Prediction of lateral eruption of Klyuchevskoy volcano in March 1983

Abstract

A swarm of volcanic earthquakes began on February 28, 1983 with their epicentres placed on the northeastern slope of Klyuchevskoy volcano and their foci located within the cone of the volcano at a height of 1–4 km above sea level. From the position of earthquake foci, the character of swarm development in time and the sharply decreasing activity of the Klyuchevskoy central crater, the author made a predicion according to which between 4 and 9 March and with the probability of 0.7, a lateral eruption should occur on the northeastern slope of the volcano. On March 4–5, at the direction of the Institute of Volcanology, all the institutions concerned and the population of Kamchatka were warned about the possibility of an eruption. The eruption commenced on March 8 two kilometres from the place predicted. Calm outpouring of lava of andesite-basaltic composition occurred without explosions from a newly formed crater. By April 6 the length of the lava flow reached about 3 km.