Detection of Long-Range Correlations and Trends Between Earthquakes in California

Document Type : Research Note


1 Alzahra University

2 International Institute of Earthquake Engineering and Seismology


In this paper, we investigate the long-range correlations and trends between
consecutive earthquakes by means of the scaling parameter so-called locally Hurst
parameter, H(t), and examine its variations in time, to find a specific pattern that
exists between Earthquakes. The long-range correlations are usaully detected
by calculating a constant Hurst parameter. However, the multi-fractal structure of
earthquakes caused that more than one scaling exponent is needed to account
for the scaling properties of such processes. Thus, in this paper, we consider the
time-dependent Hurst exponent to realize scale variations in trend and correlations
between consecutive seismic activities, for all times. We apply the Hilbert-Huang
transform to estimate H(t) for the time series extracted from seismic activities
occurred in California during 12 years, from 2/24/2007 to 9/29/2017. The superiority
of the method is discovering some specific hidden patterns that exist between
consecutive earthquakes, by studying the trend and variations of H(t). Estimationg
H(t) only as a measure of dependency, may lead to misleading results, but using this
method, the trend and variations of the parameter is studying to discover hidden
dependencies between consecutive earthquakes. Recognizing such dependency
patterns can help us in prediction of future main shocks.