How can an engineering geologist find an active fault?

Description

This talk will summarize techniques my students and I use to find the ground-surface trace of seismogenic/active faults. It will emphasize the ideas of geoscience to benefit society, the primacy principle of protecting human life/safety, the comingling of basic fieldwork with analysis of geophysical data (relocated earthquake hypocenter data, earthquake focal mechanisms, GPS geodesy, LiDAR-based geomorphic analysis), and the virtue of continuing education throughout a geoscientist's career.

Some Resources

• Topographic maps
  • Access to USGS topographic maps in digital form via TopoView: https://ngmdb.usgs.gov/topoview/viewer/
  • Another source of GeoPDF files of USGS topographic maps: viewer.nationalmap.gov/basic/?basemap=b1&category=ustopo&title=US Topo Download
  • US National Map interactive viewer: https://apps.nationalmap.gov/viewer/
• Geologic maps and maps of active faults
  • National Geologic Map Database: https://ngmdb.usgs.gov/ngmdb/ngmdb_home.html
  • Quaternary Fault and Fold Database of the United States (QFFDBUS): https://www.usgs.gov/natural-hazards/earthquake-hazards/faults
    QFFDBUS interactive map: https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=5a6038b3a1684561a9b0aadf88412fcf
• LiDAR-based digital elevation models
  • OpenTopography.org (it is suggested that you use either Firefox, Chrome, "or another WebGL2 browser" so that you will have full access to the results): https://opentopography.org
    — Video made in support of Cronin's "Intro to Structural Geology" lab, showing an example of acquiring a DEM from OpenTopography: https://youtu.be/hcRqC2bYS14
    • Download the compressed DEM Results (a file called "rasters_sdem.tar.gz")
    • Decompress the file, resulting in a folder named something like "rasters_sdem" and open that folder to see three files with names something like the following: output_hh.asc, output_hh.asc.aux.xml, and output_hh.prj.
    • You can open the file with the .asc tag using a common text editor like TextEdit or BBEdit to examine its contents. You will see six header rows that specify various important information about the datafile (number of columns, number of rows, the UTM coordinates of the lower left corner of the dataset, the horizontal spacing between nodes in the square grid, and the value used to indicate a missing value in the dataset), followed by hundreds or thousands of rows and columns of data. Each datum in that sea of numbers is an elevation above sea level. It is this dataset of elevations that allows us to write computer code to analyze or visualize the ground surface in this area.
    • Close the file, and change the file name to something meaningful to you, and replace the .asc tag of this file with a .dat tag so we can use it in Mathematica codes such as MakeHillshade.nb or the SLAM code SLAMcode20210103.nb.
  • "The Impact of Open Access Lidar Topography" by Emily Zawacki in Lidar Magazine (July 26, 2022), accessible via https://lidarmag.com/2022/07/26/the-impact-of-open-access-lidar-topography/
  • UNAVCO video about LiDAR: https://youtu.be/chSywRqgIGY?list=PLzmugeDoplFM5pPI80wwi3qmtZH99Ism2
  • NEON video about LiDAR: https://www.youtube.com/watch?v=EYbhNSUnIdU&feature=youtu.be
• Recorded modern earthquakes
  • Initial location of hypocenters
    • Bulletin of the International Seismological Centre (ISC): http://www.isc.ac.uk/iscbulletin/
    • NationalEarthquake Information Center (NEIC) earthquake catalog: https://earthquake.usgs.gov/earthquakes/search/
    • Northern California Earthquake Data Center (NCEDC): https://ncedc.org/web-services-home.html
    • Southern California Earthquake Data Center (SCEDC): https://scedc.caltech.edu
      SCEDC earthquake catalogs: https://scedc.caltech.edu/data/eq-catalogs.html
  • Relocation of hypocenters
    • Felix Waldhauser's home page at Lamont: https://www.ldeo.columbia.edu/~felixw/
    • Real-time double-difference earthquake locations for northern California: http://ddrt.ldeo.columbia.edu/DDRT/index.html
    • Double-difference earthquake catalog for Northern California (1984-2011): https://www.ldeo.columbia.edu/~felixw/NCAeqDD/
    • Hauksson et al (2011) Waveform Relocated Earthquake Catalog for Southern California (1981-2022): https://scedc.caltech.edu/data/alt-2011-dd-hauksson-yang-shearer.html
  • Focal mechanisms
    • Focal mechanism primer (Cronin, 2010): https://croninprojects.org/Vince/Course/IntroStructGeol/Focal_mechanism_primer_v4.pdf
      For a more technical treatment, see Jost and Herrmann (1989) or a seismology textbook, e.g., Stein and Wysession (2003), Shearer (1999), Kasahara (1981), Lay and Wallace (1995).
    • Some FM and Moment Tensor data sources
      • USGS National Earthquake Information Center (NEIC):https://neic.usgs.gov/neis/FM/
      • Searchable NEIC databases: https://neic.usgs.gov/neis/sopar/
      • Berkeley Moment Tensor Catalog, accessed via http://seismo.berkeley.edu/mt/
      • SCSN Moment Tensor Catalog: https://service.scedc.caltech.edu/eq-catalogs/CMTsearch.php
        SCSN Focal Mechanism Catalog: https://service.scedc.caltech.edu/eq-catalogs/FMsearch.php
      • Cheng et al (2022), Refined focal mechanism catalog for southern California: https://scedc.caltech.edu/data/alt-2022-cheng.html
      • Global CMT Project: https://www.globalcmt.org/ and https://www.globalcmt.org/CMTsearch.html
      • Bulletin of the International Seismological Centre (ISC): http://www.isc.ac.uk/iscbulletin/
      • National Earthquake Information Center (NEIC) earthquake catalog: https://earthquake.usgs.gov/earthquakes/search/
• Seismo-lineament analysis: https://croninprojects.org/Vince/SLAM/
• GNSS/GPS
  • Site velocity data
    GAGE facility network portal: https://www.unavco.org/instrumentation/networks/networks.html
    Nevada Geodetic Laboratory GPS networks map: http://geodesy.unr.edu/NGLStationPages/gpsnetmap/GPSNetMap.html
  • Estimating current crustal strain from GNSS/GPS velocity data
    • GETSI module "GPS, Strain, and Earthquakes" resources: https://serc.carleton.edu/getsi/teaching_materials/gps_strain/index.html
    • Triangle-strain explanations
      • Primer on infinitesimal strain analysis in 1, 2, and 3-D (revised December 2021): https://croninprojects.org/Vince/Geodesy/GPS_Strain_Primer.pdf (.pdf, 1.3 MB)
      • Algorithm for triangle-strain analysis (revised December 2021): https://croninprojects.org/Vince/Geodesy/TriangleStrainAlgorithm.docx (.pdf, 769 KB)
    • Triangle strain calculators
      • Microsoft Excel version: https://CroninProjects.org/Vince/Geodesy/Calculators/GPS-strain-calculator-20220821.xlsx (Excel 31 kb)
        Video "How to use the Excel spreadsheet that computes crustal strain in a triangle between 3 GPS stations": https://youtu.be/nJJudaorc4w
      • Wolfram Mathematica notebook version that reads input data from a CSV file: https://CroninProjects.org/Vince/Geodesy/Calculators/GPS-strain-calculator-InputCSV-20220822.nb
        — PDF file showing the Mathematica code after a sample run: https://CroninProjects.org/Vince/Geodesy/Calculators/GPS-strain-calculator-InputCSV-20220822.pdf
        — Sample input CSV data file for Truckee-area analysis, NAM14 reference frame: https://CroninProjects.org/Vince/Geodesy/TruckeeAreaGPS-velocities-20220821.csv
      • MatLab version (zip file): https://d32ogoqmya1dw8.cloudfront.net/files/getsi/teaching_materials/gps_strain/gps_strain_calculator_matlab.zip
  • Focal mechanisms as crustal-strain indicators

References

Ashburn, J.A., 2015, Investigation of a lineament that might mark the ground-surface trace of the Dog Valley fault, Truckee area, northern California: Baylor University Geology Department, defended 13 July 2015, accessible via https://CroninProjects.org/Vince/AshburnBSThesis2015.pdf.

Cronin, V.S., 2004, A draft primer on focal mechanism solutions for geologists: Teaching Quantitative Skills in the Geosciences, https://serc.carleton.edu/files/NAGTWorkshops/structure04/Focal_mechanism_primer.pdf

Cronin, V.S., 2008, Finding the mean and 95 percent confidence interval of a set of strike-and-dip or lineation data: Environmental and Engineering Geoscience, v. XIV, no. 2, p. 113-119.

Cronin, V.S., 2014, Seismo-Lineament Analysis Method (SLAM), using earthquake focal mechanisms to help recognize seismogenic faults: Proceedings of the 5th International INQUA meeting on Paleoseismology, Active Tectonics and Archeoseismology (PATA Days), 21-27 September, Busan, South Korea, p. 21-27 September 2014, p. 28-31, ISBN 9791195344109 93450; available via https://CroninProjects.org/Vince/SLAM/CroninINQUA_PATA14.pdf.

Cronin, V.S., Millard, M.A., Seidman, L.E., and Bayliss, B.G., 2008, The Seismo-Lineament Analysis Method [SLAM] for finding seismogenic faults: Environmental and Engineering Geoscience, v. 14, no. 3, p. 199-219.

Fisher, R.A., 1953, Dispersion on a sphere: Proceedings Royal Society, London, v. A217, no. 1130. p. 295-305.

Hobart, C., 2021, Selecting locations for future geophysical surveys in search of the Dog Valley fault using earthquake, LiDAR, and GPS data: MS research, Baylor University, accessible via https://baylor-ir.tdl.org/handle/2104/11697.

Johnson, A.M., Burnham, C.W., Allen, C.R., and Muehlberger, W. [editors], 1990, Richard H. Jahns Memorial Volume -- A selection of papers presented in honor of his memory by his students: Elsevier, 594 p. and 5 plates.

Lindsay, R., 2011, Applying SLAM to recognize seismogenic faults in the Tahoe Basin area of California and Nevada: MS research, Baylor University, accessible via https://baylor-ir.tdl.org/handle/2104/11697.

Logan, J.M., Friedman, M., Higgs, N., Dengo, C., and Shimamoto, T., 1979, Experimental studies of simulated gouge and their application to studies of natural fault zones, in Analysis of actual fault zones in bedrock: U.S. Geological Survey, Open-File Report 79-1239, p. 305-343, accessible via https://pubs.usgs.gov/of/1979/of79-1239/

McCalpin, J.P., [editor], 2009, Paleooseismology [2nd edition]: Academic Press, Elsevier Science, 629 p., ISBN-13 9780080919980

NCEDC, 2023, Northern California earthquake data center: available via http://quake.geo.berkeley.edu/ncedc/catalog-search.html.

OpenTopography.org -- 2014 USFS Tahoe National Forest Lidar CA1-Guo

Reasenberg, P.A., and Oppenheimer, D., 1985, FPFIT, FPPLOT, and FPPAGE: Fortran computer programs for calculating and displaying earthquake fault-plane solutions: U.S. Geological Survey, Open-File Report, no. 85-739.

Reed, T., 2014, Spatial correlation of earthquakes with two known and two suspected seismogenic faults, north Tahoe-Truckee area, California: MS research, Baylor University, accessible via https://baylor-ir.tdl.org/handle/2104/9097.

Scholz, C.H., 2018, The mechanics of earthquakes and faulting [3rd edition]: Cambridge, Cambridge University Press, 512 p., doi:10.1017/9781316681473, ISBN-13 978-1316615232

Strasser, M., 2017, Spatial correlation of selected earthquakes with the Dog Valley fault in northern California using LiDAR and GPS data: MS research, Baylor University, accessible via https://baylor-ir.tdl.org/handle/2104/10134.

USGS, 2023, Quaternary fault and fold database of the United States: available via https://www.usgs.gov/programs/earthquake-hazards/faults and https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=5a6038b3a1684561a9b0aadf88412fcf

Waldhauser, F. and Schaff, D.P., 2008, Large-scale relocation of two decades of northern California seismicity using cross-correlation and double-difference methods: Journal of Geophysical Research, v. 113, B08311, doi: 10.1029/2007JB005479.

Waldhauser, F., 2001, hypoDD -- A program to compute double-difference hypocenter locations: U.S. Geological Survey, Open-File Report 01-113, 25 p. , accessible via https://www.usgs.gov/publications/hypodd-a-program-compute-double-difference-hypocenter-locations

Waldhauser, F., 2009, Near-real-time double-difference event location using long-term seismic archives, with application to northern California: Bulletin of the Seismic Society of America, v. 99, no. 5, pp. 2736-2748, doi: 10.1785/0120080294.

Waldhauser, F., 2017, Real-time double-difference earthquake locations for northern California, available via http://ddrt.ldeo.columbia.edu/DDRT/index.html.

If you have any questions or comments about this site or its contents, drop an email to Vince Cronin.