Photo: US Geological Survey
Runny basaltic lava (with low gas and silica content) produce small less explosive eruptions like those that formed Lava Butte (above), near Bend.
Oregon's rich volcanic diversity is a wonderful natural laboratory in which to learn about volcanoes. This window contains a graph showing how different volcanoes in Oregon relate to each other based on magma of different temperature and chemistry and different eruption volumes. Their different magmas create different recipes for eruption!
You can also view a road map showing where 20 of Oregon’s volcanic features are located. Learn how the different volcano types in Oregon have very different eruption sizes, from relatively small ones that blanket a few acres, to supervolcanic eruptions blanketing large parts of many counties!
Digging Deeper: For more information, visit these websites:
The US Geological Survey online pamphlet Volcanoes is an introduction to volcanism including different types of eruptions:
The USGS CVO has a website of frequently asked volcano questions:
Encyclopedia of the Earth: information on volcanic eruption types:
Learn about volcanoes in the United States and around the world at Volcano World: http://volcano.oregonstate.edu/
Digging Deeper: For more information, give this sample of books a read:
Geology of Oregon, 5th Edition by Elizabeth L. Orr and William N. Orr (2000, Kendall/Hunt
[http://www.kendallhunt.com/]) Professors at the University of Oregon, the Orr’s have been writing about Oregon’s geology for decades.
In Search of Ancient Oregon by Ellen Morris Bishop (2003, Timber Press
[http://www.timberpress.com/]) Take a photographic journey through time and see Oregon’s ancient places.