear hold using a vacuum pump (Diaphragm pumpME16 NT, VACUUBRAND BmbH & Co KG, Wertheim, Germany) at a minimum flow rate of 30 lpm (20lpm prior to may 2016). Air was conducted to an optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) measuring and counting particles in the size range 0.25 - 32 µm as a 30 minutes average, both the particle concentration (nb cm-3) together with its normalized size distribution (dN/dlogDp (nb cm-3 log(nm)-1) i.e., the concentration divided by the log of the width of the bin).
    Keywords: aerosol; DATE/TIME; Fondation Tara Expeditions; FondTara; LATITUDE; Log-normal particle size distribution; LONGITUDE; Optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) measuring and counting particles in 30 minutes average; Pacific Ocean; Particle concentration, standard deviation; Particle number, total; size distribution; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; UMS; Underway, multiple sensors
    Type: Dataset
    Format: text/tab-separated-values, 1851846 data points
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  • 7
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from an optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) instrument acquiring continuously during the full course of the campaign. Aerosols pumped through one of the ([MAST-PUMP]) inlets were channeled through a conductive tubing of 1.9 cm inner diameter to four parallel 47mm filter holders installed in the rear hold using a vacuum pump (Diaphragm pumpME16 NT, VACUUBRAND BmbH & Co KG, Wertheim, Germany) at a minimum flow rate of 30 lpm (20lpm prior to may 2016). Air was conducted to an optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) measuring and counting particles in the size range 0.25 - 32 µm every 60 seconds.
    Keywords: aerosol; DATE/TIME; Fondation Tara Expeditions; FondTara; LATITUDE; LONGITUDE; Optical particle counter ([EDM]; EDM180 GRIMM Aerosol Technik Ainring GmbH & Co. KG, Ainring, Germany) measuring and counting particles in the size range 0.25 - 32 µm every 60 seconds; Pacific Ocean; Particle concentration, standard deviation; Particle number, total; size distribution; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; UMS; Underway, multiple sensors
    Type: Dataset
    Format: text/tab-separated-values, 30312 data points
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  • 8
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from Equilibrator Inlet Mass Spectrometer [EIMS] (Pfeiffer Vacuum Quadrupole 1–100 amu) instruments acquiring continuously during the full course of the campaign. Surface seawater was pumped continuously through a hull inlet located 1.5 m under the waterline using a membrane pump (10 LPM; Shurflo), circulated through a vortex debubbler, a flow meter, and distributed to a number of flow-through instruments.
    Keywords: argon; DATE/TIME; Equilibrator Inlet Mass Spectrometry (EIMS); Fondation Tara Expeditions; FondTara; LATITUDE; LONGITUDE; Oxygen; Oxygen/Argon ratio; Pacific Ocean; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; UMS; Underway, multiple sensors
    Type: Dataset
    Format: text/tab-separated-values, 146536 data points
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  • 9
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from CDOM fluorometer [WSCD] (WETLabs) instruments acquiring continuously during the full course of the campaign. Surface seawater was pumped continuously through a hull inlet located 1.5 m under the waterline using a membrane pump (10 LPM; Shurflo), circulated through a vortex debubbler, a flow meter, and distributed to a number of flow-through instruments. The CDOM fluorometer [WSCD] (WETLabs), was added to the underway system to measure the fluorescence of colored dissolved organic matter [fdom].
    Keywords: CTD, Sea-Bird; measured with Thermosalinograph (TSG) sensor; DATE/TIME; DOM; Fluorescence, dissolved organic matter; Fluorescence, dissolved organic matter, standard deviation; Fondation Tara Expeditions; FondTara; LATITUDE; LONGITUDE; Number; Pacific Ocean; Salinity; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; Temperature, water; UMS; Underway, multiple sensors; WET Labs CDOM
    Type: Dataset
    Format: text/tab-separated-values, 2740189 data points
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  • 10
    Publication Date: 2024-01-06
    Description: The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean, and sampled the surface of oceanic waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study corals, fish, plankton, and seawater, and included the collection of samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide the continuous dataset originating from PAR sensor (Biospherical Instruments Inc. QCR-2150) acquiring continuously during the full course of the campaign and mounted at the stern of the boat (~7 m altitude).
    Keywords: CTD, Sea-Bird; measured with Thermosalinograph (TSG) sensor; DATE/TIME; Fondation Tara Expeditions; FondTara; LATITUDE; LONGITUDE; Number; Pacific Ocean; PAR; PAR sensor, Biospherical, QCR-2150; Radiation, photosynthetically active; Radiation, photosynthetically active, standard deviation; Salinity; SV Tara; TARA_2016-2018; Tara_Pacific; TARA_PACIFIC_2016-2018; Tara Pacific Expedition; Temperature, water; UMS; Underway, multiple sensors
    Type: Dataset
    Format: text/tab-separated-values, 4154275 data points
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