Energetic analysis of global topography

Abstract

Diagrams of the various distributions of the potential energy of the continental and oceanic-bottom topography as a quantitative indices of energy consumption by tectonic processes have been calculated and plotted for the first time on the basis of high-resolution ETOPO 2′ digital data on a 2′ × 2 ′ uniform network with height intervals of 100 m. The potential energy of the continents and oceanic bottom is mainly stored in mountainous regions of Asia and South America with an anomalous type of energy distribution and in mid-oceanic ridges, respectively. The topography of the oceanic bottom bears five times more energy than the continental topography. With allowance for the isostatic compensation of denudation, the bulk reserve of the potential energy of the global topography is estimated at 1033 erg, a value which amounts to only an insignificant fraction of other items in the energetic budget of the Earth. Fifty percent of this energy has been gained over the last 70 Ma. Currently, the rate of accumulation of the potential energy of the topography is 1025 erg/yr, i.e., 1000 times less than the bulk geothermal flow and 10 times less than energy released by all earthquakes during a year. So far, there are no grounds to bind the potential energy of the Earth’s topography with a specific source.