by CKR
I usually do this kind of thing on Tuesdays, but yesterday just got away from me.
Kamchatka has 29 active volcanoes in its 900-kilometer length. We visited several of the volcanic areas and flew over others. We were told at the Institute of Vulcanology that Kamchatka has several types of volcanoes, both andesitic volcanoes that result from subduction of the earth's crust and stratovolcanoes that have other causes. Look at the map: you'll see that a deep trench in the ocean parallels Kamchatka's eastern coast. That's where oceanic crust is being drawn under Kamchatka. 
This is the Valley of the Geysers in Kronotsky Reserve. It was discovered only in 1941. Great flowers as well as geysers like Yellowstone's, and we even saw a grizzly bear munching on Herculaneum, a wonderful gigantic plant that I failed to get photos of. It was one of those things that is so pervasive that I took it for granted. Have to go back, I guess.
I think these are the Avachinsky and Koryaksky volcanoes, 2751 and 3456 m high (9026 and 11,339 feet). Avachinsky is only 30 kilometers from Petropavlovsk and started smoking while we were there, but the Institute people said no eruptions were expected.
Volcanic eruptions are easier to predict than earthquakes, because seismometers and other devices can measure the underground movement of lava directly.
The Novy Tobalchik volcanic field was formed in a series of eruptions during 1975-76. The cinder cones are very much like Hawai'ian volcanic fields. Arctic poppies, forget-me-nots, and a small saxifrage were blooming. There was a white crust on the ground that I thought was soluble minerals leaching out, but it was moss. Lots of lichens and liverworts, too.
You wouldn't want to swim in this lake. That lovely color is from the hydrochloric and sulfuric acids, 1.4 pH. That's as acid as anything I've used in the laboratory. It's usually about 40 C (100 F), too. I'm wondering what's floating on the surface: probably pumice fragments clumped into rafts. It's at the top of Maly Semyachik Volcano.