Preliminary global database of known and inferred gas hydrate locations

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Waite, William F., Ruppel, Carolyn D., Boze, Lee-Gray, Lorenson, Thomas D., Buczkowski, Brian J., McMullen, Katherine Y., and Kvenvolden, Keith A., 20200611, Preliminary global database of known and inferred gas hydrate locations: data release DOI:10.5066/P9LLFVJM, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P9LLFVJM
   • https://www.sciencebase.gov/catalog/item/5eb413a282ce25b5135a9f2a

   Other_Citation_Details:

   Suggested citation: Waite, W.F., Ruppel, C.D., Boze, L-G., Lorenson, T.D., Buczkowski, B.J., McMullen, K.Y., and Kvenvolden, K.A., 2020, Preliminary global database of known and inferred gas hydrate locations: U.S. Geological Survey data release, https://doi.org/10.5066/P9llFVJM.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -178.4
   East_Bounding_Coordinate: 178
   North_Bounding_Coordinate: 80
   South_Bounding_Coordinate: -75.9
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5eb413a282ce25b5135a9f2a?name=USGSHydrateDatabaseMap2020.jpg (JPEG)

   Map showing the known and inferred gas hydrate locations

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 1990

   Ending_Date: 2020

   Currentness_Reference:

   The data range represents the years over which this database was compiled and maintained by the USGS Gas Hydrates Project.

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: XLXS spreadsheet
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (438)
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 1. Longitudes are given to the nearest 1. Latitude and longitude values are specified in Decimal degrees.
7. How does the data set describe geographic features?

   USGSglobalhydratedatabase2020.xlsx

   Excel Office 365 worksheet (Source: Producer Defined)

   Location

   Text field providing up to three location designations separated by dashes, starting with the most general and progressing to the most specific. For marine locations, the first designator refers to the appropriate ocean or basin. For onshore locations (permafrost or Lake Baikal), the first designator refers to the country. For locations in the northern Gulf of Mexico, the number following the third designator for some entries is the Outer Continental Shelf lease block as designated by the U.S. Bureau of Ocean Energy Management. Geographic designators are sometimes more specific for inferred locations than known locations since the inferred locations often refer to bottom simulating reflectors that are recognized in a specific small region. Some locations have a designator that includes a slash ("/"). This is the case for the Sea of Japan/East Sea or East Sea/Sea of Japan since this same body of water is referred to using both names, usually dependent on the nationality of the lead author of the associated reference. The Tibetan/Qinghai Plateau is also referred to with both names to assist users in understanding the location. (Source: Producer Defined) ASCII text

   Latitude

   Decimal degree with positive denoting north latitude and negative denoting south latitude. Locations reported in the original publications varied in precision from a degree to thousandths of a degree. Many of the original publications reported locations in degree-minute-second or degree-decimal minutes format. All locations were converted to decimal degrees. (Source: Producer Defined)

   Range of values
   Minimum:	-75.9
   Maximum:	80.0
   Units:	degree

   Longitude

   Decimal degree with positive values denoting east longitude relative to the prime meridian and negative denoting west longitude. Locations reported in the original publications varied in precision from a degree to thousandths of a degree. Many of the original publications reported locations in degree-minute-second or degree-decimal minutes format. All locations were converted to decimal degrees. (Source: Producer Defined)

   Range of values
   Minimum:	-178.0
   Maximum:	178.4
   Units:	degree

   Status

   Text designator distinguishing between known and inferred occurrences of gas hydrates (Source: Producer Defined)

   Value	Definition
   known	locations where gas hydrate has been confirmed
   inferred	location where gas hydrate indicators are recognized, but no visual confirmation has been made

   Reference

   Text field that contains the citation to the scientific work or works that describe the gas hydrate finding, including the digital object identifier (DOI) or URL when available. (Source: Producer Defined) ASCII text

   Notes

   This is a text field used to address any inconsistencies in the original locations (e.g., swapped latitude and longitude coordinates), source of coordinates if not provided in the publication (e.g., interpolated from map)......The field is blank if no additional information is necessary. (Source: Producer Defined) ASCII text

   Evidence

   For known hydrates, the text field indicates "Directly observed." For inferred gas hydrates, the text field contains a description of the type of indicator. A single record can have more than one of these values separated by a comma. (Source: Producer Defined)

   Value	Definition
   BSR	bottom simulating reflections defined based on single or multichannel seismic data
   carbonate indicators	presence of authigenic carbonate and carbonate formations inferred by reference authors to indicate hydrate
   chlorinity	refers to chloride anomalies associated with freshening of pore waters, which occurs when gas hydrate dissociates in sediments and dilutes the pore waters
   compliance	indicates that the analysis of seismic compliance contributed to the inference of subseafloor gas hydrates
   deepwater seepage	describes a seafloor methane seep within the pressure and temperature conditions for gas hydrate stability, meaning that gas hydrate is inferred to be present beneath the sea floor near the seep
   Directly observed	for known gas hydrates, the hydrate has been observed at the seafloor or recovered in cores
   electromagnetic	refer to controlled source electromagnetic (EM) surveys or similar areal surveys using other EM technologies
   gas concentrations	refer to characteristics of recovered sediments, which may include large amounts of gas upon recovery or may generate large volumes of gas as gas hydrate dissociation evolves
   gas escape features	indicate indirect seafloor evidence (pockmarks) for gas escape in areas where gas hydrate should be stable
   gravity	refers to the use of gravity anomalies to constrain gas hydrate locations
   IR anomalies	indicates thermal infrared imaging of recovered cores to highlight cold spots associated with the presence or dissociation of gas hydrate in sediments
   resistivity	Elevated resistivity values are the most commonly used well log indicator to infer gas hydrates in this database, and "resistivity" is used when this was the key measurement that contributed to the inference of gas hydrate
   seafloor morphology	indicates the low hummocks sometimes associated with hydrate-cored seafloor mounds
   sediment texture	denotes observations of the characteristic moussey texture of recovered sediment cores following gas hydrate dissociation
   sediment structures	denotes sedimentary structures interpreted in the reference as being typical of gas hydrate provinces
   seismic	seismic analyses other than bottom simulating reflections (BSRs); analyses may include seismic attributes, amplitude versus offset, analysis of frequency characteristics indicating gassy sediments, velocity analyses, or P-wave measurements on recovered cores
   other	not fitting into any of the other defined categories
   well logs	inference based on the analysis of conventional wireline logging records or those obtained via logging while drilling

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • William F. Waite
   • Carolyn D. Ruppel
   • Lee-Gray Boze
   • Thomas D. Lorenson
   • Brian J. Buczkowski
   • Katherine Y. McMullen
   • Keith A. Kvenvolden
2. Who also contributed to the data set?
   The database has been compiled and maintained since approximately 1990 by scientists in the USGS Gas Hydrates Project. The database was initiated at the predecessor to the Pacific Coastal and Marine Science Center in the earliest 1990s. The database has been maintained by numerous personnel at the Woods Hole Coastal and Marine Science Center since ~2010.
3. To whom should users address questions about the data?
   William F. Waite

   U.S. Geological Survey, Woods Hole Coastal and Marine Science Center

   Research Geophysicist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   (508) 548-8700 x2346 (voice)

   (508) 457-2310 (FAX)

   wwaite@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?
2. How were the data generated, processed, and modified?

   Date: 2020 (process 1 of 3)

   Publications that describe direct observations of gas hydrate (e.g., at the sea floor) or the recovery of gas hydrate by coring, drilling, or other means were reviewed and the locations of the gas hydrate assembled in a database. These gas hydrates are considered "known" because their existence has been visually confirmed. Publications that describe indirect evidence for gas hydrates were similarly reviewed and information about these locations assembled in the database. Indirect evidence for gas hydrates may include well logs (especially resistivity logs), thermal infrared anomalies in recovered cores, identification of bottom simulating reflections (BSRs), freshening of pore waters owing to hydrate dissociation, sediment texture (moussey sediments resulting from hydrate dissociation), advanced seismic analyses, or other indicators. In cases for which actual geographic coordinates were not provided by the authors of publications, locations were extracted from maps within the publications. Some gas hydrate locations may be missing from the database if neither the geographic information or a labelled map were not provided in the publications although best efforts were made to estimate the locations when possible. Since approximately 2015, the focus for the database compilation has been on finding newly published locations for gas hydrate with online notification services used to track new publications in the discipline. In ~2013, existing entries were carefully checked to verify the citation, hydrate location, and other information describing the gas hydrate occurrences. This compilation is ongoing and represents work completed from ~1990 to the present (2020). Note that a location may have both known hydrates and inferred hydrates. The locations with "inferred" hydrates do not become "known" once hydrate has been recovered there. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: William F. Waite

   Research Geophysicist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   USA

   508-548-8700 x2346 (voice)

   508-457-2310 (FAX)

   wwaite@usgs.gov

   Date: 15-May-2020 (process 2 of 3)

   Location errors, inconsistent geographic descriptors, and faulty citations were addressed. Hydrate inferences were assigned consistent descriptors. Where available, the digital object identifiers were added to the references, which are provided in the citation format given by the original publication. The Excel Office 365 XLSX file was written in native format. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Carolyn Ruppel

   Research Geophysicist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   USA

   508-548-8700 x2263 (voice)

   508-457-2310 (FAX)

   cruppel@usgs.gov

   Date: 07-Aug-2020 (process 3 of 3)

   Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

3. What similar or related data should the user be aware of?
   Ruppel, Carolyn D., and Waite, William F., 2020, Grand Challenge: Timescales and Processes of Methane Hydrate Formation and Breakdown, with Application to Geologic Systems: Journal of Geophysical Research DOI:10.1029/2018JB016459, American Geophysical Union, Washington, D.C..

   Online Links:

   • https://doi.org/10.1029/2018JB016459

   Other_Citation_Details:

   Ruppel, C.D. and Waite, W.F., 2020, Grand Challenge: Timescales and Processes of Methane Hydrate Formation and Breakdown, with Application to Geologic Systems, J. Geophysical Research, 125, e2018JB016459.

   Ruppel, Carolyn D., 2018, Gas hydrate in nature: US Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/fs20173080

   Kvenvolden, Keith A., 20100614, Gas hydrates-geological perspective and global change: Reviews of Geophysics 31(2), American Geophysical Union (AGU), Washington, D.C..

   Online Links:

   • https://doi.org/10.1029/93RG00268

   Other_Citation_Details: pages 173-187
   

   Beaudoin, Y.C., Waite, W., Boswell, R., and Dallimore, S.R., 2014, Frozen Heat: A UNEP Global Outlook on Methane Gas Hydrates. Volume 1: United Nations Environment Programme, Norway.

   Online Links:

   • https://wedocs.unep.org/bitstream/handle/20.500.11822/9355/GasHydrates_Vol1_screen.pdf

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?
   The only numeric values in this dataset are the latitude and longitude for known and inferred gas hydrates as reported in published works. For known gas hydrate locations and inferred gas hydrate occurrences not associated with bottom simulating reflections (BSRs), the values recorded here are only as accurate as those in the original published works. When the published work was describing a particular geographic area, but the coordinates did not plot in that area, the compilers of this dataset investigated the error in the reported locations. Usually, the error was related to the authors of the published work having accidentally switched latitude and longitude or given an unsigned latitude or longitude. If such corrections were made, they are described in the "notes" field. Inferred gas hydrate locations associated with BSRs are denoted with geographic coordinates chosen from within the region where the BSRs are described in the published works. These single points cannot represent the entire areal extent of the BSRs.
2. How accurate are the geographic locations?
   The locations are extracted directly from published reports and have the accuracy provided in the original reports. The locations were recorded using various datums that are not documented in most of the reports or in this database. No corrections for datums were made by the compilers of this dataset. In some cases, it was clear to the compilers of this database that the latitude and longitude in the original reports had been switched, and this error is described in the "notes" column and the corrected latitude and longitude reported.
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   Complete to the best knowledge of the compilers. For gas hydrate locations reported more than once in the literature, the first publication or the first few publications that completely characterize the gas hydrate recoveries or inferences are cited. Subsequent studies visiting the same location are not cited here. Note that a BSR was described on Alpha Ridge in the Central Arctic Ocean by Jackson, H.R., Forsyth, D.A., and Johnson, G.L., 1986, Oceanic Affinities of the Alpha Ridge, Arctic Ocean, Marine Geology, v. 73, p. 237-261. This inference is not included in this database because one of the compilers noted in 2018 that the feature described in that reference was unlikely to be a BSR and corresponded with H. Ruth Jackson, who confirmed that the feature was not a BSR.
5. How consistent are the relationships among the observations, including topology?
   The geographic coordinates are plausible. For this data set, geographic coordinates are reported only one time even if gas hydrate was recovered at many depths within the same well. If known and inferred gas hydrate coordinates were exactly the same, as is sometimes the case when gas hydrate is recovered at one depth in a well and inferred at another, the entry for the known gas hydrate was retained and assumed to supersede inferences of gas hydrate at other depths in the well. Geographic coordinates reported for different hydrate locations sometimes vary only in the 4th decimal place in the database. In these cases, the original geographic coordinates refer to closely-spaced wells drilled during expeditions investigating gas hydrates. The geographic coordinates reported in the database were plotted on a world map to ensure that the locations were logical for the known conditions that govern the existence of gas hydrate (e.g., not in the middle of a continent in an area lacking permafrost; not on a mid-ocean ridge) and to check that the locations corresponded to the regions described in the published works.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? The dataset contains the data in Excel XLSX format only (USGSglobalhydratedatabase2020.xlsx), a browse graphic of data locations (USGSHydrateDatabaseMap2020.jpg), and the associated FGDC CSDGM metadata.
3. What legal disclaimers am I supposed to read?
   Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	The dataset contains the XLSX format of the data, a browse graphic, and associated FGDC CSDGM metadata. in format XLXS (version Microsoft Excel Office 365) Size: 1
     Network links:	https://www.sciencebase.gov/catalog/file/get/5eb413a282ce25b5135a9f2a https://www.sciencebase.gov/catalog/item/5eb413a282ce25b5135a9f2a

   • Cost to order the data: None

5. What hardware or software do I need in order to use the data set?
   To utilize these data, the user must have software capable of reading Excel files and displaying a JPEG file.

Who wrote the metadata?

Dates:

Last modified: 19-Mar-2024

Metadata author:

Carolyn D. Ruppel

U.S. Geological Survey, Northeast Region

Research Geophysicist

384 Woods Hole Road

Woods Hole, MA

United States

508-548-8700 x2339 (voice)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319)

Metadata standard:

FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)