Fig.1

Fig.2

Fig.3

Most people look at Taunshits volcano from southeast, and see a huge Late Pleistocene edifice, consisting of a large tuya pedestal, formed during the last glaciation, and a central cone loaded by several extrusive domes (Figs. 1, 2). Moraines dotted with abundant thermocarst lakes surround the volcano and form spectacular "Sinii Dol" ("Blue Plateau") south of it. However, Taunshits secret is hidden on its rarely visited western slope, which demonstrates traces of violent Holocene activity: a large horseshoe-shaped crater with an extrusive dome and lava flow inside (Fig. 3).

The volcano had frequent moderate eruptions in the very beginning of the Holocene. About 7700 ¹⁴C yrs BP a catastrophic eruption took place preceded by a failure of the western sector of the edifice. The landslide formed a horseshoe-shaped crater 1.5 km in diameter and a debris avalanche with travel distance of about 19 km and a volume of 3 km³. The debris avalanche deposits are overlain by stratified pyroclastic surge deposits, plinian fall-out and later pyroclastic flow and surge deposits.

The most recent eruption of Taunshits took place about 2400 ¹⁴C yr BP.  It was preceded by moderate activity in the mid-Holocene time associated with the growth of an extrusive dome in the crater of the 7700 eruption. The most recent activity began with a phreatic explosion followed by an eruption of andesitic material which formed pyroclastic flow and surge deposits, and then a lava flow (Fig. 3). Ash from this eruption can be traced over a vast territory between Kronotskoe Lake and Bol'shoi Semiachik massif. Holocene products of the volcano are dominated by hornblende-bearing mid-potassic andesites of the calcalkaline series.

The Taunshits eruptive history suggests that it still can resume its activity and produce hazardous pumice fallout and pyroclastic flows. However, it has never been included into catalogues of recent volcanoes, possibly because people looked at it from southeast.

 Literature

Leonov VL, Grib EN, Kartasheva LA (1990) On the structure and age of Taunshits volcano. Voprosy Geographii Kamchatki 10: 156-166 (In Russian)

Melekestsev IV, Braitseva OA, Ponomareva VV (1998) Taunshits volcano, Eastern Kamchatka: a newly recognized potentially active and hazardous center and its past catastrophic eruptions. Colima volcano Sixth International Meeting. University of Colima, January 26-30 1998