Sudden drop of fractal dimension of electromagnetic emissions recorded prior to significant earthquake

摘要

The variation of fractal dimension and entropy during a damage evolutionprocess, especially approaching critical failure, has been recentlyinvestigated. A sudden drop of fractal dimension has been proposed as aquantitative indicator of damage localization or a likely precursor of animpending catastrophic failure. In this contribution, electromagnetic emissionsrecorded prior to significant earthquake are analysed to investigate whetherthey also present such sudden fractal dimension and entropy drops as the maincatastrophic event is approaching. The pre-earthquake electromagnetic timeseries analysis results reveal a good agreement to the theoretically expectedones indicating that the critical fracture is approaching.