HR: 11:50h
AN: S52B-07    [Abstracts]
TI: Near Real Time Seismic Discrimination at Regional Distances Using a Voting Scheme of Discriminators Over the Lg Phase
AU: * Rueda, J J
EM: jjrueda@fomento.es
AF: Instituto Geografico Nacional, General Ibanez de Ibero 3, Madrid, 28003, Spain
AU: Mezcua, J A
EM: jmezcua@fomento.es
AF: Instituto Geografico Nacional, General Ibanez de Ibero 3, Madrid, 28003, Spain
AU: Mezcua, J A
EM: jmezcua@fomento.es
AF: Universidad Politecnica de Madrid, Campus Sur, Aut. Valencia 7.5, Madrid, 28031, Spain
AB: The recent installation of telemetered BB stations as part of the National Seismic Network in Spain makes necessary to discriminate in the low magnitude range (around ML=2) between earthquakes and chemical explosions. The process should be in real time because an automated seismic bulletin is sent to different agencies. The discrimination processes uses a voting scheme based on the experience gained with a training set of 200 events which by a independent way is known its natural or artificial condition. The discriminators were applied to the Lg phase which is well developed at regional distances and were: spectral variance, spectral slope, relation variance-slope, and the logarithm of the ratio of amplitudes in the frequency bands, 1-2 hz/6-8 hz and 1-2 hz/7-9 hz respectively. The weights assigned to each discriminator are based in percentage of skill as compared with true classification. The most powerful index is the amplitude ratio 1-2 hz/ 7-9 hz and the lowest is the variance of the Lg phase. As new set of data is entered the system is trained as soon as the true classification is confirmed.
DE: 7219 Seismic monitoring and test-ban treaty verification
SC: Seismology [S]
MN: 2007 Fall Meeting