Analyzing Scaling Behavioral Trends in Self-potential Earthquake-related Data Measured in Mexico

The scaling behaviour of self-potential data (in the frequency range between 0 and 0.125Hz) observed in 1995 at Acapulco station in Mexico were investigated using the detrended fluctuation analysis (DFA), which is a powerful method to detect scaling in nonstationary time series. Approximately two scaling regions with two different scaling exponents α1 (on low timescales) and α2 (on high timescales)can be detected in the data, with a timevaring crossover. The analysis of the time variation of the scaling exponents in the two scaling regions shows, particularly, a significant increase of α1 before the occurrence of the strongest earthquake of magnitude M=7.4, that struck the area on September 14, 1995. These first results could be useful in the framework of earthquake prediction studies.