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USGS Coastal and Marine Geology Program

Field Activity Details for field activity L490SC

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AKA: none

Other ID: L-4-90-SC

Status: Completed


Funding Program(s):

Principal Investigator(s): Bob Bohannon, Steve Eittreim

Affiliate Investigator(s):

Information Specialist(s):

Data Type(s): Seismics: Multichannel, Seismics: Air Gun / Water Gun, Seismics: Sub Bottom Profiler, Sonar: Single Beam, Seismics: Sonobuoy, Electro-Magnetic: Gravity, Electro-Magnetic: Magnetics, Location-Elevation: Navigation

Scientific Purpose/Goals:


Start Port/Location: Santa Cruz, CA

End Port/Location: Redwood City, CA

Start Date: 1990-05-09

End Date: 1990-05-25

Equipment Used: 24channel, airgun, 3.5khz, 12khz, sonobuoy, gravity, magnetics, GPS, integratednavigation, RhoRho, airgunmonitor

Information to be Derived:

Summary of Activity and Data Gathered:

Staff: Al McClenaghan, Bette Lu, Bill Lafleur, Bill Robinson, Corky Ozanne, Dave Hogg, Hal Williams, Jean Riordan, Kaye Kinoshita, Patrick Hart, Jonathan Childs

Affiliate Staff:
Calvin Lee (U.S.C.) - Watchstander
Chris Sorlien (U.C.S.B.) - Watchstander
Larry Busch (S.D.S.U.) - Navigator
Mark Legg (S.D.S.U.) - Watchstander


Staff information imported from InfoBank
Al McClenaghan - Ship Captain
Bette Lu Krause - Chief Mate
Bill Lafleur - Chief Engineer
Bill Robinson - Electrical Engineer
Bob Bohannon - Chief Scientist
Calvin Lee (U.S.C.) - Watchstander
Chris Sorlien (U.C.S.B.) - Watchstander
Corky Ozanne - Mechanical Technician
Dave Hogg - Electronics Technician
Hal Williams - Mechanical Technician
Jean Riordan - Navigator
Jon Childs - Geophysicist
Kaye Kinoshita - Navigator
Larry Busch (S.D.S.U.) - Navigator
Mark Legg (S.D.S.U.) - Watchstander
Pat Hart - Geophysicist
Steve Eittreim - Chief Scientist


Southern California

North: 36.97062 South: 31.19093 West: -122.012 East: -117.35716


photo of Samuel Phillips Lee
Samuel Phillips Lee


Alongi, T., Balster-Gee, A.F., Kluesner, J.W., and Sliter, R.W., 2023, Reprocessed multichannel seismic-reflection data acquired offshore Southern California during USGS field activity L-4-90-SC: U.S. Geological Survey data release,

Bird, K.J., Childs, J.R., Taylor, D.J., and Sorlien, C.C., 1991, Seismic-reflection studies, offshore Santa Maria Province, California: American Association of Petroleum Geologists Bulletin, v. 75 no. 2, pp. 357–358.

Bohannon, R.G., and Geist, E.L., 1992, Tectonostratigraphy and Neogene extensional tectonism on part of the California continental borderland; a seismic-reflection perspective, in Carter, L.M.H., ed., USGS research on energy resources 1992; program and abstracts: U. S. Geological Survey Circular 1074, pp. 13–13.

Bohannon, R.G., Eittreim, S.L., and Childs, J.R., 1990, Cruise Report of R/V S.P. Lee, Leg 4, 1990, California continental borderland: U.S. Geological Survey Open-File Report 90-0502, 10 p.,

Bohannon, R.G., Eittreim, S.L., Childs, J.R., Geist, E.L., Legg, M.R., Lee, C., Sorlien, C.C., and Busch, L., 1990, A seismic-reflection study of the California continental borderland: American Geophysical Union Eos, Transactions, v. 71 no. 43, pp. 1631–1631.

Bohannon, R.G., Geist, E.L., and Sorlien, C., 1993, Miocene extensional tectonism on California continental borderland between San Clemente and Patton Escarpment: American Association of Petroleum Geologists Bulletin, v. 77 no. 4, pp. 691–691.

Henyey, T.L., Okaya, D.A., Robertson, M., Li, Y.G., Day, S., Davis, P.M., Martin, A., and Bohannon, R.G., 1990, Wide-angle seismic imaging in the Peninsular Ranges, Southern California, using marine airgun sources recorded at fixed-site receivers: , American Geophysical Union Fall Meeting Abstracts page 1631.

Li, Y.-G., Henyey, T.L., Okaya, D.A., Davis, P.M., Day, S.M., and Bohannon, R.G., 1993, Offshore-to-onshore seismic recording in the Southern California borderlands-Peninsular Ranges: , American Geophysical Union Fall Meeting Abstracts page 445.

Ryan, H.F., Legg, M.R., Conrad, J.E., and Sliter, R.W., 2009, Recent faulting in the Gulf of Santa Catalina; San Diego to Dana Point; Earth science in the urban ocean; the Southern California continental borderland, in Lee, H.J., and Normark, W.R., eds., Earth Science in the Urban OceanâThe Southern California Continental Borderland: Geological Society of America Special Paper 454, pp. 291–315, doi: 10.1130/2009.2454(4.2).


FAN L490SC has data viewable in the GeoMappApp/Virtual Ocean applications. To view this data in these applications go to and See the instructions for locating USGS data in these applications. You can also view the imagery created from the SEGY data at

Data Acquired

Survey EquipmentSurvey InfoData Type(s)Data Collected
24channel --- Multichannel
Raw seismic shot point data l-4-90-sc.400
Raw seismic shot point data l-4-90-sc.400-_10
Raw seismic shot point data l-4-90-sc.401
Raw seismic shot point data l-4-90-sc.401_051
Raw seismic shot point data l-4-90-sc.400-_100spt
Raw seismic shot point data l-4-90-sc.401_052 (Provisional best file)
Survey information
Multichannel data (stack data) (Download SEG-Y files from National Archive of Marine Seismic Surveys (NAMSS))
Multichannel data (mig) (Download SEG-Y files from National Archive of Marine Seismic Surveys (NAMSS))
Reprocessed multichannel seismic reflection data (Multichannel seismic (MCS) data were collected by the U.S. Geological Survey (USGS) in 1990 in the California Continental Borderland (USGS field activity L490SC). In 2021 these data were reprocessed to improve accuracy and resolvability of geologic structures and fault systems of California's continental margin.)
airgun --- Air Gun / Water Gun
Survey information
3.5khz --- Sub Bottom Profiler
L-4-90-SC_154294/bathy (scanned microfilm)
Survey information
12khz --- Single Beam
Raw depth (bathymetry) data l-4-90-sc.300
Raw depth (bathymetry) data l-4-90-sc.300_051 (Provisional best file)
Survey information
NGDC MGD77 data - bathy
sonobuoy --- Sonobuoy
Survey information
gravity --- Gravity
Raw gravity data from digital meter l-4-90-sc.102_051 (Provisional best file)
Gravity lines start/end control data l-4-90-sc.130
Survey information
Raw gravity data from digital meter l-4-90-sc.102
NGDC MGD77 data - gravity
Gravity land tie data l-4-90-sc.140
Free Air Anomaly data l-4-90-sc.160
magnetics --- Magnetics
Raw magnetics data l-4-90-sc.201
Raw magnetics data l-4-90-sc.201_051
Edited magnetics data l-4-90-sc.220
NGDC MGD77 data - Magnetics
Edited magnetics data l-4-90-sc.221_051 (Provisional best file)
GPS --- Navigation
Global positioning system (GPS) data l-4-90-sc.060
Survey information
integratednavigation --- Navigation
Integrated navigation (SINS) data l-4-90-sc.050
Best file with nav in ArcInfo E00 format
Integrated navigation (SINS) data l-4-90-sc.051 (Provisional best file)
Integrated navigation (SINS) data l-4-90-sc.051_degree
Integrated navigation (SINS) data l-4-90-sc.052
Survey information
RhoRho --- Navigation
Survey information
Loran C data l-4-90-sc.030
airgunmonitor --- Air Gun / Water Gun
Survey information
L-4-90-SC_154294/SCAG (data on FAD)

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