# GEM Global Active Faults Database (GEM GAF-DB) [![DOI](https://zenodo.org/badge/91775241.svg)](https://zenodo.org/badge/latestdoi/91775241) The [GEM Foundation's][gem] Global Active Faults is building a comprehensive, global dataset of active fault traces of seismogenic concern. The GEM GAF-DB comprises GIS files hosted here of fault traces and small amount of relevant attributes or metadata (fault geometry, kinematics, slip rate, etc.) useful for seismic hazard modeling and other tectonic applications. The dataset is being assembled primarily as a part of GEM's global Probabilistic Seismic Hazard Modeling efforts, although we hope that the data find wide use in research, education and general interest among many users. The dataset is freely and publicly available here, under a Creative Commons attribution sharealike license. The dataset currently covers most of the deforming continental regions on earth with the exceptions of the Malay Archipelago, Madagascar, Canada, and a few other regions. The data is viewable in an interactive map [here][gaf-viewer]. ## Citation The GEM GAF-DB has been published in *Earthquake Spectra*. The citation is: Styron, Richard, and Marco Pagani. “The GEM Global Active Faults Database.” *Earthquake Spectra*, vol. 36, no. 1_suppl, Oct. 2020, pp. 160–180, doi:10.1177/8755293020944182. The link to the publication is here: ## Data Format ### Data Table Attribute | Data Type | Description | Example ---------------------|-----------|------------------------------|------------ dip | tuple | Dip | (40,30,50) dip_dir | string | Dip direction | W downthrown_side_id | string | direction of downthrown side | NE average_rake | tuple | Slip rake of fault | (45,25,55) slip_type | string | Kinematic type | Sinistral strike_slip_rate | tuple | Strike slip rate on fault |(1.5,0.5,2.5) dip_slip_rate | tuple | Dip slip rate |(1.5,0.5,2.5) vert_slip_rate | tuple | Vertial slip rate |(1.5,0.5,2.5) shortening_rate | tuple | Horizontal shortening rate |(1.5,0.5,2.5) accuracy | integer | Denominator of map scale | 40000 activity_confidence | integer | Certainty of neotectonic activity | 1 exposure_quality | integer | How well exposed (visible) fault is | 2 epistemic_quality | integer | Certainty that fault exists here | 1 last_movement | string | Date of last earthquake | 1865 name | string | Name of fault zone | Polochic fz_name | string | Name of fault zone | Motagua-Polochic reference | string | Paper used | Rogers and Mann, 2007 notes | string | Any relevant info | May be creeping ogc_fid | integer | ID used by GIS | 8 catalog_id | string | Global ID | CCARA_8 ### Data Types There are three main data types used in the GAF attribute table, `tuple`, `integer` and `string`. A `tuple` is a 3-[tuple] of real (floating-point or integer) numbers representing continuous random variables such as slip rate. The tuple has the format `(most-likely, min, max)`. In some instances where there is no estimated uncertainty in the parameter of interest, the tuple may be simply given as `(most-likely,,)`; this is most common for the dip of purely strike-slip faults. In typed databases it is actually represented by a string, so the parentheses and commas will be preserved. `Rake` is in Aki-Richards convention. All slip rate fields except `shortening_rate` describe the slip rate or component on the actual fault, and are in magnitudes, i.e. are always positive. `shortening_rate` describes the horizontal contraction rate (heave) of a fault (such as a GPS measurement); this is not the dip slip rate. Extension across a fault is negative. An `Integer` is used as a categorical variable in this database, typically to denote the relative epistemic uncertainty in a parameter. `1` is most certain, `2` is moderately uncertain, and `3` is highly uncertain. The other uses of `Integer` types are for table indices in many constituent datasets, and in the `accuracy` attribute which denotes the denominator of the map scale during fault mapping and digitization; for example, a fault that was mapped in GIS at a 1/40,000 (or 1:40,000) scale will have an accuracy of `40000`. `String`s for fields with words. # Constituent Datasets The GEM GAF-DB is compiled from a variety of regional to global active fault datasets. These are given here: Coverage Region |Reference |Peer-Review|Dataset Name (if any) ------------------------------|--------------------------|-----------|----------------------------- New Zealand |Litchfield et al., 2014 |Yes |*none* Australia |Allen et al., 2018 |Yes |*none* East Africa |Macgregor, 2014 |Yes |*none* Middle East |Danciu et al., 2018 |Yes |EMME South America |Alvarado et al., 2017 |No |SARA Europe |Woessner et al., 2015 |Yes |SHARE Northern Andes |Veloza et al., 2012 |Yes |Active Tectonics of the Andes Indo-Asian Collision Zone |Styron et al., 2010 |Yes |HimaTibetMap Philippines |Penarubia et al., 2019 |Yes |*none* US mainland |Petersen et al., 2014 |Yes |HazFaults California |Dawson and Weldon, 2013 |Yes |UCERF3 Taiwan |Shyu et al., 2016 |Yes |*none* Mexico |Villegas et al., 2017 |Yes |*none* Southeast Asia |Chan et al., 2017 |No |*none* Northeast Asia |Styron et al., 2018 |No |*none* North Africa |Styron and Poggi, 2018 |Yes |*none* Southern Malawi |Williams et al., 2021 |Yes |SMSSD Central America and Caribbean |Styron et al., 2020 |Yes |CCAF Global (various regions) |Christophersen et al. 2015|Yes |Faulted Earth Global (plate boundaries) |Bird, 3002 |Yes |PB2002 Full reference information is given below. Please note that these are subject to regular change. # File Formats The database is currently available in 4 formats, [GeoJSON], [GeoPackage], KML, and [ESRI ShapeFile]. Which file format is most appropriate depends on the software package that is being used. QGIS users and anyone making webmaps or an API will find the GeoJSON format most useful. This is also the version of record as it is tracked best with version control. However, ESRI does not seem to provide acceptable GeoJSON support; ArcGIS users should be able to use the GeoPackage format (note that we have no access to ArcGIS and are unable to test these files for compatibility). ESRI's legacy ShapeFile format is also provided but this is not a good choice as that format truncates both column names and longer text fields such as `Notes`. **If you are downloading individual files instead of cloning the repository:** Please note that GitHub may display a version of the data that is formatted for viewing within its built-in webmap, and not display the actual data. If you press the 'Download' button, however, you may download the real file. Additional file formats will be provided once the Version 1 of the database is complete; if you have specific needs, please contact richard dot styron at globalquakemodel.org. # Contributing Contributions to the GEM GAF-DB are highly encouraged. Please see the page on [contributing] for more details. [contribuing]: ./contributing.md # References Allen TI, Griffin J, Ghasemi H, Leonard M, Clark D and Geoscience Australia (2018) The 2018 National Seismic Hazard Assessment for Australia: model overview. ISBN 978-1-925848-00-7. URL https://doi.org/10.11636/Record.2018.027. OCLC: 1089757486. Alvarado A, Audemard F, Benavente Escobar C, Santibanez Boric I, Cembrano Perasso J, Costa C, Delgado Madera GF, García-Pelaez JA, Masquelin E, Minaya E, López MC, Paolini M, Perez I, Grupo de Neotectónica de SEGEMAR and Styron R (2017) the South American Risk Assessment Active Fault Database. DOI:10.13117/SARA-ACTIVE-FAULTS. URL https://github.com/GEMScienceTools/SARA-Active-Faults. Bird P (2003) An updated digital model of plate boundaries. Geochemistry, Geophysics, Geosystems 4(3): 1027. DOI:10.1029/2001GC000252. URL http://onlinelibrary.wiley.com/doi/10.1029/2001GC000252/abstract. Chan CH, Wang Y, Shi X, Ornthammarath T, Warnitchai P, Kosuwan S, Thant M, Nguyen PH, Nguyen LM, Solidum Jr R and others (2017) Toward uniform probabilistic seismic hazard assessments for Southeast Asia. In: AGU Fall Meeting Abstracts. Christophersen A, Litchfield N, Berryman K, Thomas R, Basili R, Wallace L, Ries W, Hayes GP, Haller KM, Yoshioka T, Koehler RD, Clark D, Wolfson-Schwehr M, Boettcher MS, Villamor P, Horspool N, Ornthammarath T, Zuñiga R, Langridge RM, Stirling MW, Goded T, Costa C and Yeats R (2015b) Development of the Global Earthquake Model’s neotectonic fault database. Natural Hazards 79(1): 111–135. DOI:10.1007/s11069-015-1831-6. URL https://link.springer.com/article/10.1007/s11069-015-1831-6. Danciu L, Şeşetyan K, Demircioglu M, Gülen L, Zare M, Basili R, Elias A, Adamia S, Tsereteli N, Yalçın H, Utkucu M, Khan MA, Sayab M, Hessami K, Rovida AN, Stucchi M, Burg JP, Karakhanian A, Babayan H, Avanesyan M, Mammadli T, Al-Qaryouti M, Kalafat D, Varazanashvili O, Erdik M and Giardini D (2018) The 2014 Earthquake Model of the Middle East: seismogenic sources. Bulletin of Earthquake Engineering 16(8): 3465–3496. DOI:10.1007/s10518-017-0096-8. URL https://doi.org/10.1007/s10518-017-0096-8 Dawson T and Weldon R (2013) Geologic-Slip-Rate Data and Geologic Deformation Model. In: Uniform California earthquake rupture forecast, version 3 (UCERF3), number 228 in California Geological Survey Special Report. Litchfield NJ, Dissen RV, Sutherland R, Barnes PM, Cox SC, Norris R, Beavan RJ, Langridge R, Villamor P, Berryman K, Stirling M, Nicol A, Nodder S, Lamarche G, Barrell DJA, Pettinga JR, Little T, Pondard N, Mountjoy JJ and Clark K (2014) A model of active faulting in New Zealand. New Zealand Journal of Geology and Geophysics 57(1): 32–56. DOI:10.1080/00288306.2013.854256. URL https://doi.org/10.1080/00288306.2013.854256. Macgregor D (2015) History of the development of the East African Rift System: A series of interpreted maps through time. Journal of African Earth Sciences 101: 232–252. DOI:10.1016/j.jafrearsci.2014.09.016. URL http://www.sciencedirect.com/science/article/pii/S1464343X14003240. Peñarubia C, Kendra Johnson, Styron RH, Sevilla WIG, Perez JS, Bonita JD, Narag IC, Solidum Jr RU, Pagani MM, Allen TI and Allen TI (2019) Probabilistic Seismic Hazard Analysis model for the Philippines. Earthquake Spectra. In press. Petersen MD, Moschetti MP, Powers PM, Mueller CS, Haller KM, Frankel AD, Zeng Y, Rezaeian S, Harmsen S, Boyd O and others (2014) Documentation for the 2014 update of the United States national seismic hazard maps, Open-File Report 2014-1091. Technical Report 2014-1091, U.S. Geological Survey, Reston, VA. URL https://dx.doi.org/10.3133/ofr20141091. Shyu JBH, Chuang YR, Chen YL, Lee YR and Cheng CT (2016) A New On-Land Seismogenic Structure Source Database from the Taiwan Earthquake Model (TEM) Project for Seismic Hazard Analysis of Taiwan. Terrestrial, Atmospheric and Oceanic Sciences 27(3): 311. DOI:10.3319/TAO.2015.11.27.02(TEM). URL http://tao.cgu.org.tw/index.php/articles/archive/geophysics/item/1376. Styron R and Poggi V (2018) GEM North Africa Active Fault Database. DOI:10.13117/N-AFRICA-ACTIVE-FAULTS. URL https://github.com/GEMScienceTools/n_africa_active_faults. Styron R, Garcia-Pelaez J and Pagani M (????) CCAF-DB: The Caribbean and Central American Active Fault Database. Natural Hazards and Earth System Science, In revision Styron R, Poggi V and Lunina OV (2018) GEM Northeastern Asia Active Fault Database. DOI:10.13117/NE-ASIA-ACTIVE-FAULTS. URL https://github.com/GEMScienceTools/ne-asia-active-faults. Styron R, Taylor M and Okoronkwo K (2010) Database of Active Structures From the Indo-Asian Collision. Eos, Transactions American Geophysical Union 91(20): 181–182. DOI:10.1029/2010EO200001. URL http://onlinelibrary.wiley.com/doi/10.1029/2010EO200001/abstract. Veloza G, Styron R, Taylor M and Mora A (2012) Open-source archive of active faults for northwest South America. GSA Today 22(10): 4–10. DOI:10.1130/GSAT-G156A.1. URL http://www.geosociety.org/gsatoday/archive/22/10/abstract/i1052-5173-22-10-4.htm. Williams, J. N., Mdala, H., Fagereng, Å., Wedmore, L. N. J., Biggs, J., Dulanya, Z., Chindandali, P., and Mphepo, F.: A systems-based approach to parameterise seismic hazard in regions with little historical or instrumental seismicity: active fault and seismogenic source databases for southern Malawi, Solid Earth, 12, 187–217, https://doi.org/10.5194/se-12-187-2021, 2021. Woessner J, Laurentiu D, Giardini D, Crowley H, Cotton F, Grünthal G, Valensise G, Arvidsson R, Basili R, Demircioglu MB, Hiemer S, Meletti C, Musson RW, Rovida AN, Sesetyan K, Stucchi M and The SHARE Consortium (2015) The 2013 European Seismic Hazard Model: key components and results. Bulletin of Earthquake Engineering 13(12): 3553–3596. DOI:10.1007/s10518-015-9795-1. URL https://doi.org/10.1007/s10518-015-9795-1. [gem]: globalquakemodel.org [gaf-viewer]: https://blogs.openquake.org/hazard/global-active-fault-viewer/ [tuple]: https://en.wikipedia.org/wiki/Tuple [GeoJSON]: http://geojson.org/ [GeoPackage]: https://www.geopackage.org/ [ESRI ShapeFile]: https://support.esri.com/en/white-paper/279