Investigating non-uniform scaling behavior in Ultra Low Frequency (ULF) earthquake-related geomagnetic signals

The scaling properties of the time dynamics of 2000–2001 ULF geomagnetic data (in the frequency range between 1 mHz and 10 Hz) observed at Izu Peninsula in Japan were investigated. On the basis of detrended fluctuation analysis (DFA), which is a powerful method to detect scaling in non-stationary time series, deviations from uniform power-law scaling were identified and quantified. Our results suggest that a significant non-uniform scaling behavior in ULF geomagnetic data could be related to the occurrence of intense seismic clusters. These first results could be useful in the framework of short-term earthquake prediction.