The Multifractal Detrended Fluctuation Analysis (Mf-Dfa) and Anomalies in Geomagnetic Total Field Intensity Prior To Mw~5.5 Earthquake

Abstract

In the research article, we report the anomalies observed in geomagnetic total field intensity (B Total ) prior to Mw 5.5 Kokrajhar event. The multifractal analysis was scrutinized to reveal the underlying dynamics in the Geomagnetic Total field intensity time series. The multifractal spectrum on the day when the event occurred (T Event day ) and its surrogate (T Surrogate ) was investigated to understand the behavior and dynamics hidden in B Total time series. A significant variation in the multifractal spectrum was observed between T Day one (multifractal spectrum a day prior to the event) and T Event day . It was also observed that the mulfractality of B Total when the event occurred (T Event day ) got stronger than the multifractality of T Day one and was sourced from low values distribution. The multifractality in T Day one and T Event day time series was not from source type long range correlation or sourced from broad probability density function. The investigation also manifests some nonlinear features which probably evinces the anomalies to be seismic induced. The observations are elaborately emphasized in the article. The study scrutinizes the underlying dynamics in geomagnetic field intensity time series for earthquake precursory and forecast studies.