The underground fluid short-term anomalies of earthquake activity are studied. Two kinds of typical characteristies of precursors, the turn-around type and the
The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, 'fast-waves' and '
The authors proposed a method for obtaining high-quality acceleration seismograms from velocity type seismograms of digital Seismographic network, and took as a