Generation Mechanism of Electric Impulses Observed in Explosion Seismic Experiments

抄録

Generation mechanisms of the electric impulses in the underground chemical explosions are described in this paper. The electric impulses just after triggering were commonly observed in three explosion seismic experiments. The common characteristics of the impulses are as follows: 1) The duration time of the impulse train is always less than 10 ms and no impulse is detected after 10 ms. 2) The duration time of each impulse is approximately 1 ms, the time structure is quite different, and the occurrence is intermittent. 3) The electric charge generation process can be modeled by a vertical electric dipole. It is the first time to clearly show that the duration of the impulses is caused by the total length of the dynamite explosion. The characteristics can be explained by two closely coupled generation processes; chemical explosion and excitation of electric charges by a thermo- or mechano-electric process. The primary process is explained by means of the excitation of high-temperature and high-pressure with a dynamite explosion. The secondary process is interpreted as a theme- or mechano-electric conversion process excited either by thermal energy or by mechanical energy in surrounding media consisted of rock and water. Two thermo-electric and four mechano-electric conversion processes are discussed in terms of the time structure, the direction of expected electric dipoles, and the confinement in the vicinity of dynamite. It is concluded that the most probable source of the observed electric impulses is the fractoelectric effect.