South_Sister

South Sister SOUTH SISTER Redmond Oregon is where my brother lives. The town is located near the Oregon’s cascade range where there are several large snow covered volcanoes. I well be focusing on the south sister, which is the youngest and highest of a trio of closely grouped volcanoes called the three sisters. The south sister could be a threat to my brother because he lives only a few miles away, and according to sources the volcano may be coming to life. South sister is a composite volcano 10,358 feet high, it cone is comprised of adesite, dacite and rhyodacite, and is relatively young compared to its neighboring volcanoes. The latest eruptions on south sister occurred in two closely spaced episodes about 200 years ago. The eruption was a modest eruption producing small pyroclastic flows and tephra. But preceding that, similar style eruptions up to ten times larger occurred during and just before the last ice age 30,000-15,000 years ago. These larger eruptions produced pyroclastic flows that covered over a very large area from sisters to bend(see map) and tephra fallout deposits as thick as 42 feet. Such an eruption would be catastrophic today due to the mass population located near the base of sister, south, brother, eruption, volcanoes, area, volcano, say, eruptions, about, years, usgs, tephra, swelling, sisters, scott, rock, molten, miles, magma, large, flows, enough, danger, bulge, ash, around, ago, 2002, year, very, two, time, three, survey