Showing papers by "David M. Boore published in 1993"

Methods for regression analysis of strong-motion data

Abstract: We introduce a new computational method for implementing Brillinger and Preisler's (1984, 1985) one-stage maximum-likelihood analysis of strong-motion data. We also reexamine two-stage methods and agree with Masuda and Ohtake (1992) that rigorous analysis requires off-diagonal terms in the weighting matrix for the second-stage regression but note that Masuda and Ohtake failed to account for the earthquake-to-earthquake component of variance. Analysis by Monte Carlo methods shows that both one-stage and two-stage methods, properly applied, are unbiased and that they have comparable uncertainties. Both give the same correct results when applied to the data that Fukushima and Tanaka (1990) have shown cannot be satisfactorily analyzed by ordinary least squares. The two-stage method is more efficient computationally, but for typical problems neither method requires enough time to make efficiency important. Of the two methods, only the two-stage method can readily be used with the techniques described by Toro (1981) and McLaughlin (1991) for overcoming the bias due to instruments that do not trigger.

Empirical prediction of strong ground motion

Abstract: In 1982, we published equations for the prediction of various measures of ground motion as a function of earthquake magnitude, distance from the earthquake rupture, and site geology. Many more strong-motion recordings have been obtained since we published our equations. The predictions of the ground motions from our published equations are in reasonable agreement with the peak accelerations from the new data. The increased number of data, however, allow us to refine our predictions for some regions of magnitude and distance space, and perhaps for other variables.