The precursory electric signals, observed before the Izmit Turkey EQ (Mw = 7.6, August 17th, 1999), analyzed in terms of a hypothetically pre-activated, in the focal area, large scale piezoelectric mechanism

Abstract

The generated, prior to the Izmit Turkey large EQ, preseismic electric signals were recorded in Greece by the VOL Earth's electric field monitoring site. In order to explain their peculiar character and their generating mechanism, a large scale piezoelectric mechanism was assumed that was initiated in the Izmit seismogenic region long before the EQ occurrence time. The theoretical analysis of the adopted physical model justifies the generation of a number of specific electric signals that can be emitted from the focal area before the rock formation failure. The processing of the registered by the VOL monitoring site raw data revealed the presence of similar signals as the expected theoretical ones. Therefore, it is concluded that long before the Izmit EQ occurrence a large scale piezoelectric mechanism was initiated that was modulated too by the tidally triggered lithospheric oscillation and therefore generated the observed preseismic electric signals. The adopted piezoelectric model provides critical information about the time of occurrence of the seismogenic area rock formation failure and therefore the possibility for a real short-term time prediction of a large EQ. The other two predictive EQ parameters, location and magnitude, are discussed in the frame of electric field triangulation and the Lithospheric Seismic Energy Flow Model (LSEFM).