Reprocessed multichannel seismic-reflection (MCS) data from USGS field activity T-1-96-SC collected in San Diego Bay, California in 1996
This data release presents reprocessed multichannel seismic-reflection (MCS) data that was originally collected in 1996 in partnership with the California Division of Mines and Geology and Caltrans as part of a seismic hazard assessment of the Coronado Bridge in San Diego Bay, California. The original survey collected 130 km of data with a 14-cubic inch sleeve-gun (airgun) source, a 24-channel streamer, and 3.125 m shot spacing. Reprocessed profiles show increased data resolution, with data recorded to 750 ms two-way-travel-time, and interpretable data down to about 400 m.
Additional information about the field activities from which these data were derived is available online at:
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Singleton, Drake M., Brothers, Daniel S., Kluesner, Jared W., and Sliter, Ray W., 20210518, Reprocessed multichannel seismic-reflection (MCS) data from USGS field activity T-1-96-SC collected in San Diego Bay, California in 1996: data release DOI:10.5066/P93Z2LYJ, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.0001
Ordinates (y-coordinates) are specified to the nearest 0.0001
Planar coordinates are specified in Meter
The horizontal datum used is D WGS 1984.
The ellipsoid used is WGS 1984.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257223563.
Depth_Datum_Name:local surface Depth_Resolution:0.5 Depth_Distance_Units:two-way travel time Depth_Encoding_Method:attribute values
Data were reprocessed as part of an effort to investigate faulting in south San Diego Bay. Data were used to characterize fault structure, changes in sub-surface stratigraphy, and investigate recency of faulting. Reprocessing scheme included applying a linear moveout, f-k filter, velocity analysis, normal moveout, water bottom mute, stacking, and time migration. These data and information are intended for science researchers, students from elementary through college, policy makers, and general public.
The original survey collected 130 km of MCS lines with a 14-cubic inch sleeve-gun (airgun) source, 24-channel streamer, and 3.125 m shot spacing. The original MCS data were stored as 12-fold common-depth-point gathers with 3.125 m bin spacing. Following transcribing of profiles to modern digital format, the originals SEG-Y files were reprocessed through the Shearwater Reveal software package. The original 24-trace shot gathers were sampled at 250 ms with a total length of 0.75 s. Linear moveout and f-k filters were applied to shot gathers to reduce linear coherent noise and energy from refracted arrivals at longer offsets, which were especially prevalent in shallow San Diego Bay and in portions of the bay proximal to large cement structures such as Naval docks. Next, shot gathers were sorted into common-mid-point (CMP) gathers using a 3.125-m bin spacing (12-fold). Velocity analysis was performed every 100 CMPs by maximizing semblance for supergathers constructed using 15 CMPs, and the resulting velocity models were used to apply normal moveout corrections (NMO). Following NMO corrections, water-bottom and stretch-mutes were applied, and the traces were stacked. Lastly, Stolt migration was applied to stacked sections using a constant velocity of 1600 m/s. Navigation is presented in UTM zone 11N in header bytes 73/77 and in 81/85.
Date: 23-Aug-2021 (process 2 of 2)
Corrected typo in DOI URL in onlink tag of metadata. No data were changed. (email@example.com)
How accurate are the geographic locations?
The original survey lines and navigation from 1996 were stored on magnetic tape files that were destroyed in a warehouse fire. The reprocessed profiles in this dataset therefore did not include navigation data in the SEG-Y header. To overcome this, the original trackline map was georeferenced and individual profiles digitized. The total length of these profiles was divided by the 3.125 m gather spacing to produce the profile navigation. As a result of the georeferencing and uncertainty in profile locations on the original figure, the final locations of some profiles may carry a location error of ~10-100 m. Despite this uncertainty, a comparison of previously mapped features in San Diego Bay shows good agreement in the reprocessed MCS lines presented in this dataset.
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey, California Division of Mines and Geology, and Caltrans as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes.
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What's the catalog number I need to order this data set?T-1-96-SC_SDBay_reproc_mcs.zip contains reprocessed sub-bottom (SEG-Y) data collected during USGS field activity T-1-96-SC. The data are divided up and presented by navigation line, as reflected in the individual file names.
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.
Use of SEG-Y data requires specialized software, such as Reveal by Shearwater Geophysical; ProMax and Seisworks by Landmark Geophysical; FOCUS and SeisX by Paradigm Geophysical; SPW by Parallel Geoscience; VISTA by Seismic Image Software; SeiSee by Dalmorneftegeophysica (DMNG); amongst others.