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General Information

Data Type

Singlechannel Seismic

Data Acquisition System

Chirp

Contributor

Pacific Coastal and Marine Science Center

Dates

Started on June 1, 2010, and ended on June 12, 2010.

Number of Tracklines

51

Distance Shot

570 km

Description

Chirp seismic-reflection data of field activity S-12-10-SC: Oceanside to La Jolla, offshore southern California from 2010-06-01 to 2010-06-12

Purpose

This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey is area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 chirp subbottom profiler. Subbottom acoustic penetration spanned tens to about 50 meters, variable by location.

Notes

Citation: Sliter, R.W., Conrad, J.E., Ryan, H.F., and Triezenberg, P.J., 2017, Chirp seismic-reflection data of field activity S-12-10-SC: Oceanside to La Jolla, offshore southern California from 2010-06-01 to 2010-06-12: U.S. Geological Survey data release, doi:10.5066/F7VD6WMM

Geographic Features

Southern California

Dataset Information

Processed Methods

Seismic Reflection

Processed Data Classes

Other

Data File Formats

SEG-Y

Embedded Navigation

Yes

Data Class

Compilation

Seismic Data Provenances

Digitally Acquired Digital SEG

Data Media

Online

Processing

Seismic-reflection data were collected using an Edgetech 512 Chirp subbottom profiling system consisting of a source transducer and an array of receiving hydrophones housed in a 500-lb “fish” towed at a depth of several meters below the sea surface. The swept-frequency “chirp” source signal is between 500 and 4,500 Hz, and data are recorded by hydrophones located on the bottom of the fish. At boat speeds of 4 to 4.5 nm/hour, seismic traces were collected roughly every 1 to 2 meters. The data consist of three-channels, a raw channel, a 90-degree phase-shifted channel and an “amplitude envelope” channel created and transformed internally from the other two channels. The data were recorded in standard SEG-Y 16-bit integer format with Triton Subbottom Logger (SBL) software that merges seismic-reflection data with differential GPS navigation data.

The processed seismic-reflection SEG-Y files consist of the internally transformed amplitude envelope channel corrected for the depth of the fish below the sea surface using Paradigm Geophysical Echos seismic processing software. 1) SEG-Y channel with sequence number “1” was written to a SEG-Y file; 2) The fish depth header word was read and converted from millimeters to two-way travel time to create a fish-depth static value; and 3) The fish depth static was applied to the data to correct for the vertical up and down movement of the Chirp fish and a final processed SEG-Y was output.

Navigation Information

Datum

World Geodetic System 1984 (WGS84)

Location

Tracklines 51 total

Name Length (km) First SP Last SP First CDP Last CDP
OSC-01 19 1 7,369 1 7,369
OSC-02 19 1 7,329 1 7,329
OSC-03 20 1 8,287 1 8,287
OSC-04 21 1 7,495 1 7,495
OSC-05 20 1 8,393 1 8,393
OSC-06 19 1 7,044 1 7,044
OSC-07 20 1 8,470 1 8,470
OSC-08 18 1 6,646 1 6,646
OSC-09 19 1 7,893 1 7,893
OSC-10 14 1 4,917 1 4,917
OSC-11 14 1 5,906 1 5,906
OSC-12 18 1 5,849 1 5,849
OSC-13 8 1 12,799 1 12,799
OSC-13A 5 1 2,668 1 2,668
OSC-13B 4 1 1,302 1 1,302
OSC-14 8 1 11,773 1 11,773
OSC-14A 4 1 2,134 1 2,134
OSC-14B 4 1 1,327 1 1,327
OSC-15 26 1 7,700 1 7,700
OSC-16 9 1 2,431 1 2,431
OSC-17 23 1 7,440 1 7,440
OSC-17A 6 1 2,018 1 2,018
OSC-18 1 1 493 1 493
OSC-18A 2 1 1,801 1 1,801
OSC-18B 6 1 3,160 1 3,160
OSC-18C 6 1 2,075 1 2,075
OSC-19 8 1 2,455 1 2,455
OSC-19A 7 1 3,237 1 3,237
OSC-19B 3 1 4,968 1 4,968
OSC-20 12 1 3,934 1 3,934
OSC-21 11 1 3,098 1 3,098
OSC-22 1 1 444 1 444
OSC-22A 18 1 5,931 1 5,931
OSC-23 7 1 1,920 1 1,920
OSC-24 6 1 2,042 1 2,042
OSC-25 7 1 1,958 1 1,958
OSC-26 6 1 1,693 1 1,693
OSC-27 6 1 1,930 1 1,930
OSC-28 6 1 1,790 1 1,790
OSC-29 9 1 2,699 1 2,699
OSC-39 34 1 9,933 1 9,933
OSC-40 8 1 2,179 1 2,179
OSC-41 8 1 2,256 1 2,256
OSC-42 8 1 2,069 1 2,069
OSC-43 8 1 2,747 1 2,747
OSC-44 10 1 2,960 1 2,960
OSC-45 7 1 2,127 1 2,127
OSC-46 7 1 1,927 1 1,927
OSC-47 19 1 7,280 1 7,280
OSC-48 12 1 5,275 1 5,275
OSC-49 9 1 3,442 1 3,442