Into a Distant Light
The Indians named Mt. Rainier appropriately Tahoma, the Snow Mountain. Both rim craters are filled with several hundred feet of snow including a network of ice caverns and a pool of meltwater under the ice due to nearly boiling temperatures in the vents. Annual snow accumulation of about 100 ft (30 m) nourishes 26 glaciers. Stratovolcanoes are composite volcanoes as they grow during short but violent eruptive events producing lava flows that alternate with pyroclastic eruptions of tephra causing ash fall and pumice. Relatively long phases of dormancy are followed by the next eruption cycle giving the volcano a layered structure. Mt. Rainier along with the Cascade Range volcanoes belong to the Ring of Fire that encloses the Pacific Ocean. Volcanoes of that type usually contain intermediate to high silica magma resulting in explosive lava types called andestite and ryolihte. Silicate rich magma behaves like a thick paste and reduces the ability of gas to escape. This builds-up high pressure within the volcano that is suddenly released when the surrounding rocks break leading to explosive eruptions.
August 2008
Canon 20D, Canon 10-22mm, f/16, 8 sec, ISO 100, tripod