The IASPEI Reference Event (GT) List (1959-2017) Maintained by the ISC
Date: 4/24/2019
Time: 09:30 AM
Room: Cascade I
As part of its mission, the International Seismological Centre (ISC) maintains the IASPEI Reference Event List (Ground Truth, GT). This is a database of earthquakes and explosions, for which epicentres are known with high confidence, with an error typically up to 10 km that is defined by the 95% confidence level. Specifically, the events are defined as GTX, where the source is known within X km, to a 95% confidence level.
The GT database currently contains ~9,500 events that occurred between 1959 and 2017. These events are large enough to be recorded at teleseismic distances but small enough to be considered as point source (mb/MS < 6.0). The GT events are associated with over 1 million seismic phases recorded from local/regional to teleseismic distances, and therefore, is an ideal dataset for velocity model/location calibration purposes. In particular, the new ISC location method (Bondar & Storchak, 2011) has been extensively tested using GT events and shown acceptable fit before it was put in operation at the ISC.
The database is maintained by the ISC under the supervision of the IASPEI working group on Improved Locations. The ISC routinely searches for candidate events in line with (Bondár et al, 2008) or (Bondár & McLaughlin, 2009), relocates and validates them accordingly, based on selection criteria with respect to phase arrivals in local distances, azimuthal gap and secondary azimuthal gap metrics.
Useful GT events are also proposed as a result of RSTT (regional seismic travel times) workshops held by the CTBTO where participants from seismological networks in a specific region bring together the results of their analysis of waveforms that are often not openly available.
Typically, events with a 95% confidence level within the 0-5 km range are nuclear and chemical explosions, rock bursts, mine-induced events, as well as a few earthquakes, whereas GT5 events are typically earthquakes with crustal depths.
We encourage the use of this dataset for testing and validation of new location algorithms, velocity models and corresponding location uncertainties.
Presenting Author: Dmitry A. Storchak
Authors
Konstantinos Lentas kostas@isc.ac.uk International Seismological Centre, Thatcham, , United Kingdom |
Dmitry A Storchak dmitry@isc.ac.uk International Seismological Centre, Thatcham, , United Kingdom Presenting Author
Corresponding Author
|
Domenico Di Giacomo domenico@isc.ac.uk International Seismological Centre, Thatcham, , United Kingdom |
James Harris james@isc.ac.uk International Seismological Centre, Thatcham, , United Kingdom |
The IASPEI Reference Event (GT) List (1959-2017) Maintained by the ISC
Category
From Drifting to Anchored: Advances in Improving Absolute Hypocenter Location Accuracy for Natural, Induced and Explosion Seismic Events