QUANTITATIVE MEASURE OF THE GOODNESS-OF-FIT OFSYNTHETIC SEISMOGRAMS

摘要

To develop credibility of synthetic seismograms for engineering applications, there is aneed for a quantitative score that can be used to characterize the how well the syntheticmatches the statistical characteristics of observed records. Recognizing that strongmotion is a very complex time series and any measure that relies on a single parameterfor the comparison is seriously incomplete, this paper examines use of a suite ofmeasurements. To be specific, we score seismograms that have been filtered into up toten narrow pass-bands. Each frequency band is scored on ten different characteristics.The characteristics scored are the peak acceleration, peak velocity, peak displacement,Arias intensity, the integral of velocity squared, Fourier spectrum and accelerationresponse spectrum on a frequency-by-frequency basis, the shape of the normalizedintegrals of acceleration and velocity squared, and the cross correlation. Eachcharacteristic is compared on a scale from 0 to 10, with 10 giving perfect agreement.Scores for each parameter are averaged to yield an overall quality of fit. A score below 4is a poor fit, a score of 4-6 is a fair fit, a score of 6 to 8 is a good fit, and a score over 8 isan excellent fit. One horizontal component of an actual seismogram typically fits theother horizontal component in the 'good' range. The method is applied to a blindprediction of ground motions at a station 3 km from the fault in the M7.9 Denali Fault,Alaska, earthquake of November 3, 2002.