Analysis of related seismic events by the orgraph theory methods
For samples from the earthquakes catalogues with large seismic events the components of unilateral relatedness of corresponding
orgraphs are studied. Definition of new mathematical adjectives is proposed - octopus-index of orgraph vertexes. Dynamics of this
value changes can be used in algorithms of medium-term forecast. Test examples and results of test calculations for the
earthquakes of North California and the Crimean-Black Sea region have been given.