There is one more unique sight of Kronotsky preserve – a big hollow with the dimensions 9x12 km., and total area 150 sq.km., formed on the remain of the ruined volcano and called Volcano Uzon Caldera.
Hydrothermal activity is concentrated on the five thermal sites in the Southwestern part of the caldera. It manifests itself in numerous boiling and seething craters, countless mud cauldrons and small volcanoes, steaming or warmed sites with the gushes of steam or hot water. There are about 100 springs and more than 500 single hydrothermal appearances practically of all types of Kamchatka’s waters.
The biggest, and at the same time the coldest and shallowest among the lakes of the caldera is Centralnoye. Lake Fumarolnoye is warm: it is never covered with ice. Lake Bannoe with the temperature 40 C above zero even in winter, has the false bottom: the crust is formed by melted sulphur located in the depth. Lake Utinoye is cold, it has the unique sulphury beach. The warmth of the ground attracts animals and birds. There is much waterfowl on the on the thermal sites. Here the snipes, mute swans, and various species of ducks make their nests.
Hiking paths in Volcano Uzon Caldera are similar to those in the Valley of Geysers. Volcano Uzon Caldera is a unique because here it is possible to watch at the same time the appearances of new volcanic activity, the generation of minerals and ores, the formation of thermal lakes, the exposures of the youngest in the planet oil, and the microbiological activity in the thermal springs.

Helicopter Excursion Outline – Geyser Valley (Geyser Valley& Uzon Caldera):

• Departure from the airport “Avachinsky” to the Valley of Geysers, the flight includes flying around active volcanoes, the Karymsky volcano and the Maly Semyachik volcano with the Acidic Lake inside (flight time – 1 hour 15 minutes
• Landing at the Valley of Geysers. 5-10 minutes for rest and toilets.
• The observation of the after-effects of the mud slide.
• 1 hour 30 minute walking-tour with a guide along the 5th, 6th, 7th sections of the Valley of Geysers. On the 5th section tourists can observe the after-effects of the mud slide, the flood of the river Geysernaya, the submerged crater of Geyser Big. On the 6th section tourist are sure to watch eruptions of the following sources: the spring Malakhitovy Grot (Malachite Grotto), the spring Averi, Geyser Novy Fontan (New Fountain), Geyser Fontan (Fountain), Geyser Nepostoyanny (Unsteady), Geyser Dvoinoy (Double). There is an opportunity to watch eruptions of such Geysers as Shchel (Slot), Velikan (Giant), Zhemchuzhny (Pearly): the cycle of these geysers is rather long – Shchel (once in 30 min.), Giant (once in 4-10 hours), Pearly (once in 4-5 hours); as to Geyser Grot (Grotto), it erupts once in several years. According the statistics, only 2 of 10 groups are able to watch their eruptions.
• In case of Geyser Valley & Uzon Caldera:
• Flight to the caldera of the Uzon volcano.
• Walking-tour along the Eastern thermal field (1 hour). Bannoye Lake (which consists of sulfur), cauldrons with hot water, springs with colonies of carbothionic bacteria (taking part in the process of sulfuric acid formation). Khloridnoye Lake (consists of chloride and sodium, includes sulfuric beach), clayey volcanoes, mud cauldrons: The Sculpture cauldron.
• Flight on the Zhupanova River, hot lunch in the tourist centre.
• Departure to the airport “Avachinsky”(flight time – 35 minutes).