March 30, 1956 Tsunami: Kamchatka, Russia

A gigantic explosion of Bezmianny Volcano on Kamchatka, Russia, produced a shock wave or air wave that struck the coastal waters of Kamchatka. It created an air pressure wave that coupled with the sea and was widely recorded throughout the Pacific Basin. No signals were recorded on barographs operated by the U.S. Weather Bureau in the Pacific or on the west coast of the United States. (Reference #237)

Note the following Lander and Lander, et al.: Ref #236 lists the event as a validity 4 (definite tsunami); Ref #237 lists validity 2 (possible tsunami) as a tsunami wave since the wave creation was not “instantaneous”; Ref #239 lists validity 1 (probably not valid tsunami)

A similarly great eruption occurred in Kamchatka on March 30, 1956, from the volcano Bezymianny (= "Nameless"), after thousands of earthquakes of volcanic origin, however, without caldera collapse. At any rate, the top of the mountain was perfectly destroyed. The trees of the forest up to a distance of 30 km were uprooted due to the air blast. The air-shock took a circle around the Earth as a whole. In the course of the analysis of our system of tsunami and eruption data we perceived an interesting correlation that was unknown earlier. Namely: the coordinates of Bezymianny are 55058.3' N, 160°35.2'E, and those of the source of the tsunami are 550 N, 160°54' E. In Universal Time the explosive eruption began at 06h 11m 05s, and exactly the same time is given by Iida et al. for the origin of the tsunami. These data demonstrate clearly that the tsunami was due to the explosion. Consulting Rothe's (1969) catalog as well as the Catalog of Epicenters for the Year 1956, we have not found any earthquake for the place and time mentioned above. We mean, of course, tectonic shocks. Therefore it is concluded that the tsunami was generated directly, not by a tectonic displacement due to the eruption, but by the air waves that accompanied the explosion itself, similar to those tsunamis at Krakatau which resulted from the explosions, as mentioned above. (reference #13564)

A small tsunami, widely recorded on tide gauges in the Pacific, with a maximum amplitude of 30 cm at Attu Island (Iida et al., 1967), was probably generated by the air waves of the explosion (P. Hedervari, personal communication, 1980) in the manner first suggested by Ewing et al., 1955, and elaborated by Hedervari al. (1967).

Reference #12345 (accessed August 2023) lists validity 4 (definite).