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GEM Global Active Faults Database (GEM GAF-DB)


The GEM Foundation's 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.


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.

Strings 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
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


Contributions to the GEM GAF-DB are highly encouraged. Please see the page on [contributing] for more details.


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 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 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

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 s11069-015-1831-6.

Danciu L, S ̧es ̧etyan 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

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

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 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

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 geophysics/item/1376.

Styron R and Poggi V (2018) GEM North Africa Active Fault Database. DOI:10.13117/N-AFRICA-ACTIVE-FAULTS. URL

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

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 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 i1052-5173-22-10-4.htm.

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 015- 9795- 1.


A global homogenised database of active faults maintained by the GEM Foundation




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