Underlying mechanism of precursory activity from analysis of upward earthquake migration

O. A. Molchanov
2011 Natural Hazards and Earth System Sciences  
In this paper we analyse the upward earthquake hypocentral migration in the ten known subduction zones and discuss a possible mechanism of such migration. The total time of the migration appears to range from 2.5 to 10 years. It leads to the estimation of the average velocity V z ∼ 60 − 300 km yr −1 . It probably corresponds to the movement of the forcing agent like stress or deformation wave from depths of the upper mantle (600-700 km) to the level of the lithosphere with subsequent initiation
more » ... bsequent initiation of fluid migration inside the crust to trigger shallow earthquakes. Averaged over all zones upward migration travel time is about 5 years (< V z >≈ 120 km yr −1 ) that coincides approximately with the period of characteristic temperature variation (El Nino) and crustal seismic periodicity in the Pacific region. These findings are helpful for the study of the seismic precursors and analysis of earthquake triggering. Published by Copernicus Publications on behalf of the European Geosciences Union.
doi:10.5194/nhess-11-135-2011 fatcat:hgswnzg3xzhihjpeb5ysxxre54