USGS - science for a changing world

Data Series 1047


Digitized Analog Boomer Seismic-Reflection Data Collected During U.S. Geological Survey Cruises Erda 90-1_HC, Erda 90-1_PBP, and Erda 91-3 in Mississippi Sound, June 1990 and September 1991

Skip Links

Citation Page
Abstract
Introduction
Survey Overview
Data Acquisition
Data Processing
Data Downloads
Abbreviations
References Cited
 

Introduction

The U.S. Geological Survey (USGS) Coastal and Marine Geology Program has actively collected geophysical and sedimentological data in the northern Gulf of Mexico for several decades, including shallow subsurface data in the form of high-resolution seismic-reflection profiles (HRSP). Prior to the mid-1990s most HRSP data were collected in analog format as paper rolls of continuous profiles up to 25 meters (m) long. A large portion of this data resides in a single repository with minimal metadata. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) currently holds 13 major geophysical surveys from the northern Gulf of Mexico in its paper repository. A conservative estimate of 2,000 line-kilometers (km) of data is available. Paper copies of data are difficult and expensive to duplicate and share with other facilities, and cannot be analyzed using standard geographic information system (GIS) and interpretative software. Conversion of this data into a usable digital format is necessary to archive the geologic information that otherwise might be lost, requiring additional redundant and very expensive marine-geophysical surveys. The USGS National Geological and Geophysical Data Preservation Program (NGGDPP, http://datapreservation.usgs.gov) addresses the need to preserve, catalog, and provide access to geological and geophysical data for scientific research and economic development. In addition to the current efforts under the NGGDPP, four geophysical investigations from the 1980s and 1990s were previously archived through a preservation project in collaboration with the Bureau of Ocean Energy Management (Harrison and others, 2007; Sanford and others, 2009a, b, c).

The USGS SPCMSC scans its analog HRSP holdings using a large-format continuous scanner. The analog to digital conversion process used for this report is similar to the processes used previously in Harrison and others (2007) and Sanford and others (2009a, b, c). The digital files are converted into Tagged Image File Format (TIFF) for standard accessibility by raster image processors. The TIFF images are also converted to the Society of Exploration Geophysicists (SEG-Y) file format. This standard non-proprietary format is the accepted industry standard for seismic data, and can be accessed by all major seismic data processing and interpretation systems. To accompany the HRSP, navigation and metadata files are generated for use in GIS database and Internet Message Access Protocol (IMAP) services, and included in USGS data archives.

The northern Gulf of Mexico is a passive continental margin, where minimal structural change to the shallow stratigraphy has occurred during the last few thousand years (Anderson and others, 2004). Therefore, subsurface data collected from this environment for the purposes of geologic assessment can be considered useful in perpetuity. The geologic information collected by the USGS in the northern Gulf of Mexico remains a valuable resource for sea floor and stratigraphic investigations, and is continuously revisited by researchers interested in Holocene and recent earth processes. For example, decades-old geologic data is commonly used in sediment resource studies in coastal Louisiana (for example, Kindinger and others, 2001; Kulp and others, 2002; Rogers and others, 2009) and previously collected datasets across the Mississippi-Alabama shelf have been used in recent geologic-framework assessments (Roberts and others, 2004; Greene and others, 2007; Flocks and others, 2011).

This report describes data collection and processing methods for seismic profiles created from analog boomer seismic-reflection data collected during three surveys (Erda 90-1_HC, Erda 90-1_PBP, and Erda 91-3) in 1990 and 1991 (table 1).

Table 1.  Survey acquisition characteristics for datasets described in this report. [Abbreviations: HC, Hancock County; LORAN, Long Range Navigation; PBP, Petit Bois Pass]
Survey name Date Geographic area Lead investigator Vessel Approximate line-kilometers Equipment type Power (high/low)
(hertz)
Sweep
(milliseconds)
Fire
(milliseconds)
Sample rate
(milliseconds)
Erda 90-1_HC June 4–6, 1990 Hancock County, Mississippi Sound Jack Kindinger R/V Erda 22.45 Geopulse, LORAN 5,000/700 125 250 0.2–1.4
Erda 90-1_PBP June 8–9, 1990 Petit Bois Pass, Mississippi Sound Jack Kindinger R/V Erda 97.82 Geopulse, LORAN 5,000/700 125 250 0.2–1.4
Erda 91-3 September 12–23, 1991 Mississippi Sound Jack Kindinger R/V Erda 322.82 Geopulse, LORAN 3,000/300 125 250 0.3–3

The seismic data were collected using a single-channel Huntec boomer/benthos hydrophone system with Ocean Research Equipment (ORE) Geopulse power supply. The system consists of an electromagnetic sound source mounted on a catamaran sled towed behind the vessel at the water surface. The signal emitted from the sound source is received by a 5-m-long hydrophone streamer towed alongside the sled. The received signal is processed into response amplitudes via a topside computer running the acquisition software; the settings varied by cruise. The seismic data were printed onto paper rolls as two-dimensional profiles representing track length and depth (time). Geographic positioning of the system was collected using a long range navigation (LORAN) system and annotated onto the paper copies.

This report, along with the accompanying USGS data release (Bosse and others, 2017), serves as an archive of digitized boomer seismic-reflection data collected from the Research Vessel (R/V) Erda during two cruises (Erda 90-1 and Erda 91-3) from the northern Gulf of Mexico in 1990 and 1991. Data products, including scanned images of the analog paper records, converted SEG-Y files (with time stamps, shotpoints, and navigation data), cruise navigation data, and GIS data files with accompanying formal Federal Geographic Data Committee (FGDC) metadata can be downloaded from Bosse and others (2017).

Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/ds/1047/ds1047_intro.html
Page Contact Information: Contact USGS
Page Last Modified: Wednesday, April 19, 2017, 02:30:34 PM