M 5.6 - 8 km SE of Khowy, Iran

Tectonic Summary

The October 5th, 2022 Iran, earthquake occurred as the result of shallow oblique reverse faulting near the Iranian-Turkish border. Focal mechanism solutions indicate that rupture occurred on a steeply dipping reverse fault striking to the northeast, or a moderately dipping reverse fault striking to the west-northwest. The location and depth of the earthquake indicate that this is an intraplate event, occurring within the broadly distributed plate boundary zone between the converging Arabia and Eurasia plates. The Arabia plate moves northward relative to Eurasia at the location of the October 5 earthquake, forming the Northern Zagros, Bitlis, and Caucus Mountain ranges, and helping to drive the Anatolia microplate (Turkey) westward into the Aegean Sea.

Moderate magnitude, shallow earthquakes like the event on October 5 are common in Iran, while large (magnitude 7 or greater) are relatively rare; nevertheless, moderate magnitude earthquakes in this region are commonly destructive and deadly owing to regional infrastructure. In the past 100 years, 36 other earthquakes M5.5 and larger have occurred within 250 km of the October 5th, 2022 event, including three earthquakes M7 and larger. In 2011, an M7.1 earthquake occurred 135 km to the northwest near Van, Turkey, and resulted in at least 650 fatalities and displaced more than 40,000 people. Before the advent of modern seismological monitoring equipment, an earthquake of approximately magnitude 7.4 struck the city of Tabriz in 1780, resulting in an estimated 50,000 fatalities.