Compressional and Shear Wave Velocities of Volcanic Rocks and Glasses to 900°C at 20 Kbar
The elastic properties of igneous rocks at high temperature must be measured under high pressure, because the pores and cracks in rock samples enormously influence their elasticity. No reliable data have been reported covering the elasticity of rocks above 500°C at high pressure. The present study reports on variations of the compressional and shear wave velocities, VP and VS, of igneous rocks, including a natural glass and a commercial glass up to 900°C or more and to 20 kbar. The present report deals mainly with the acidic rock series; the results on the basic rock series will not be presented here, because the data for them are incomplete. From a rheological viewpoint, igneous rocks are classified into three groups, (1) pure glasses, (2) mixtures of glass and crystalline grains, and (3) perfect crystalline aggregate. The first two groups may be similar to volcanic rock and the last one to plutonic rock. Glassy substances in rock samples are expected to have large effects on their elastic properties.
KeywordsVolcanic Rock Igneous Rock Shear Wave Velocity Crystalline Rock Pyrex Glass
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