The 1931 Zangezur earthquake occurred on April 27 at 20:50:45 local time with a moment magnitude of 6.5.

The earthquake was located in the Zangezur Mountains near the boundary between southwestern Armenia and Azerbaijan's exclave, the Nakhichivan Autonomous Republic.

[4] The fault was also the source of the magnitude 7.5+ 1139 Ganja earthquake; the largest and most destructive seismic event in the Caucasus.

[9] There was a period of increased earthquake activity in Armenia and its neighboring republics between 1911 and 1956 and the 1931 event was one of the strongest.

It released about half of the total energy of all the earthquakes occurring in the Caucasus region near the Caspian Sea in that period.