Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2014 Title: NC_seisimages: PNG format images of EdgeTech SB-512i chirp seismic-reflection data collected in May 2012 by the U.S. Geological Survey within the Norfolk Canyon, mid-Atlantic margin Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 2014-1118 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2014/1118/data/Norfolk_Canyon/images/NorfolkCanyon_seisimages.zip Larger_Work_Citation: Citation_Information: Originator: Jeffrey Obelcz Originator: Daniel S. Brothers Originator: Uri S. ten Brink Originator: Jason D. Chaytor Originator: Charles R. Worley Originator: Eric M. Moore Publication_Date: 2014 Title: Chirp Seismic-Reflection Data From the Baltimore, Washington, and Norfolk Canyons, U.S. Mid-Atlantic Margin Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 2014-1118 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: http://dx.doi.org/10.3133/ofr20141118 Online_Linkage: http://pubs.usgs.gov/of/2014/1118/ Description: Abstract: A large number of high-resolution geophysical surveys between Cape Hatteras and Georges Bank have been conducted by federal, state, and academic institutions since the turn of the century. A major goal of these surveys is providing a continuous view of bathymetry and shallow stratigraphy at the shelf edge in order to assess levels of geological activity during the current sea level highstand. In 2012, chirp seismic-reflection data was collected by the U.S. Geologial Survey aboard the motor vessel Tiki XIV near three United States mid-Atlantic margin submarine canyons. These data can be used to further our understanding of passive continental margin processes during the Holocene, as well as providing valuable information regarding potential submarine geohazards. For more information on the U.S. Geological Survey involvement in this effort, see . Purpose: PNG images of each seismic profile were generated in order to enable incorporation of images of the seismic profiles into Geographic Information System (GIS) projects and data archives. The PNG images represent over 330 km of EdgeTech SB-512i chirp seismic-reflection profiles collected within and around Norfolk Canyon. These images are provided as a convenient and rapid method for viewing the seismic-reflection data. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20120525 Beginning_Time: 0937 (UTC) Ending_Date: 20120527 Ending_Time: 0715 (UTC) Currentness_Reference: ground condition of survey on dates 20120525-20120527 Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -74.818539 East_Bounding_Coordinate: -74.530725 North_Bounding_Coordinate: 37.193447 South_Bounding_Coordinate: 37.003275 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Seafloor Theme_Keyword: Marine Geology Theme_Keyword: PNG Theme_Keyword: seismic reflection Theme_Keyword: SEGY Theme_Keyword: seismic profile Theme_Keyword: subbottom Theme_Keyword: EdgeTech Theme_Keyword: 512i Theme_Keyword: image Theme_Keyword: chirp Theme_Keyword: M/V Tiki XIV Theme_Keyword: M/V Tiki 14 Theme_Keyword: field activity 2012-005-FA Theme_Keyword: field activity number 12005 Theme_Keyword: USGS CMG InfoBank ID T-05-12-MC Theme_Keyword: submarine canyon Theme_Keyword: geohazards Theme_Keyword: continental margin Theme_Keyword: seismic-reflection profile Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Place: Place_Keyword_Thesaurus: General Place_Keyword: North America Place_Keyword: United States Place_Keyword: Atlantic Ocean Place_Keyword: mid-Atlantic margin Place_Keyword: Maryland Place_Keyword: Norfolk Canyon Place_Keyword: Baltimore Canyon Trough Stratum: Stratum_Keyword_Thesaurus: General Stratum_Keyword: Seafloor Stratum_Keyword: Subsurface Stratum_Keyword: sea floor Temporal: Temporal_Keyword_Thesaurus: General Temporal_Keyword: 2012 Access_Constraints: None. Use_Constraints: Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the source of this information. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2014/1118/data/Norfolk_Canyon/images/seisimage.jpg Browse_Graphic_File_Description: Thumbnail of a sample seismic-reflection profile. Browse_Graphic_File_Type: JPEG Native_Data_Set_Environment: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.1850 Cross_Reference: Citation_Information: Originator: John Stockwell Publication_Date: 2011 Title: Seismic Uni*x Publication_Information: Publication_Place: Golden, CO Publisher: Center for Wave Phenomena - Colorado School of Mines Online_Linkage: Cross_Reference: Citation_Information: Originator: Paul Henkart Publication_Date: 2011 Title: SIOSEIS Publication_Information: Publication_Place: La Jolla, CA Publisher: Scripps Institution of Oceanography, UC San Diego Online_Linkage: Cross_Reference: Citation_Information: Originator: Michael W. Norris and Alan K. Faichney Publication_Date: 2002 Title: SEGY Rev. 1 Data Exchange Format 1 Publication_Information: Publication_Place: Tulsa, OK Publisher: Society of Exploration Geophysicists Online_Linkage: Data_Quality_Information: Logical_Consistency_Report: Processed seismic data were converted to PNG format for ease of seismic trace display. Quality control was conducted during processing. Completeness_Report: Lines were serially recorded during the survey in the format "LXF1". When a file is named "LXF2" or has a file number greater than 2, the recording parameters were usually changed (record length and shot rate), as recorded in the ship's log. The following lines were either not recorded or excluded from this data release: L82F1, L87F1, L99F1, L115F1, L142F1 (all excluded due to negligible length). Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: Unpublished Material Title: raw seismic data Type_of_Source_Media: disc Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20120524 Beginning_Time: 1819 (UTC) Ending_Date: 20120527 Ending_Time: 2355 (UTC) Source_Currentness_Reference: ground condition Source_Contribution: Seismic-reflection data acquisition: Chirp seismic data were collected using an EdgeTech SB-0512i towfish (0.5-4.5 kHz pulse, 50 ms pulse length), which was towed astern of the M/V Tiki XIV of Ocean City, MD. Chesapeake Technologies' SonarWiz (v.4.04.0031) seismic acquisition software was used to control the chirp, digitally log trace data in the SEG-Y Rev. 1 format (IEEE floating point), and record GPS navigation coordinates to the SEG-Y trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). Trace lengths are constant within lines, but vary from line to line due to variable water depth in the survey area (the minimum trace length was 250 ms and the maximum 1400 ms). This yields a range of samples per trace from approximately 5435 (250 ms trace length) to 30435 (1400 ms trace length). Sample interval was kept at a constant .000046 s. The ping rate was set to be consistent with the trace length, so it varied between 250 ms and 1400 ms. Process_Step: Process_Description: SIOSEIS (version 2010.2.11) was used to mute the first 10 ms of each seismic trace of select lines (this process step is indicated in the line name by the _topmute suffix). SIOSEIS was then used to predict the vertical location of the sea floor for traces by identifying the first downtrace instance of an amplitude that exceeded a user-defined threshold value. This seafloor pick was then used by SIOSEIS process 'swell' to minimize the effect of sea surface heave. The output SEG-Y file is in the format , and these files were then used to create browse images and digital interpretation. Process_Date: 201206 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Process_Step: Process_Description: SEG-Y trace data of lines that SIOSEIS could not seafloor autopick (usually due to an acoustically faint seafloor-sediment interface) were imported into IHS Kingdom Suite (version 8.7.1), a digital seismic interpretation software. The seafloor was manually picked using an interactive horizon digitizer tool, and seafloor horizons for these lines were exported as trace-time (one-way travel time) pair ASCII text files. Process_Date: 201206 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Process_Step: Process_Description: SIOSEIS is used to insert the trace-time pairs exported from Kingdom Suite (detailed in process step 2) into the SEG-Y trace headers and minimize the effect of sea surface heave using process 'swell'. The output files are in the format (images that are in the format LxFx_topmute_sf described in process step 1 did not need to be manually picked in Kingdom Suite), and were the SEG-Y files used for creation of browse images and digital interpretation. Process_Date: 201206 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Process_Step: Process_Description: Seismic Unix (version 4.2) was used to read all SEG-Y files produced in process steps 1 and 3 and write a Seismic Unix file for each corresponding SEG-Y file. Seismix Unix was then used to plot the SU files as 8 bit grayscale Postscript files using the SU 'psimage' algorithm. Images were created with a variable horizontal scale and variable TWTT depending on trace length of a given line. Each image is not representative of the entire SEG-Y file; the top and bottom of each profile is cropped to only display areas of subbottom penetration. Postscript images were converted to PNG format using ImageMagick (version 6.7.0). The x-axis of the images represents ffid and the y-axis is two-way travel time in seconds. Process_Date: 201206 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: PNG Format_Specification: Portable Network Graphics Image Format_Information_Content: Zip-compressed PNG images and associated metadata for processed EdgeTech SB-512i chirp seismic-reflection profiles collected in and around Norfolk Canyon by the U.S. Geological Survey in 2012. This metadata file describes both the uncompressed (149 MB) and zip-compressed images. File_Decompression_Technique: Use WinZip, 7zip, Peazip or pkUnzip. Compressed with WinZip v. 14.0. Transfer_Size: 184.3 MB Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2014/1118/data/Norfolk_Canyon/images/NorfolkCanyon_seisimages.zip Network_Resource_Name: http://pubs.usgs.gov/of/2014/1118/ofr2014-1118-data-catalog.html Access_Instructions: Data can be downloaded via the World Wide Web (WWW) Fees: none Technical_Prerequisites: These data can be viewed with any PNG image viewing software. The zip files must be uncompressed in order to view the PNG images. Metadata_Reference_Information: Metadata_Date: 20130514 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jeffrey Obelcz Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x. 2245 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: jobelcz@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time