How is it of relevance?
The knowledge of fault positions and current activity is of vital knowledge for the calculation of seismic hazard. The current state of the art only consists of a number of national and regional databases that are compiled according to different criteria and parameters. The first version of this database therefore is a unified database that is capable of incorporating information from different sources and formats. It is accompanied by a tool for capture of new data, so that the database can continue to compile faults from around the globe.
Who is developing the database?
Kelvin Berryman, Annemarie Christophersen and Nicola Litchfield with their colleagues from GNS Science are the driving force behind this project. Kerry Sieh from EOS Singapore and Ross Stein from the USGS have played an important role, as have renowned geologists from around the globe, including Carlos Costa, Roberto Basili, Kathy Haller, Richard Koehler, Toshikazu Yoshioka, Dan Clark, Ned Field, Gavin Hayes, Margaret Boetcher, and Bob Yeats. Regional collaboration is key to the project and fellow-geologists from areas currently scarsely covered by faults databases in Asia, Latin America and Africa have been of great importance to organize workshops such as in Thailand (November 2012).
GEM’s Model Facility has been developing the fault data capture tool, in collaboration with the geologists from GNS.
In a nutshell
The database contains active faults and fault sources. More precisely it contains observations of faults that have slipped in the current tectonic regime, as well as inferred seismic sources.
In addition to continental faults, also subduction zone slabs, oceanic transform faults and mid-ocean ridges are included, which ensure that the greatest percentage of global earthquakes larger than magnitude 6.5 can be associated with faults in the database. This will support future testing of fault-based activity models against those based on smoothed seismicity.
The fault capture tool is an intuitive tool that allows geologists to capture all data relevant for insertion of new faults, see it in a GIS-environment and allows the user to subsequently use and combine the uploaded data with other GEM data in the OpenQuake Platform.
A database structure is currently in place that allows importing (rich) existing databases (such as the active fault datasets from the United States and New Zealand). New discoveries and data can be uploaded to the database after review, by using the active fault data capture tool.
Contents Version 1
The first version of the database (2014) will contain the following datasets:
- New Zealand: active fault and active fault source data
- Japan: active fault database
- Alaska: active fault and fold database
- Europe: through collaboration with the SHARE project
- South Asia: frontal fault system Himalayas
- South-East Asia & Pacific: what data is still under discussion with collaborators in the region, such as in Indonesia and Thailand
- South America: what data is still under discussion
In addition to national / regional data, there will also be..
- Global Subduction Zone Database
- Oceanic Transforms
Likely are also datasets from the USA (faults and folds) and Australia.
The Fault Capture Tool
The fault capture tool is a comprehensive tool that allows geologists to add new discoveries in an interactive way to the OpenQuake platform, allowing drawing the fault directly in the tool, as well as by adding detailed information on the fault. All data can subsequently be saved and used by the geologist and can be submitted for review, so that after validation it can be included in the database.
Several workshops have been organised so far, one is planned for Mexico from 9-12 April 2013 and others are possible, given regional interest.
19-21 November 2012: Asia-Pacific Regional Fault Workshop
The GEM Active Faults team, Regional Integrated Multi-Hazard Early Warning System (RIMES), and Asian Institute of Technology (AIT) organised a 3-day regional workshop for fault experts in South-East/Asia and the Pacific, which was led by Teraphan Ornthammarath from RIMES, Pilar Villamor from GNS Science and Nick Horspool from Geoscience Australia.
In total 26 geologists and other experts from 9 countries throughout the region participated in the workshop; the participants represented knowledge from Thailand, Indonesia, Philippines, Myanmar, Singapore, Vietnam, Papua New Guinea, Australia and New Zealand.
The workshop discussed the database, developments in the region on faults and fault discovery, the data included so far for the region. Collaboration on faults worldwide and in the area was discussed during the workshop. The fault data capture tool was demonstrated and explained, to allow participants to see how they can use it in their future work, and for them to provide feedback for further improvement of the tool.
18-21 September 2011: Subduction Zones Workshop
18 participants from eight countries worked intensively for four days at the USGS in Menlo Park, co-hosted by Kelvin Berryman and Ross Stein (GEM Scientific Board), and organized by Nicola Litchfield and Laura Wallace. An evening paella cooking class ice-breaker and a USGS BBQ closer also gave the participants a chance to catch our breath and enjoy each other during the meeting.
In the wake of the past decade's great megathrust events in Sumatra, Chile, and Japan, GEM Faulted Earth sought to capture the geometry and seismic properties of all 40,000 km of subduction zones for its active fault inventory. Neither the Andaman nor the Japan trench were thought to be capable of producing a shock similar to M9, and so the group wanted to take a fresh and synpotic view of megathrust behavior, strongly influenced by the work of Peter Bird, Gavin Hayes, Kelan Wang, Thorne Lay, and Rob McCaffrey and Yan Kagan (through their papers).
Some subduction zones, such as the Marianas, are widely thought to be seismically incapable of M>=8 shocks, but this view is now being justifiably questioned, and instead the earthquake record may simply be too short. GEM Faulted Earth will use Gavin Hayes' SLAB 1.0 for the subduction geometry and rake, but will take a logic-tree approach to populating the megathrusts with earthquakes. Some weight will be given to a M>=9 shock on all subduction zones (with the magnitude limited only by the total length and width of contiguous zones), but also some to alternatives that use the seismic coupling and 'soft' segment boundaries (boundaries to most but not all shocks) where such data is available. Marco Pagani, GEM’s Hazard Coordinator, guided us on how the OpenQuake software will digest our data, and also reflected on how best to modify or augment OpenQuake to best reflect the diversity and uncertainty of our knowledge, and its enormous impact on hazard.
How can I use the database and the tool?
The database is currently being tested against a number of the most advanced national inventories of faults from around the globe. The tool for new data compilation is also being tested and evaluated by regional communities so as to make it as much as possible tailored to the needs of geologists worldwide.
Both the database and the tool will be available in the OpenQuake Platform and can be used interactively from 2014. There will also be a guideline available for geologists for using the tool. A data dictionary will furthermore facilitate use of both database and tool.
You can already download and comment on the document that reports on existing fault databases worldwide, their possibilities and limitations that we posted in GEM Nexus:
How can I contribute?
- We are keen to hear from geologists worldwide to see how we can collaborate on the database
- We are always interested in receiving feedback from organisations and individuals that are working on active faults
- If you have other ideas or questions, feel free to get in touch as well
Contact us through Annemarie Christophersen: A.Christophersen@gns.cri.nz