Towards Evidence of Long-Range Correlations in Shallow Seismic   Activities
  In this work, we introduce a new methodology to construct a network of epicenters that avoids problems found in well-established methodologies when they are applied to global catalogs of earthquakes located in shallow zones. The new methodology involves essentially the introduction of a time window which works as a temporal filter. Our approach is more generic and for small regions the results coincide with previous findings. The network constructed with that model has small-world properties and the distribution of node connectivity follows a non-traditional function, namely a q-exponential, where scale-free properties are present. The vertices with larger connectivity in the network correspond to the areas with very intense seismic activities in the period considered. These new results strengthen the hypothesis of long spatial and temporal correlations between earthquakes. 
Douglas S. R. Ferreira, Jennifer Ribeiro, Andr\'es R. R. Papa, Ronaldo   Menezes
physics.geo-ph cond-mat.stat-mech