Some observations of atmosferic luminosity as a possible earthquake precursor

Abstract

Some sky radiation measurements in Mexico City suggest that anomalous values occur several days before a strong earthquake, both in the red and the green parts of the spectrum. The emissions appear to be intermittent and are chiefly detected by an increased variance of the hourly light intensity. Before and after the March 14, 1979 Petatlan, Mexico earthquake (M7.4), large fluctuations in sky luminosity were observed. In several instances the radiation intensity exceeded the standard value for a transparent atmosphere. We suggest that the high readings are due to radiation in the visible spectrum which originates in the earth and is reflected by the haze and the cloud cover.