Tectonic impact on the Lake Sevan environment (Armenia)

The geology of Lake Sevan is characterized by the structure of a pull-apart basin. Methane emission from the lake surface correlates with evidence of physical and chemical water properties, remote sensing, etc., and suggests its possible emission from active fault zones at the lake bottom, as well a s emission of biogenic methane from the fermentation of bottom organic rema ins. Correlation with anomalies in the lake bottom geochemistry suggests a high permeability of active fault zones and suggests that geodynamic, seism ic and geochemical activity across the fault zones during the buildup to th e M = 7.1 Spitak earthquake led to plankton depression, which resulted in a large number of fish dying in 1984, and ended with a seismic disaster in 1 988.