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Abstract
This paper is a brief description of a proposed tectonophysical interpretation of the isostatic anomaly in Colombia, as determined in 1943 by few scattered pendulum observations (Aslakson-Swick). It is suggested that: a) The anomaly high reflects the upthrusting of the denser sima over the lighter sial (R. A. Daly- W. H. Bucher); b) That this overriding has taken place over the east dipping master fault determined by earthquake foci (Gutenbe,rg-Richter, Benioff), and c) That, this thrust is actually a double plane aurfaee or zone, with an abrupt change of dip at depth of 70 to 100, km., corresponding to the no-strain or neutral level of professor J. T. Wilson's model of the world tectonic ares. The thrust's dip break is suggested by the peculiar spacial distribution of earth quake foci (seismic isobaths)
References
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