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.

[7] The earthquake occurred off the Kamchatka Peninsula's east coast, which runs parallel to the Kuril-Kamchatka Trench, the area where the Pacific and Okhotsk Sea plates converge.

Being older and therefore denser, the Pacific subducts beneath the Kamchatka Peninsula, which sits on the Okhotsk Sea Plate.

[6] In another study by Bourgeois and Pinegina published in 2018, the source area of the April earthquake is north of the February rupture but southwest of Bering Island and in Kamchatka Bay [ru].

However, a study published in Pure and Applied Geophysics found that no numerical modelling of the earthquake could reproduce the unusually large tsunami.

Despire confirming the tsunamigenic earthquake source characteristic using the available seismograph readings, it did not account for the local tsunami observations.

[16] Fifteen minutes later, an 11 m (36 ft) wave began advancing onshore, washing away structures at a nearby settlement and flowing upstream by 7 km (4.3 mi) on the Kamchatka River.

[18] A small cutter belonging to the Nichiro cannery was found 1–2 km (0.62–1.24 mi) inland, 30 m (98 ft) above sea level.

The extent of damage decreased abruptly eastwards along a 10 km (6.2 mi) portion of a spit that separated Lake Nerpichye from Kamchatka Bay.

On the United States west coast, a 0.15 m (5.9 in) wave was recorded at San Francisco while at the Port of Los Angeles, some swirls were observed between 06:00 and 10:00.

Some of the remaining inhabitants of Ust-Kamchatsk later founded the village of Krutoberegovo [ru] because the tsunami had badly affected the main city.

[21] The Los Angeles Times on 15 April reported that flooding in the Korean of city Busan caused over 1,000 deaths.

[6] Meanwhile, the Sydney Morning Herald on 16 April claimed that 400 people went missing due to a tidal wave in the same city.