Since 1980, we have detected impulsive noise bursts of seismogenic emissions at 82 kHz, 1525 and 36 Hz with a multipoint detection network around Tokyo region. This system has recorded EM signals prior to several earthquake events and two volcanic eruptions at Mt. Mihara, 1986 and at Mt. Unzen, 1991. By our statistical analysis of these emission characteristics using the last 29 events over the last decade, impulsive magnetic energy generated with rock crash at focus area is carried along the magnetic flux from focus to epicenter, and this magnetic intensity variation seems to be induced the electromagnetic waves at the ground surface. The results of our underground measurement in the tunnel support above explanation.