Analysis of site effects in magnetotelluric data by using the multifractal detrended fluctuation analysis

We investigated the multifractal structure of magnetic field H measured by magnetotelluric stations installed at three different sites in Taiwan, characterized by different site conditions. Magnetotelluric data include three components of the magnetic field H. We applied the multifractal detrended fluctuation analysis (MF-DFA) to magnetic magnitude time series (evaluated as the L2 norm). Our findings point out to a significant discrimination among these data in terms of multifractal characteristics of the signals, indicating a strong influence of the environmental settings of the measurement sites on the temporal fluctuations of magnetic field H. Such results highlight the usefulness of the MF-DFA in discriminating dynamics in observational time series of magnetotellurics.

► Multifractality of magnetic component of the MT field measured in Taiwan was studied.
► The multifractal spectrum is wider for signals measured in low seismicity sites.
► The multifractal spectrum is narrower for signals measured in highly seismic sites.
► Possibly wider spectrum could be due to hybrid crustal and oceanic effects.
► The multifractality is a discrimination method of the site effects.