More photographs of Maly Semiachik volcano
Maly Semiachik wears the usual cloud as a hat; the valley of the Karymsky River is in the foreground. "Maly" means little, with an elevation of 1,560 m I'd rather call it medium.
The Troitsky Crater in the summit region is the only active crater and between 800-900 m wide. It is completely filled with warm acidic water. For two times in history, in the middle of the 19th and 20th centuries, witnesses observed intense steam formation and ash clouds above the crater. A big eruption must have taken place 500 years ago, while native people claim another significant eruption to the year 1804. Judging from the look of the surrounding area all this could be true.
The crater lake is obviously heated by direct injection of fumarolic gases down on the bottom. Its water is extremely acidic for a natural lake and has a pH of less than 1. As already said the temperature changes in the range of around 30-40 deg C depending mostly on volcanic activity; the air above the crater feels warm and has a smooth hellish smell.