Brain activity vs. seismicity: Scaling and memory

TL;DR

This study compares brain activity and seismicity, revealing that seismic events are nearly memoryless while EEG fluctuations exhibit long-term memory, using a new method to evaluate process memory.

Contribution

Introduces a novel quantitative method to assess (non-)Markovianity, applied to seismic and EEG data to distinguish their memory properties.

Findings

Seismicity processes are nearly memoryless.

EEG fluctuations exhibit long-term memory.

New method effectively evaluates process memory.

Abstract

The brain activity and seismicity share a remarkable similarity. The Gutenberg-Richter law describing a power-law relation between the frequency of earthquake occurrence and released energy has its counterpart in the brain activity of a patient with epilepsy, that is, the distribution of fluctuations of the voltage difference measured by electroencephalogram (EEG) also obeys a Gutenberg-Richter-like power law. The similarity in the distributions, however, does not directly tell if the processes underlying these intermittent phenomena are also similar to each other. Here, a new simple method is presented for quantitative evaluation of (non-)Markovianity and is applied to the processes of released energy in seismicity and fluctuation of the voltage difference in EEG data. It is shown that the process in seismicity is almost memoryless, whereas that in EEG has long-term memory.