Reproducible and predictable electrical pulses with peak powers of a few hundred kilowatts lasting for a few microseconds can be obtained from shock−wave compressed ferroelectrics. In this work, impact−loading techniques are used to investigate the electromechanical response of poled specimens of a ferroelectric ceramic, PZT 95/5, to long−duration shock pulses. The experiments are conducted in the normal mode in which the shock propagation vector is perpendicular to the remanent polarization. Current histories are obtained as a function of load resistance for a fixed shock amplitude of 1.4 GPa, and few additional experiments investigate the stress dependence of the electrical response. A simple, though specific, model is developed that gives good agreement with observed results. The extension of this model to other materials and shock−loading conditions is discussed.

Shock-compression experiments were performed on specimens of nitromethane for several values of initial temperature. From these data, a continuum of Hugoniots centered at any initial temperature between the atmospheric pressure freezing and boiling states was obtained. The energy-pressure-volume equation of state then followed from a combination of the known variation of energy with temperature along the atmospheric pressure isobar and the Hugoniot jump relations. The energy-entropy-volume equation was generated by a numerical integration of the coupled differential equations governing the entropy and temperature variation along a Hugoniot. This work is believed to constitute the first totally experimental determination of the equation of state of a liquid in the 100 kbar region.

During the 1984 field season, two research holes were cored into the Inyo chain of young rhyolite domes, which cuts across the northwest margin of Long Valley Caldera, Calif. (Figure 1). One hole slanted under the vent of Obsidian Dome and completely penetrated the conduit of the volcano. It was spudded on August 16 and reached its final depth on September 9. The second hole was sited along Glass Creek between Obsidian Dome and the next dome to the south; it intersected the rhyolite dike which underlies the chain. It was spudded on September 18 and reached final depth on October 28.

In experiments on the electrical properties of rocks at high frequencies, the measured current has contributions from both conduction and displacement currents, and these are related to the bulk conductivity and dielectric permittivity, respectively. In the present model, the bulk electrical conductivity of a specimen is taken to be a constant given by Archie’s rule, whereas its frequency‐dependent permittivity is taken to be a generalization of Sillars’ model of a composite dielectric. The generalized Sillars’ model treats the pores as being an assemblage of spheroidally shaped inclusions with different orientations and aspect ratios. The conductivity of these spheroids, that is, the conductivity of the pore fluid, influences the frequency dependence of the permittivity in a manner that is in reasonable accord with available data. Furthermore, when applied to the dielectric data obtained in experiments on saturated rocks, the model yields distributions of pore shapes. These distributions are used to estimate the electrical response of oil‐ and water‐wet rocks that are unsaturated.

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