Russian Academician Postulates a Seismicity-Climate Connection

O. Molchanov of the Russian Academy of Sciences' Institute of the Physics of the Earth -- which is headquartered in Moscow, Russia -- makes a case for the hypothesis that, at least partially, global climate changes and corresponding activity indices such as the ENSO phenomenon are induced by similar variations in seismicity." This was done by (1) calculating the cumulative annual seismic energy released by large earthquake events originating from depths of 0 to 38 km, based on data archived by the U.S. Geological Survey for the 35-year time interval of 1973-2008 for various earthquake activity zones spread across the tropical and western Pacific -- including the Chilean subduction zone, the Tonga-Kermadec zone, the Sunda, Philippine, Solomon Sea zones and the Mariana, Japan and Kuril-Kamchatka zones -- and (2) comparing the then-evident periodicity of seismic energy production with that of sea surface temperature oscillations that occurred over the same 35-year period within the Niño zones 1+2 (0-10°S, 90-80°W), 3 (5°N-5°S, 150-90°W), and 4 (5°N-5°S, 160°E-150°W).

Based on their analysis, it was determined, first of all, that (1) the "climate indices show expected ENSO variation," and "amazingly," as Molchanov describes it, that (2) the earthquake indices demonstrate "similar quasi-ENSO variations." So the next questions were obviously: (1) which is the action? ... and (2) which is the reaction? From a number of other factors considered by the Russian researcher, he concludes that it is "more probable" that earthquake activity is "forcing the ENSO variation in the climate" than vice versa.

In concluding his paper, Molchanov states that "trends in the climate and seismic variations are similar to each other," and that "it is rather probable that the climate ENSO effect is at least partially induced by seismicity with a time lag of about 1.5 years," leaving it up to others to further study and debate the issue.