Study on Earth Crust Anomaly Through Sound Signal Processing of ELF Band Electromagnetic-Wave Precursor

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1. Anomalous electromagnetic-wave radiation has been detected in advance earthquakes and volcanic eruption by the developed high sensitive receiver of order of sub-pT per root Hertz at the ELF band of 17Hz and 223Hz2. The radiation was classified into several categories or patterns according to their way of radiation.(1)The pattern at the occasion of volcanic swarm experienced at Itoh-city, Central Japan, was appearing with severe variation in the amplitude like a discharge. The radiation mechanism is conceived due to discharge from the earth surface to the air due to electron charges by oxidization of degas which is originated from the deep melted rock or magma. The same radiation was appeared at the Miyake island's volcanic eruption on August18th of 2000.(2) The spectacular radiation was obtained when the diastrophism of islands in the course of the same Miyake volcanic eruption, the distance between Niijima and Kouzu islands separated 10cm a day, the phenomenon was also observed by GPS and seismometer simultaneously. The radiation is thought due to current compensating the change in electrical property as conductivity and dielectric constant of the earth crust distorted by mechanical pressure.(3) The smoothed increase in the radiation level was observed at the chain of earthquakes in the central Shizuoka in April to September 2001. The area was continuously subjected to the plate slip between sea and land plates in recent years. The observed anomalies were estimated from the way of radiation behavior as the possible thermal agitation noise of free electrons excited by the friction heat energy between the plates.3. Sound signal processing methods and electromagnetic-wave analysis were successfully applied to the obtained data in order to extract the spectacular precursor components and/or to eliminate the received noises.