Metadata:
Identification_Information:
Citation:
Citation_Information:
Originator: Janet T. Watt
Originator: Victoria E. Langenheim
Originator: Lydia M. Staisch
Publication_Date: 20250403
Title: Detailed aeromagnetic survey point data of the Trinidad Area, California
Geospatial_Data_Presentation_Form: comma-delimited text
Series_Information:
Series_Name: data release
Issue_Identification: DOI:10.5066/P13SZBH7
Publication_Information:
Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California
Publisher: U.S. Geological Survey
Online_Linkage: https://doi.org/10.5066/P13SZBH7
Larger_Work_Citation:
Citation_Information:
Originator: Janet T. Watt
Originator: Victoria E. Langenheim
Originator: Lydia M. Staisch
Publication_Date: 2025
Title: Detailed Aeromagnetic Survey of the Trinidad Area, California
Series_Information:
Series_Name: data release
Issue_Identification: DOI:10.5066/P13SZBH7
Publication_Information:
Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California
Publisher: U.S. Geological Survey
Other_Citation_Details: Suggested Citation: Watt, J.T., Langenheim, V.E., and Staisch, L.M., 2025, Detailed aeromagnetic survey of the Trinidad Area, California: U.S. Geological Survey data release, https://doi.org/10.5066/P13SZBH7.
Online_Linkage: https://doi.org/10.5066/P13SZBH7
Description:
Abstract: This data release provides access to point measurement data from a low-altitude, aeromagnetic survey of a part of northwestern California. The survey extends west of the Klamath Mountains across the Pacific Ocean coastline over the continental shelf and covers the towns of Crescent City, Trinidad, Fortuna, Eureka, Arcata, and McKinleyville. Data were acquired during the summer and fall of 2024 by Xcalibur Multiphysics working under contract to the Yurok Tribe and under supervision of the U.S. Geological Survey. Total magnetic field values were acquired using a fixed-wing aircraft flown at a target elevation of 305 meters (m) above terrain and along flight lines and tie lines spaced 600 m and 6000 m apart, respectively. Flight lines were directed northeast-southwest; tie lines were directed northwest-southeast. A total of 13,134 line-kilometers were acquired.
Purpose: These data were acquired to support earthquake hazard investigations and geologic mapping of the greater Trinidad area of northwestern California. The primary focus was to map continuity and geometry of faults and folds from the town of Fortuna north to Smith River.
Supplemental_Information: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20240828
Ending_Date: 20240927
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -124.5260
East_Bounding_Coordinate: -123.7210
North_Bounding_Coordinate: 41.9360
South_Bounding_Coordinate: 40.5660
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:07514fbf-8128-44bd-bc0e-da9bd5a51faf
Theme:
Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: substrate
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation
Theme:
Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords
Theme_Keyword: continental margin
Theme_Keyword: magnetic field observations
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: magnetic field (earth)
Theme_Keyword: magnetometer measurement
Theme_Keyword: aeromagnetic surveying
Theme_Keyword: crust (earth)
Theme_Keyword: neotectonic processes
Theme_Keyword: earthquakes
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Coastal and Marine Hazards and Resources Program
Theme_Keyword: CMHRP
Theme_Keyword: Pacific Coastal and Marine Science Center
Theme_Keyword: PCMSC
Theme_Keyword: magnetic anomaly
Place:
Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: State of California
Place_Keyword: Trinidad
Place_Keyword: Fortuna
Place_Keyword: McKinleyville
Place_Keyword: Arcata
Place_Keyword: Eureka
Place_Keyword: Orick
Place_Keyword: Crescent City
Access_Constraints: No access constraints. Please see 'Distribution Info' for details.
Use_Constraints: 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 as the originator(s) of the dataset and in products derived from these data. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: PCMSC Science Data Coordinator
Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Address:
Address_Type: mailing address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Country: US
Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov
Data_Set_Credit: The Trinidad aeromagnetic survey was conducted by Xcalibur Multiphysics, working under contract with the Yurok Tribe and under supervision of the U.S. Geological Survey. David Miles was project manager and data processing was done by Fabian Linares and Tonia Bojkova. The Yurok Tribe coordinated flight and access permissions.
Cross_Reference:
Citation_Information:
Originator: Alken, P.
Originator: Thébault, E.
Originator: Beggan, C.D.
Originator: Amit, H.
Originator: Aubert, J.
Originator: Baerenzung, J.
Originator: Bondar, T.N.
Originator: Brown, W.J.
Originator: Califf, S.
Originator: Chambodut, A.
Originator: Chulliat, A.
Originator: Cox, G.A.
Originator: Finlay, C.C.
Originator: Fournier, A.
Originator: Gillet, N.
Originator: Grayver, A.
Originator: Hammer, M.D.
Originator: Holschneider, M.
Originator: Huder, L.
Originator: Hulot, G.
Originator: Jager, T.
Originator: Kloss, C.
Originator: Korte, M.
Originator: Kuang, W.
Originator: Kuvshinov, A.
Originator: Langlais, B.
Originator: Léger, J.-M.
Originator: Lesur, V.
Originator: Livermore, P.W.
Originator: Lowes, F.J.
Originator: Macmillan, S.
Originator: Magnes, W.
Originator: Mandea, M.
Originator: Marsal, S.
Originator: Matzka, J.
Originator: Metman, M.C.
Originator: Minami, T.
Originator: Morschhauser, A.
Originator: Mound, J.E.
Originator: Nair, M.
Originator: Nakano, S.
Originator: Olsen, N.
Originator: Pavón-Carrasco, F.J.
Originator: Petrov, V.G.
Originator: Ropp, G.
Originator: Rother, M.
Originator: Sabaka, T.J.
Originator: Sanchez, S.
Originator: Saturnino, D.
Originator: Schnepf, N.R.
Originator: Shen, X.
Originator: Stolle, C.
Originator: Tangborn, A.
Originator: Tøffner-Clausen, L.
Originator: Toh, H.
Originator: Torta, J.M.
Originator: Varner, J.
Originator: Vervelidou, F.
Originator: Vigneron, P.
Originator: Wardinski, I.
Originator: Wicht, J.
Originator: Woods, A.
Originator: Yang, Y.
Originator: Zeren, Z.
Originator: Zhou, B.
Publication_Date: 2021
Title: International Geomagnetic Reference Field: the thirteenth generation
Other_Citation_Details: Alken, P., Thébault, E., Beggan, C. D., Amit, H., Aubert, J., Baerenzung, J., Bondar, T. N., Brown, W. J., Califf, S., Chambodut, A., Chulliat, A., Cox, G. A., Finlay, C. C., Fournier, A., Gillet, N., Grayver, A., Hammer, M. D., Holschneider, M., Huder, L., Hulot, G., Jager, T., Kloss, C., Korte, M., Kuang, W., Kuvshinov, A., Langlais, B., Léger, J.-M., Lesur, V., Livermore, P. W., Lowes, F. J., Macmillan, S., Magnes, W., Mandea, M., Marsal, S., Matzka, J., Metman, M. C., Minami, T., Morschhauser, A., Mound, J. E., Nair, M., Nakano, S., Olsen, N., Pavón-Carrasco, F. J., Petrov, V. G., Ropp, G., Rother, M., Sabaka, T. J., Sanchez, S., Saturnino, D., Schnepf, N. R., Shen, X., Stolle, C., Tangborn, A., Tøffner-Clausen, L., Toh, H., Torta, J. M., Varner, J., Vervelidou, F., Vigneron, P., Wardinski, I., Wicht, J., Woods, A., Yang, Y., Zeren, Z., and Zhou, B., 2021, International Geomagnetic Reference Field: the thirteenth generation: Earth, Planets and Space, v. 73, n. 49, https://doi.org/10.1186/s40623-020-01288-x
Online_Linkage: https://doi.org/10.1186/s40623-020-01288-x
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Magnetic field values were measured with a Scintrex CS-3 cesium-vapor magnetometer, with a resolution of 0.002 nanotesla (nT). Total magnetic field values were measured at 0.05-sec intervals. Magnetic signals caused by aircraft motion and heading were compensated using a Billingsley TMF 100 Triaxial (X,Y,Z) fluxgate magnetometer mounted in the tail stinger. Prior to the survey, the aircraft and its instrumentation were put through a series of roll, pitch, and yaw maneuvers to form a model of the aircraft's magnetic characteristics. These maneuvers were performed in a region of low magnetic gradient and high altitude to minimize influence of magnetic geologic sources and to develop a compensation correction for the survey data.
Two stationary magnetometers were deployed within the survey area at McKinleyville to monitor and subsequently correct for diurnal magnetic field and magnetic storm variations. The base magnetometers were GEM Systems magnetometers sampled at 1-sec intervals.
Navigation was accomplished with a GPS system mounted on the tail of the aircraft. The NovAtel Model OEMV-2 receiver has a real-time accuracy of 1.5 meters (L1), sampled at 0.5-sec intervals.
Logical_Consistency_Report: This dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
Completeness_Report: This data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report: Three-dimensional positions were determined with ta NovAtel OEMV-2 receiver with an antenna mounted on the tail of the aircraft. Realtime accuracy is estimated to be 1.5 m.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report: Altitude was determined with the same GPS systems and a Bendix King KRA 10 radar altimeter. Altitude accuracy is estimated to be within 2 to 3 m.
Lineage:
Process_Step:
Process_Description: While in the field, the base-station magnetometers located in McKinleyville were monitored for magnetic field variations in excess of contract specifications. In the airborne magnetics, a fourth difference was calculated on the compensated total magnetic field in order to verify noise level and identify and remove discrete spikes. Data were corrected for the lag in time between the onboard GPS system and the tail-mounted magnetometer. Uncompensated and compensated total magnetic field profiles were monitored on a daily basis to assess compensation effectiveness. Readings from the two base stations were used to calculate and remove diurnal variations. Please see contractor report (2400075_YurokTribe_Tech_Report_508.pdf) for additional details.
Process_Date: 20241101
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Janet T. Watt
Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Position: Research Geophysicist
Contact_Address:
Address_Type: mailing address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Country: US
Contact_Voice_Telephone: 831-460-7565
Contact_Electronic_Mail_Address: jwatt@usgs.gov
Process_Step:
Process_Description: Flight and tie lines were "levelled" using the statistical distribution of total field differences at each flight-line-tie-line crossing. The goal was to obtain the smoothest possible correction model for each line that minimizes the difference in magnetic field measured at each tie-line-flight-line crossing. Finally, the full International Geomagnetic Reference Field (IGRF, Alken and others, 2021), updated to the date of the survey, was subtracted from the measured, corrected total magnetic intensity, thus providing the residual magnetic intensity.
Process_Date: 20241101
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Point
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Point
Point_and_Vector_Object_Count: 3337738
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 0.00001
Longitude_Resolution: 0.00001
Geographic_Coordinate_Units: Decimal degrees
Geodetic_Model:
Horizontal_Datum_Name: World Geodetic System 1984 (WGS 84)
Ellipsoid_Name: WGS_1984
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257223563
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: mean sea level
Altitude_Resolution: 5
Altitude_Distance_Units: meters
Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: Trinidad_aeromag.csv
Entity_Type_Definition: table containing attribute information associated with magnetic data set
Entity_Type_Definition_Source: Producer defined
Attribute:
Attribute_Label: date
Attribute_Definition: Flight date
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 20240828
Range_Domain_Maximum: 20240927
Attribute_Units_of_Measure: YYYYMMDD Universal Time Coordinated (UTC)
Attribute:
Attribute_Label: diurnal
Attribute_Definition: Diurnal correction
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -51.232
Range_Domain_Maximum: 36.260
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: dtm
Attribute_Definition: Digital terrain model elevation (3DEP), referenced to mean sea level (meters)
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.000
Range_Domain_Maximum: 1322.869
Attribute_Units_of_Measure: meter
Attribute:
Attribute_Label: easting_WGS84
Attribute_Definition: Easting value (UTM10N, WGS84)
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 370620.554
Range_Domain_Maximum: 439773.354
Attribute_Units_of_Measure: meter
Attribute:
Attribute_Label: fid
Attribute_Definition: Fiducial (seconds since midnight)
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 55334.05
Range_Domain_Maximum: 94504.20
Attribute_Units_of_Measure: Seconds since beginning of UTC day at start of line
Attribute:
Attribute_Label: flight
Attribute_Definition: Flight number
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 9
Range_Domain_Maximum: 23
Attribute_Units_of_Measure: integer
Attribute:
Attribute_Label: Flux_X
Attribute_Definition: Fluxgate magnetometer X component value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -48701.734
Range_Domain_Maximum: -29421.870
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: Flux_Y
Attribute_Definition: Fluxgate magnetometer Y component value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -25681.289
Range_Domain_Maximum: 27615.556
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: Flux_Z
Attribute_Definition: Fluxgate magnetometer Z component value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -37331.591
Range_Domain_Maximum: 31020.602
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: gpsz
Attribute_Definition: Aircraft GPS elevation, referenced to mean sea level (meters)
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 238.830
Range_Domain_Maximum: 1607.430
Attribute_Units_of_Measure: meter
Attribute:
Attribute_Label: height
Attribute_Definition: Aircraft height above above surface from digital elevation model
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 191.915
Range_Domain_Maximum: 1322.758
Attribute_Units_of_Measure: meter
Attribute:
Attribute_Label: igrf
Attribute_Definition: International geomagnetic reference field (IGRF) value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 48766.773
Range_Domain_Maximum: 49602.675
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: latitude_WGS84
Attribute_Definition: Aircraft latitude value in WGS84
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 40.56619
Range_Domain_Maximum: 41.93837
Attribute_Units_of_Measure: degrees
Attribute:
Attribute_Label: line
Attribute_Definition: Flight line number
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 10010
Range_Domain_Maximum: 90210
Attribute_Units_of_Measure: integer
Attribute:
Attribute_Label: longitude_WGS84
Attribute_Definition: Aircraft longitude value in WGS84
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -124.52850
Range_Domain_Maximum: -123.71929
Attribute_Units_of_Measure: degrees
Attribute:
Attribute_Label: mag_comp
Attribute_Definition: Compensated total magnetic field value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 48708.471
Range_Domain_Maximum: 50757.584
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: mag_diu
Attribute_Definition: Diurnal and lag corrected total magnetic field value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 48697.039
Range_Domain_Maximum: 50772.720
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: mag_raw
Attribute_Definition: Uncompensated total magnetic field value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 48698.268
Range_Domain_Maximum: 50741.332
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: mag_rmi
Attribute_Definition: Final residual magnetic intensity value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -410.827
Range_Domain_Maximum: 1333.362
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: mag_tmi
Attribute_Definition: Final total magnetic intensity value
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 48696.157
Range_Domain_Maximum: 50781.935
Attribute_Units_of_Measure: nanotesla
Attribute:
Attribute_Label: northing_WGS84
Attribute_Definition: Aircraft northing value (UTM10N, WGS84)
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 4491493.189
Range_Domain_Maximum: 4643535.896
Attribute_Units_of_Measure: meter
Attribute:
Attribute_Label: time_ssm
Attribute_Definition: Elapsed time in seconds since midnight
Attribute_Definition_Source: Producer defined
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.00
Range_Domain_Maximum: 86399.90
Attribute_Units_of_Measure: seconds
Overview_Description:
Entity_and_Attribute_Overview: The data in this release are as provided to the USGS by the contractor, Xcalibur Multiphysics. The file trinidad_aeromag.csv provides point measurements along each flight line and tie line in comma-separated-value (CSV) format. Additional information is available in the accompanying document 2400075_YurokTribe_Tech_Report_508.pdf.
Entity_and_Attribute_Detail_Citation: Airborne survey procedures, quality control, and data processing methods are described in the document 2400075_YurokTribe_Tech_Report_508.pdf, provided by the contractor. Point data are available in the file Trinidad_aeromag.csv provided by the contractor and in CSV format.
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey - CMGDS
Contact_Address:
Address_Type: mailing and physical
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov
Resource_Description: These data are available in csv format (Trinidad_aeromag.csv) accompanied by CSDGM FGDC-compliant metadata
Distribution_Liability: 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.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: comma-delimited text
Format_Version_Number: Notepad, 11.2412.16.0
Format_Information_Content: File contains table in .csv format
File_Decompression_Technique: No compression applied
Transfer_Size: 856.1
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: https://doi.org/10.5066/P13SZBH7
Access_Instructions: Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Magnetic Data section.
Fees: None
Technical_Prerequisites: Data can be viewed with any text reader software.
Metadata_Reference_Information:
Metadata_Date: 20250403
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: PCMSC Science Data Coordinator
Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Address:
Address_Type: mailing address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Country: US
Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998