When the hotspot under McDermitt (Nevada-Oregon) exploded fifteen million years ago it left a large caldera behind. With the North American Plate moving west-southwest over the stationary hotspot deep underneath, the successive eruptions formed a chain of calderas creating the eastern Snake river plain. 
One of the obvious places of this event is Crater of the Moon national preserve, where the hotspot was situated 10 to 11 million years ago. For one afternoon I wander around cinder cones, spatter cones and old lava streams. 
Today the hotspot is situated beneath the popular Yellowstone National Park. About 630.000 years ago the super eruption taking place here, left the Yellowstone Caldera behind. Inside the caldera groundwater heated by the under laying hotspot, bubbles in all kinds of ways to the surface. The first thing to do when I arrive is to wait for the eruption of the Old Faithful geyser. Geysers are hot springs with constriction in their plumbing system to allow pressure to build up, causing an eruption. Old Faithful is erupting every 90 minutes or so and shoots about 20.000 liter of water 35 meters in the air. Its pretty cool and I can see why I am not the only one waiting.
The following 2 days I check out the rest of the geysers in the park. 
Admire all the marvelous colours of the distinctive bacteria growing in different temperature regions inside the hot springs. 
And walk by different mudpods and fumaroles.
Its a beautiful national park and my head is filled with fumes and wonderful impressions. Its time to relax for a while, I am going on vacation.Dag,
Iris (Jackson hole, 14207 miles)
