April 1923 Kamchatka earthquake and tsunami

April 1923 Kamchatka earthquake
Map of the Kamchatka Krai. Epicenter marked as a bullseye.
UTC time1923-04-13 15:31:07
ISC event911331
USGS-ANSSComCat
Local dateApril 14, 1923 (1923-04-14)
Local time02:31
Magnitude6.8–7.3 Ms, 7.0–8.2 Mw
Depth15 km
Epicenter56°34′N 163°02′E / 56.56°N 163.03°E / 56.56; 163.03
Areas affectedKamchatka, USSR (present-day Russia)
Max. intensityMMI X (Extreme)
TsunamiUp to 30 meters
Casualties36 dead

On April 14, 1923, at 02:31 local time, an earthquake occurred off the northern coast of the Kamchatka Peninsula in the USSR, present-day Russia. The earthquake had a surface-wave magnitude (Ms ) of 6.8–7.3 and an estimated moment magnitude (Mw ) of 7.0–8.2. This event came just two months after a slightly larger earthquake with an epicenter struck south of the April event. Both earthquakes were tsunamigenic although the latter generated wave heights far exceeding that of the one in February. After two foreshocks of "moderate force", the main event caused considerable damage. Most of the 36 casualties were the result of the tsunami inundation rather than the earthquake.