Historic Earthquakes

Notes about the Armenia Earthquake, 7 December 1988

The Earth's crust is a jigsaw of rigid plates like huge paving stones. According to the theory of plate tectonics, these lithosphere plates are constantly in motion, slowly realigning themselves with the passage of time. Ninety to ninety-five percent of all earthquakes occur where the plates collide with each other.

In Armenia, the Arabian plate abuts against the Eurasian (Europe-Asia) plate. As a result, the region has been plagued by severe earthquakes for thousands of years: an earthquake in 893 A.D. took an estimated 20,000 lives; another in 1667 took 80,000 lives

Whenever the plates moving beneath Armenia interlock, pressure builds. The stress increases, the pressure continues to climb and finally there is a fracture - a sudden release of energy we know as an earthquake.

Compiled from USGS press releases by Donovan Kelly and Don Finley

Abridged from Earthquakes & Volcanoes, Volume 21, Number 2, 1989.