Static and dynamic moduli of the seismogenic layer in Italy

Static and dynamic elastic moduli of Calcare Massiccio (mudstone-limestone) have been measured as a function of frequency over nine decades, using three different standard methods: uniaxial 'static' compression, dual cantilever forced oscillations, and measurement of ultrasonic velocities. An accurate critical comparison using the same techniques on a poly-methyl-methacrylate (PMMA) material shows that an unresolvable 10 to 20% bias exists in the two 'low' frequency standard techniques, whereas the ultrasonic measurements are more accurate and reproducible within 5%. No significant frequency dependence is found for Calcare Massiccio, which gives a Young's modulus of (75 +/- 7) GPa and a Poisson ratio of (0.28+/-0.02).