Seismic Reflection Results from the Gyre 1997 Cruise at the Bryant Canyon of the Louisiana Gulf Coast

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Nealon, Jeffrey

Publication_Date: 1999

Title:

Seismic Reflection Results from the Gyre 1997 Cruise at the Bryant Canyon of the Louisiana Gulf Coast

Publication_Information:

Publication_Place: Woods Hole, MA

Publisher: U.S. Geological Survey

Other_Citation_Details: none

Online_Linkage: none

Description:

Abstract:

This CD-ROM contains digital high resolution seismic-

reflection data collected during the USGS GYRE 97006

cruise. The coverage is the offshore Louisana continental slope, Gulf of Mexico. The seismic-reflection data are stored as IBM 4 bit interger SEG-Y format that can be read and

manipulated by most seismic-processing software. Much of the information specific to the data are contained in the headers of the SEG-Y format files. The file system format is ISO 9660 which can be read with DOS, Unix, and MAC operating systems with the appropriate CD-ROM driver

software installed. This directory contains the processed (using Promax 7.2) and unprossesd (RAW) GI air gun data collected on the GYRE 97006 cruise. These data were collected using a Seismic Systems Inc. generated

injected (GI) air gun source. On this cruise the GI gun was configured with two 105 cu. in. chambers, a total of 210 cu. in. The GI gun works by using one chamber for a primary pulse and the second chamber injects a pulse near the maximum expansion of the primary pulse. This results in a dampening effect on the collapse of the primary bubble pulse. The data were logged on an Intel based PC computer (Mudseis system). The data are

two-channel (two traces per shot).

Purpose:

The seismic-reflection data are being archived so that

further digital processing can be done for the seafloor

mapping project: TECTONICS AND SEDIMENTARY PROCESSES OF THE SALT DEFORMED TEXAS-LOUISIANA CONTINENTAL SLOPE. This project proposes (1) mapping the surficial geology of a large part of the TX-LA slope using advanced

processing techniques and existing GLORIA and multibeam data, (2) conducting a higher resolution sidescan and

sampling cruise to refine the understanding of tectonic,

sediment supply, and oceanographic controls on

sedimentary processes, (3) linking the surficial geology with the subsurface structures and stratigraphy for modern and ancient comparison of sedimentary systems, and (4) integrating data into a three-dimensional model of depositional systems in this complex environment.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19970409

Beginning_Time: 045227

Ending_Date: 19970413

Ending_Time: 131459

Currentness_Reference:

Status:

Progress: In work

Maintenance_and_Update_Frequency: Unknown

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -92.833333

East_Bounding_Coordinate: -91.916667

North_Bounding_Coordinate: 27.5

South_Bounding_Coordinate: 26.25

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: seismic reflection

Theme_Keyword: Seismic Systems Inc.

Theme_Keyword: GI Air Gun

Theme_Keyword: SEG-Y

Theme_Keyword: ISO 9660 CD-ROM

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Gulf of Mexico

Place_Keyword: Louisiana

Place_Keyword: LA

Place_Keyword: continental slope

Place_Keyword: R/V GYRE

Access_Constraints:

for U.S. Geological Survey use only

Use_Constraints:

for U.S. Geological Survey use only

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Twichell, Dave

Contact_Organization: U.S. Geological Survey

Contact_Position: Seafloor Mapping Project

Contact_Address:

Address_Type: mailing address

Address:

U.S. Geological Survey

Woods Hole Field Center

384 Woods Hole Road

Quissett Campus

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address: dtwichell@usgs.gov

Data_Set_Credit:

D. Twichell, D. Nichols, T. O'Brien, B. Irwin, V. Cross, M. Taylor D. Foster, B. Danforth, S. Harrison, J. Brand, C. Spagnuolo

Native_Data_Set_Environment: ISO 9660

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value:

Attribute_Accuracy_Explanation:

Logical_Consistency_Report:

Completeness_Report:

archive of SEG-Y format seismic data

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The ship was navigated with differential GPS

The GI air gun was towed 10 m aft of the ship

The two-channel streamer was towed 100 m aft of the

ship. Each channel consisted of a 25 m length

of streamer.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: 5-10 meters

Horizontal_Positional_Accuracy_Explanation:

the ship position is accurate within 5-10 meters

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The air gun was towed at depth of 1 meter. The

streamer was towed at a depth of 5 meters. Vertical

resolution of the seismic data is about 1-2 meters.

There was no correction to a datum such as mean sea

level.

Quantitative_Vertical_Positional_Accuracy_Assessment:

Vertical_Positional_Accuracy_Value: 1-2 meters

Vertical_Positional_Accuracy_Explanation:

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Twichell, David C.

Publication_Date: 1997

Title:

Geospatial_Data_Presentation_Form:

Source_Scale_Denomonator:

Type_of_Source_Media:

Seg-Y files on CDROM

Source_time_preiod_of_Content:

Time_preiod_of_Iinformation:

Single_Date/Time

Calendar_date 1997

Souce_Currentness_Reference:

Source_Citation:

Process_Step:

Process_Description:

Flow 1 : load file and geometry

2D Marine geometry spreadsheet

Seg-Y Input

File to input: Raw.seg-y

Store Processing History:Yes

Input Auxiliary Traces: Yes

Get Channel Number from Trace Headers: Yes

Input Trace Format: Get from Headers

Display ensemble Formation: No

Data Input Sample Rate: 0.5 msec

Maximum Time to input: variable

Is this Stacked Data: No

Max Traces Per Ensemble: 120

Primary Sort Header Word: SHOT

Input Primary Selection Choice:Input all

Input secondary selection Choice:None

Input global XY coordinates: No

Use coordinate Scalar: Yes

Remap Seg-Y header Values: No

Inline Geometry header Load

water velocity: 1525

Primary header to match database: FFID

Secondary Header to match database: None

Match by Valid trace Number: NO

Drop traces with Null CDP headers: No

Drop Traces with Null receiver Headers: No

Verbose Diagnostics: YES

Trace header Math

select Mode:fixed equation Mode

define header equation:FFID =CDP

Disk Data Output

output dataset file Name: geom

New or existing file:New

record length to output:0(default parameter means include all)

Trace sample format:16 bit

Skip primary disk storage:No

Flow 2: Mute and Deconvolution

Disk Data Input

Read data from other lines/surveys:No

Select input file: geom

Trace read option: Get all

Read data multiple times: No

Input trace headers only: No

Override input datas sample interval:No

Trace Muting

Reapply Previous mutes: no

Mute time reference:Time 0

Type of Mute: TOP

Starting ramp:30

Extrapolate mute times:No

Get Mute Times from Database:Yes

Select Database:Topmute(Horizon picked ~300 ms above seafloor)

True Amplitude recovery

Apply spherical divergence corrections: NO

Apply inelastic attenuation correction: NO

Apply db/sec corrections:YES

DB per second constant:6

Apply time raise to a power corrections:NO

Time power constant:NO

Apply effect to data or remove function:APPLY

Maximum application Time: 3500-4000

Spiking Predictive decon

Type of deconvolution:MIN PHASE SPIKING

Decon Operator length:80

Operator white noise level:.1

window rejection length:2

Time gate reference:DATABASE FILE

Select decon gate from Database: Yes Select database:DECON

Output traces or filters:TRACES

Apply a band pass filter after decon:NO

Reapply mutes after decon:YES

Disk Data Output

Output dataset file Name:decon

New or existing file:New

record length to output:0(default parameter means include all)

Trace sample format:16 bit

Skip primary disk storage:No

Flow 3 Stack

Disk Data Input

Read data from other lines/surveys: No

Select input file:decon

Trace read option:sort

Primary Sort header word:CDP

Secondary sort header word:NONE

Sort order dataset:*/

Presort in memory or disk:Memory

Read data multiple times:No

Input trace headers only: No

Override input datas sample interval:No

CDP Ensemble Stack

sort order of input ensembles:CDP

Method of trace summing:Mean

root Power scalar for stack normalization:0.5

Apply final datum statics after Stack:Yes

Has NMO been applied:No

Disk Data Output

Output dataset file Name:stack

New or existing file:New

record length to output:0(default parameter means include all)

Trace sample format:16 bit

Skip primary disk storage:No

Disk Data Input

Read data from other lines/surveys:No

Select input file:stack

Trace read option:get all

Read data multiple times:No

Input trace headers only:No

Override input data's sample interval:No

Bandpass Filter

Type of Filter:single filter

Type of filter specification:ormsby bandpass

Phase of filter:Zero

domain of filter application:Frequency

Percent zero padding for FFT:25

Apply notch filter:no

Ormbsby bandpass filter values:4-8-100-150

Reapply trace mute after filter:yes

Seg-Y Output

type of seg-y:standard

file name:line1pro.sgy

Retrieve history form header:yes

copy reel header:default

job id for binary header:9999

line number for binary header:9999

desired trace format:4 bit integer

maximum time to output:variable

remap seg-y header values:no

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference:

Gulf of Mexico, Louisiana Continental Slope

Direct_Spatial_Reference_Method: raster

Raster_Object_Information:

Raster_Object_Type: Voxel

Row_Count: > 10000

Column_Count: 1

Vertical_Count: 4096

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name:

Universal_Transverse_Mercator:

UTM_Zone_Number: 15

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: .9997

Longitude_of_Central_Meridian: -93

Latitude_of_Projection_Origin: 0

False_Easting: 0

False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 5

Ordinate_Resolution: 5

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298257

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: assumed sea level

Altitude_Resolution: 1

Altitude_Distance_Units: two-way travel time

Altitude_Encoding_Method: Attribute values

Depth_System_Definition:

Depth_Datum_Name: fish depth below sea level (local surface)

Depth_Resolution: 1

Depth_Distance_Units: meters

Depth_Encoding_Method: Attribute values

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

Entity_and_Attribute_Detail_Citation:

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Soderberg, Nancy

Contact_Organization: U.S. Geological Survey

Contact_Position: Data Library

Contact_Address:

Address_Type: mailing address

Address:

U.S. Geological Survey

Woods Hole Field Center

384 Woods Hole Road

Quissett Campus

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address: nsoderberg@usgs.gov

Resource_Description:

U.S. Geological Suvey Internal CD-ROM Data Archive

Distribution_Liability:

This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: ISO 9660 CD-ROM

Format_Version_Number: ISO 9660

Format_Specification:

Format_Information_Content: SEG-Y

File_Decompression_Technique: none

Transfer_Size: 650 MB

Digital_Transfer_Option:

Offline_Option:

Offline_Media: CD-ROM

Recording_Capacity:

Recording_Density: 512

Recording_Density_Units: bytes

Recording_Format: ISO 9660

Compatibility_Information: UNIX, DOS, MAC

Fees:

Metadata_Reference_Information:

Metadata_Date: 19970408

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Foster, David

Contact_Organization: U.S. Geological Survey

Contact_Position: Geophysics Group

Contact_Address:

Address_Type: mailing address

Address:

U.S. Geological Survey

Woods Hole Field Center

384 Woods Hole Road

Quissett Campus

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address: dfoster@usgs.gov

Metadata_Standard_Name:

FGDC Content Standard

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: universal time

Metadata_Access_Constraints: none

Metadata_Use_Constraints: none