Speaker
Description
Previous studies [1] reported statistically significant correlations between variations in secondary cosmic-ray detection rates and global seismic activity, with the strongest correlations observed when seismic data are shifted by approximately two weeks relative to cosmic-ray data. The main characteristics of this cosmo-seismic effect will be presented and discussed.
Motivated by the sensitivity of these correlations to the initial observation time, periodicities in seismic activity were investigated. Analysis of global earthquake catalogs revealed a pronounced weekly structure characterized by a clear Sunday maximum and a broader Sunday–Monday–Tuesday pattern.
To test whether this structure could arise from statistical fluctuations, the earthquake data were first declustered, i.e. dependent events such as aftershocks were removed. Its statistical significance was then evaluated using bootstrap simulations with synthetic catalogs generated under a homogeneous Poisson assumption. The results indicate that the observed structure is highly unlikely to arise from random fluctuations.
To further understand this result, the possibility of an anthropogenic origin of the observed weekly structure is also being investigated, including both human-induced seismicity and variations in earthquake detectability associated with anthropogenic seismic noise. The results of these tests, together with the statistical analysis of the weekly structure, will be presented. The origin of both the cosmo-seismic correlation and the weekly periodicity in global earthquake occurrence remains an open question.