Compressive strength, seismic Q, and elastic modulus.

The compressive strength and seismic Q are both seen to be affected by water vapour in a similar way, suggesting a relationship between these mechanical properties. Since volatiles are known to affect the surface energy in different ways, Q and velocity were measured for a variety of volatiles and were found to be reduced by benzene, hexane, ethyl alcohol, methyl alcohol, and water with increasing severity and in qualitative agreement with the reduction in surface energy. The result suggested that volatile-assisted crack growth is the mechanism by which both the strength and the seismic dissipation are affected. -P.Br.