l981aa.m77t - MGD77 data file for Geophysical data from field activity L-9-81-AA in Aleutian Arc, Alaska from 07/19/1981 to 08/13/1981

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?
   U.S. Geological Survey, and Coastal and Marine Geology Program, 2013, l981aa.m77t - MGD77 data file for Geophysical data from field activity L-9-81-AA in Aleutian Arc, Alaska from 07/19/1981 to 08/13/1981: U.S. Geological Survey, Menlo Park, CA.

   Online Links:

   • http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l981aa/mgd77/

   This is part of the following larger work.
   Steele, Wm. Clinton, Degnan, Carolyn H., Deeter, Gary B., and Riordan, Jean A., 1980, DESCRIPTION OF MARINE GEOPHYSICAL DATA COLLECTED BY THE U.S. GEOLOGICAL SURVEY AND HOW TO OBTAIN IT: U.S. Geological Survey Open File Report 167, U.S. Geological Survey, Menlo Park, CA.

   Online Links:

   • http://pubs.usgs.gov/of/1989/0167/report.pdf

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: 173.58301
   East_Bounding_Coordinate: -165.99205
   North_Bounding_Coordinate: 54.08144
   South_Bounding_Coordinate: 50.11441
   

3. What does it look like?
4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 19-Jul-1981

   Ending_Date: 13-Aug-1981

   Currentness_Reference:

   ground condition

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

   Geospatial_Data_Presentation_Form: tab-delimited ASCII text files
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      

      Indirect_Spatial_Reference: Aleutian Arc, Alaska
      

      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point
   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 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.25722210100002.
      
7. How does the data set describe geographic features?

   l981aa.m77t

   MGD77T single-beam bathymetry, gravity, and magnetics data file for l981aa (Source: NOAA's National Geophysical Data Center, See Hittelman and others (2010) Cross_Reference section above for details about the MGD77T format and citation information.)

   SURVEY_ID

   Survey identifier supplied by the contributing organization (Source: NGDC) This identifier varies in format and is supplied by the contributing organization

   TIMEZONE

   Time-zone correction (Source: NGDC) In our datasets, no correction was applied. All values equal 0.

   DATE

   YYYYMMDD (Source: NGDC)

   Range of values
   Minimum:	19810719
   Maximum:	19810813
   Units:	Year, month, day

   TIME

   Time (Source: NGDC)

   Range of values
   Minimum:	0
   Maximum:	2359.866
   Units:	hours and decimal minutes

   LAT

   Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)

   Range of values
   Minimum:	50.11443
   Maximum:	54.08144
   Units:	decimal degrees

   LON

   Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)

   Range of values
   Minimum:	-179.99889
   Maximum:	179.99854
   Units:	decimal degrees

   POS_TYPE

   Indicates how lat/lon was obtained (Source: NGDC)

   Range of values
   Minimum:	1
   Maximum:	3
   Units:	1 = observed fix, 3 = interpolated fix, nil = unspecified

   BAT_TTIME

   Bathymetry, 2-way travel time (Source: U.S. Geological Survey)

   Range of values
   Minimum:	0.045
   Maximum:	9.645
   Units:	seconds

   CORR_DEPTH

   Bathymetry, corrected depth (Source: U.S. Geological Survey)

   Range of values
   Minimum:	33.8
   Maximum:	7325.7
   Units:	decimal meters

   BAT_CPCO

   Bathymetric Correction code - details the procedure used for determining the sound velocity correction to depth (Source: NGDC)

   Range of values
   Minimum:	63
   Maximum:	63
   Units:	01-55 Matthews' Zones with zone , 59 Matthews' Zones, no zone specified, 60 S. Kuwahara Formula, 61 Wilson Formula, 62 Del Grosso Formula, 63 Carter's Tables, 88 Other (see Add. Doc.), 97 Computed using 1500 meters/sec, 98 Unknown if Corrected, 99 Unspecified

   BAT_TYPCO

   Bathymetry type code - indicates how the bathymetric value was obtained (Source: NGDC)

   Range of values
   Minimum:	1
   Maximum:	3
   Units:	1 - Observed, 3 - Interpolated (Header Seq. 12), 9 - Unspecified

   MAG_TOT

   Magnetics total field - 1st sensor (Source: NGDC)

   Range of values
   Minimum:	45788
   Maximum:	54274
   Units:	gammas

   MAG_RES

   Magnetics residual field field (Source: NGDC)

   Range of values
   Minimum:	-2734.6
   Maximum:	5653.7
   Units:	gammas

   GRA_OBS

   Observed gravity (Source: NGDC)

   Range of values
   Minimum:	980472.1
   Maximum:	981786.4
   Units:	milligals

   EOTVOS

   EOTVOS correction - E = 7.5 V cos(phi) * sin(alpha) + 0.0042 V*V (Source: NGDC)

   Range of values
   Minimum:	-53.9
   Maximum:	54.2
   Units:	milligals

   FREEAIR

   Free-air Anomaly = G(observed) minus G(theoretical) (Source: NGDC)

   Range of values
   Minimum:	-744.5
   Maximum:	567.8
   Units:	milligals

   LINEID

   LINE/TRACK/SEGMENT ID (Source: NGDC)

   Range of values
   Minimum:	4
   Maximum:	39
   Units:	Used, for example, to cross reference with seismic data.

   POINTID

   SEISMIC SHOT-POINT NUMBER/POINT ID (Source: NGDC)

   Range of values
   Minimum:	41
   Maximum:	5414
   Units:	Used, for example, to cross reference with seismic data.

   Entity_and_Attribute_Overview:

   Bathymetry, magnetic, gravity, and navigation data for U.S. Geological Survey survey l981aa in MGD77T format.

   Entity_and_Attribute_Detail_Citation:

   Attributes are obtained from MGD77T data files created from the navigation, gravity, magnetics and bathymetry best files. MGD77T is the standard, defined data format used for geophysical data in the National Geophysical Data Center. See Cross_Reference section above for citation details.

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
   • Coastal and Marine Geology Program
2. Who also contributed to the data set?

   Dave Scholl, Tracy Vallier(Chief Scientist)

3. To whom should users address questions about the data?
   Gregory K. Miller

   U.S. Geological Survey

   Physical Scientist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   (727) 803-8747, ext. 3020 (voice)

   gmiller@usgs.gov

Why was the data set created?

These data and information are intended for science researchers,students, policy makers, and general public. These data are not to be used for navigation purposes. The data are reformatted into MGD77T standard format for inclusion into NOAA's NGDC geophysical database. From there the data will be made available to GeoMapApp ( http://www.geomapapp.org/ ) and Virtual Ocean ( http://www.virtualocean.org/ ) Earth-browsing software. Access to the data is also provided via the USGS Coastal and Marine Geoscience Data System ( http://cmgds.marine.usgs.gov/ ).

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: 22-Jan-1996 (process 1 of 7)

   Navigation Data >Converted to time format with year at start. > >06/06/86 EDM DUA0:[DATA.LEE81B]L981AA.070; >DUA0:[DATA.LEE81B]FIXLATLON.EXE; >fixed longitude values less than -180 degrees > >Input was... >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.070; >DRB0:[DRS.NAV]EOTCSSP.EXE; > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was l981aa.sinse1._ on TAM295 and on TAM339 > Person who carried out this activity:
   

   U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)

   Attn: Clint Steele

   InfoBank Group Leader

   USGS, MailStop 999, 345 Middlefield Road

   Menlo Park, CA
   

   USA

   (650) 329-5055 (voice)

   (650) 329-5190 (FAX)

   infobank@octopus.wr.usgs.gov

   Date: 31-Oct-1998 (process 2 of 7)

   Gravity Data >10/31/1998 /tiger/l/l981aa/grav/l-9-81-aa.165_070 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >04/14/86 BECKIE DUA0:[DATA.JON.L981AA]L981AA.165; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >This file was a Multics file named l981aa.red_grv. >Jon Childs believes this file to be superior to >L981AA.161, which has regional value problems. > >Input was... >Converted to time format with year at start. > >06/06/86 EDM DUA0:[DATA.LEE81B]L981AA.070; >DUA0:[DATA.LEE81B]FIXLATLON.EXE; >fixed longitude values less than -180. degrees > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.070; >DRB0:[DRS.NAV]EOTCSSP.EXE; > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was l981aa.sinse1._ on TAM295 and on TAM339 > >time, lat, long, time(sec) to nearest nav fix, data values Person who carried out this activity:
   

   U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)

   Attn: Clint Steele

   InfoBank Group Leader

   USGS, MailStop 999, 345 Middlefield Road

   Menlo Park, CA
   

   USA

   (650) 329-5055 (voice)

   (650) 329-5190 (FAX)

   infobank@octopus.wr.usgs.gov

   Date: 20-Jun-2012 (process 3 of 7)

   Magnetics Data >06/20/2012 carolyn l-9-81-aa.220_070 > >Reprocessed using subroutines from Susan Macmillan's >IGRF SYNTHESIS PROGRAM >with IGRF-11 coeffiecients integrated into the source code. >/infobank/programs/mag/magred11/magred11.for >Using geodetic coordinate system (Earth shape approximated by spheriod) >with altitude 0.0 km (for sea level). > >Input was... >10/31/1998 /tiger/l/l981aa/mag/l-9-81-aa.200_070 >/bear/programs/edit/automerge/automerge > >Converted to time format with year at start. > >11/21/85 CAROLYN DRS$DATA:[L981AA.M]L981AA.200; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was L981AA._.MAGSB1 on TAM002 >was L981AA220.DAT on VAM002 > >Converted to time format with year at start. > >06/06/86 EDM DUA0:[DATA.LEE81B]L981AA.070; >DUA0:[DATA.LEE81B]FIXLATLON.EXE; >fixed longitude values less than -180. degrees > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.070; >DRB0:[DRS.NAV]EOTCSSP.EXE; > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was l981aa.sinse1._ on TAM295 and on TAM339 > >time, lat, long, time(sec) to nearest nav fix, data values Person who carried out this activity:
   

   U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)

   Attn: Clint Steele

   InfoBank Group Leader

   USGS, MailStop 999, 345 Middlefield Road

   Menlo Park, CA
   

   USA

   (650) 329-5055 (voice)

   (650) 329-5190 (FAX)

   infobank@octopus.wr.usgs.gov

   Date: 31-Oct-1998 (process 4 of 7)

   Bathymetry Data >10/31/1998 /tiger/l/l981aa/bath/l-9-81-aa.335_070 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >09/04/85 BECKIE DUA0:[DATA.L981AA.B]L981AA.335; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >This file was hand-digetized in 2-way traveltime(secs). > >Input was... >Converted to time format with year at start. > >06/06/86 EDM DUA0:[DATA.LEE81B]L981AA.070; >DUA0:[DATA.LEE81B]FIXLATLON.EXE; >fixed longitude values less than -180. degrees > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.070; >DRB0:[DRS.NAV]EOTCSSP.EXE; > >06/24/85 CAROLYN DRS$DATA:[L981AA.N]L981AA.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was l981aa.sinse1._ on TAM295 and on TAM339 > >time, lat, long, time(sec) to nearest nav fix, data values Person who carried out this activity:
   

   U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)

   Attn: Clint Steele

   InfoBank Group Leader

   USGS, MailStop 999, 345 Middlefield Road

   Menlo Park, CA
   

   USA

   (650) 329-5055 (voice)

   (650) 329-5190 (FAX)

   infobank@octopus.wr.usgs.gov

   Date: 20-Jun-2012 (process 5 of 7)

   MGD77 file creation - The available data for each cruise leg are re-formatted and combined into the Marine Geophysical Data Exchange Format (MGD77) and into the internal NGDC SEIS-NAV format by USGS using several USGS developed FORTRAN programs.The FORTRAN programs sample the navigation to every integer minute of the cruise. When necessary, the latitudes and longitudes are linearly interpolated. If the time between the actual navigation fixes exceeds five minutes, no data are included in the MGD77 file.To build the MGD77 file, gravity, magnetics, and bathymetry are added to this sampled navigation. When necessary, gravity, magnetics, and bathymetry data are linearly interpolated if the time between the actual data samples does not exceed five minutes. If a time gap exceeds this, the data are not reported.The navigation data are merged with the seismic shot point data in a SEIS- NAV format file. For this file, navigation data are interpolated for each shot point. Both types of files are written to magnetic tape and sent to NGDC. Person who carried out this activity:
   

   U.S. Geological Survey (USGS), Coastal and Marine Geology (CMG)

   Attn: Carolyn H. Degnan

   Geophysicist

   USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive

   Santa Cruz, CA
   

   USA

   (831) 460-7452 (voice)

   (831) 427-4748 (FAX)

   infobank@octopus.wr.usgs.gov

   Date: 01-Feb-2017 (process 6 of 7)

   Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Alan O. Allwardt

   Contractor -- Information Specialist

   2885 Mission Street

   Santa Cruz, CA
   

   831-460-7551 (voice)

   831-427-4748 (FAX)

   aallwardt@usgs.gov

   Date: 19-Oct-2020 (process 7 of 7)

   Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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?
   Hittelman, Allen M., Groman, Robert C., Haworth, Richard T., Holcombe, Troy L., McHendrie, Graig, Smith, Stuart M., and Metzger, Dan R., 2010, The marine geophysical data exchange format - MGD77 / MGD77T: National Geophysical Data Center, National Oceanic and Atmospheric Administration, Boulder, CO.

   Online Links:

   • http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.pdf

   Other_Citation_Details: 25 p.
   

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

1. How well have the observations been checked?
   The validity or accuracy of bathymetry and navigation data is highly qualitative and depends on equipment and operating condition variables. Data quality is unknown, MGD77T files were formatted from InfoBank files identified as best available version.
2. How accurate are the geographic locations?
   Unspecified
3. How accurate are the heights or depths?
   Unspecified
4. Where are the gaps in the data? What is missing?
   Start and end date/times of data >Navigation Data (l-9-81-aa.070) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198107190212000 198107201108000 >198107201117000 198107201649260 >198107201654360 198107240505200 >198107240533190 198108100623120 >198108100629050 198108131805000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Gravity Data (l-9-81-aa.165_070) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198107190226000 198107191506480 >198107191515000 198107200834420 >198107200844060 198107201713240 >198107201721540 198107210201540 >198107210207060 198107220431240 >198107220437540 198107221335180 >198107221437060 198107230816360 >198107230822060 198107260508240 >198107260515060 198107261854300 >198107261904300 198107270358300 >198107270405060 198107280617420 >198107280623180 198107300818000 >198107300823420 198107302338120 >198107310226480 198107311039000 >198107311044420 198107311846420 >198107312049060 198108010036180 >198108011032240 198108011810120 >198108020548240 198108021051240 >198108021100300 198108031253120 >198108031259060 198108031357120 >198108031428000 198108031855300 >198108032204360 198108040707540 >198108040714120 198108061331420 >198108061337060 198108070714540 >198108070720000 198108080919000 >198108080925120 198108090505480 >198108090511060 198108110414420 >198108110420180 198108120846480 >198108120943000 198108131742180 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Magnetics Data (l-9-81-aa.220_070) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198107190800000 198107191512070 >198107191520030 198107200840000 >198107200849080 198107200941560 >198107201633160 198107201718360 >198107201726520 198107210207000 >198107210212080 198107220436560 >198107220442520 198107221340320 >198107221442060 198107230821560 >198107230827040 198107260514000 >198107260520040 198107261900000 >198107261909320 198107270404000 >198107270410040 198107280328100 >198107280514400 198107280623000 >198107280628160 198107280827240 >198107282256360 198107290141400 >198107291204400 198107292022040 >198107300334400 198107301240080 >198107301921440 198107302256160 >198107310232160 198107310915240 >198107312054050 198108010041040 >198108011039070 198108011814510 >198108020553270 198108021057070 >198108021105310 198108031402400 >198108031433030 198108031900320 >198108032209360 198108040713000 >198108040719120 198108042338400 >198108050854400 198108051705160 >198108060916400 198108061337000 >198108061342040 198108080924200 >198108080930140 198108082258280 >198108090114200 198108092221440 >198108100038240 198108100539160 >198108100821280 198108110419560 >198108110425160 198108112310080 >198108120135090 198108120852280 >198108120948000 198108121339000 >198108121712230 198108131045000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (l-9-81-aa.335_070) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198107190300060 198107190924360 >198107190939180 198107191007300 >198107191020300 198107201215060 >198107201247300 198107201801480 >198107201812240 198107220000000 >198107220150360 198107280300000 >198107280527180 198107280829060 >198107282303120 198107290131420 >198107290630000 198107301458180 >198107301509180 198107301518120 >198107301528180 198107301528180 >198107301538420 198107310915240 >198107311000060 198108010034540 >198108011042420 198108011833540 >198108020601000 198108042338060 >198108050904180 198108051848000 >198108060955240 198108061704180 >198108061716180 198108070022120 >198108070059540 198108070343300 >198108070357300 198108070400540 >198108070413540 198108071800000 >198108071831180 198108080333120 >198108080344060 198108081108060 >198108081205060 198108082230060 >198108082241120 198108112300060 >198108112311540 198108121338300 >198108121700120 198108131040360 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Seismic Shots Data (l-9-81-aa.421_070) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198107201802220 198107220000060 >198107220145060 198107221720110 >198107221940110 198107231354470 >198107231502070 198107241036120 >198107241130120 198107250221110 >198107250250310 198107250325520 >198107250349520 198107251319520 >198107251353120 198107260210140 >198107260216540 198107261053340 >198107261205140 198107270851500 >198107271310100 198107280253350 >198108060958150 198108062358190 >198108070055190 198108080252180 >198108080258580 198108080515390 >198108080540390 198108081137190 >198108081208190 198108081718160 >198108081724560 198108082231350 >198108100823460 198108101352280 >198108101357390 198108110016060 >198108110032270 198108110055080 >198108110100310 198108110100310 >198108110106460 198108110106460 >198108110113250 198108110113250 >198108110120020 198108110120020 >198108110127340 198108110127340 >198108110135550 198108110135550 >198108110142460 198108110147400 >198108110152500 198108110152500 >198108110158320 198108110230210 >198108110235310 198108110537260 >198108110607470 198108111406020 >198108111411390 198108111715540 >198108111721220 198108112301430 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST
5. How consistent are the relationships among the observations, including topology?
   This data set is from one field activity with unknown instrument calibrations. Processed bathymetric depths were spot checked based on latitude and longitude against the Global Multi-Resolution Topography (GMRT) grid within GeoMapApp to ensure reasonable values.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None. These data are held in the public domain.
Use_Constraints:

This information is not intended for navigational purposes. Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data. Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.

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

   345 Middlefield Road MS 999

   Menlo Park, CA
   

   USA

   (650) 329-5078 (voice)

   (650) 329-5190 (FAX)
2. What's the catalog number I need to order this data set? Downloadable Data
3. What legal disclaimers am I supposed to read?

   Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	tab-delimited ASCII text files. in format MGD77t (version 10) MGD77 Size: 3.8
     Network links:	http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l981aa/mgd77/

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 19-Oct-2020

Metadata author:

Gregory K. Miller

U.S. Geological Survey

Physical Scientist

U.S. Geological Survey, 600 Fourth Street South

St. Petersburg, FL

USA

(727) 803-8747, ext. 3020 (voice)

gmiller@usgs.gov

Metadata standard:

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