Numerical simulations of tsunamis generated by underwater volcanic explosions at Karymskoye lake (Kamchatka, Russia) and Kolumbo volcano (Aegean Sea, Greece)

Abstract

Abstract. Increasing human activities along the coasts of the world provoke the necessity to assess tsunami hazard from different sources (earthquakes, landslides, volcanic activity). In this paper, we simulate tsunamis generated by underwater volcanic explosions from (1) a submerged vent in a shallow water lake (Karymskoye Lake, Kamchatka), and (2) from Kolumbo submarine volcano (7 km NE of Santorini, Aegean Sea, Greece). The 1996 tsunami in Karymskoye lake is a well-documented example and thus serves as a case study for validating the calculations. The numerical model reproduces realistically the tsunami run-ups measured onshore. Systematic numerical study of tsunamis generated by explosions of the Kolumbo volcano is then conducted for a wide range of energies. Results show that in case of reawakening, the Kolumbo volcano might represent a significant tsunami hazard for the northern, eastern and southern coasts of Santorini, even for small-power explosions.

Source mechanisms of volcanic tsunamis

“…However, the effect of dispersion is reduced for underwater explosions occurring in shallow-water lakes, as the length-to-depth ratio of the waves rapidly increases and run-up inland can be locally high. This effect was particularly illustrated by the 19 m run-up at Karymsky Lake, Kamchatka, in 1996 [12,106,109].…”

“…It is worth noting that many volcanic eruptions starting below the water surface are not tsunamigenic, including Surtseyan-type phreatomagmatic eruptions [12]. Compared with other sources of underwater explosions, magma-water interactions are complex and their physics ) 1996 aerial photographs of the northern part of Karymsky Lake, Akademiya Nauk caldera, Kamchatka (courtesy of A. Belousov and M. Belousova).…”

Unraveling Past Submarine Eruptions by Dating Lapilli Tuff-Encrusting Coralligenous (Actea Volcano, NW Sicilian Channel)

“…Tsunami waves may be produced by a series of events like volcano-tectonic earthquakes, volcano flank collapses and landslides, entrance of pyroclastic flows under the sea, underwater explosions and sudden ground movements at volcanoes (e.g., Paris, 2015). Although underwater explosions, including Surtseyan-type phreatomagmatic eruptions, typically generate short-term, large-dispersion waves compared to earthquakes, with a general limited far-field impact, wave run-up inland can be locally high, especially in narrow bays (Ulvrova et al, 2014). The hazard associated with these phenomena is quite unpredictable, and could in many cases be underestimated.…”

Multilayer modelling of waves generated by explosive submarine volcanism

“…While experimental data and detailed field studies of these phenomena are rare, some reliable observations exist, for example, at Karymskoye Lake, 1996, where a Surtseyan-style eruption was partially witnessed from the air including six explosions followed by tsunamis and base surges. Later ground investigation revealed run-up along the lake ranging from 19 -1.8 m at distances 0.5 -3 km from the vent, debris flows down the Karymskaya River, and boulder transportation up to 60 m inland (Belousov et al, 2000;Torsvik et al, 2010;Ulvrová et al, 2014;Falvard et al, 2018). The Ritter Island volcano generated one of the largest known tsunamigenic flank collapses in 1888, leaving only a small remnant above the water surface, and has since experienced occasional submarine eruptive activity and small local tsunamis in 1972in , 1974in and 2007in (Johnson, 1987Dondin et al, 2012).…”

“…The current theoretical models summarised by Le Méhauté and Wang (1996) have been used in recent years to simulate the wavefield generated from events that produce analogous water surface cavitation such as submarine volcanic explosions (Torsvik et al, 2010;Ulvrová et al, 2014; and asteroids impacting in ocean 2 https://doi.org/10.5194/nhess-2021-109 Preprint. Discussion started: 7 July 2021 c Author(s) 2021.…”