Empirical Relation between Modified Mercalli Intensity Scale and PGA, PGV in California

1) For California by Wald, D. J. et al (1999) Intensity I, II-III, IV, V, VI, VII, VIII, IX, X+ PGA(% G) <0.17, 0.17-1.4, 1.4-3.9, 3.9-9.2, 9.2-18, 18-34, 34-65, 65-124, >124 PGV(cm/s)<0.1, 0.1-1.1, 1.1-3.4, 3.4-8.1, 8.1-16, 16-31, 31-60, 60-116, >116 Empirical Formulas: IMM=3.66log(PGA)-1.66 for V<=ImmVIII IMM=3.47log(PGV)+2.35 for V<=IMMIX Ref: Wald, D. J. et al (1999), Earthquake Spectra, Vol. 15, No. 3, 557-564. 2) Trifunac and Brady (1975) Empirical Formulas: log(PGA)=0.30IMM-0.18 log(PGV)=0.30IMM+0.014 for IVIMMX, where PGA in cm/sec2, PGV in cm/sec Ref: Trifunac, M. D. and A. G. Brady (1975), Bull. Seism. Soc. Am., Vol. 65, p1243-1253.�v