Estimativa dos Limites de Detectabilidade de Estações Sismográficas no Brasil

Abstract

The detectability threshold  μ50. and  μ90 for P and PKP waves in the distance ranges 300-900 and 1200-1700 respectively, were determined for the main seismographic stations in Brazil by analyzing records of one year at each station. It is shown that the "Incremental Detection Probability" (i.e., the probability of one event being detected given its magnitude) as a function of the USGS mb magnitude is well fit by a Gaussian cumulative distribution function. The detectability curves were fit by the maximum likelihood method associated with a probit transformation. For the P wave, differences in  μ50. (the magnitude with a detection probability of 50%) of up to 1.2 magnitude units were found among the stations. The best detectability was found for the station ITR (μ50 = 4.73).