BC) thought fire was at the root of everything and assumed volcanoes caused earthquakes Aristotle (ca 400 BC) considered earthquakes were the result of “dense air and vapors” within Earth The Chinese mathematician and astronomer Chan Hen constructed the first seismoscope in AD 132
of mudslides that destroyed everything in their path The eruption also spurred a huge growth in volcanology In the decade after the blast, the USGS established volcano observatories in the Pacific Northwest, Hawaii and Alaska Funding for the USGS’s volcanic hazards programme today is nearly ten times what it was before the Mount St Helens
Volcanology and Geology FIELD OF RESEARCH Steve’s interest in volcanoes spans more than 40 years Much of his work is concerned with lava-producing super-eruptions (which occurred on Earth millions of years ago) and explosive super-eruptions (which can and will occur again during the human species’ lifespan) National Science Foundation, USA;
1 Volcanology is the study of volcanoes Volcanologists are the people who study volcanoes 2 a Composite: These volcanoes are typically tens of miles across and ten thousand or more feet in height They have moderately steep sides and sometimes have small craters in their summits Volcanologists call these “strato-“ or composite volcanoes
burying everything in their path First recognized at Mount St Helens, but now known to be a very common process on all types of volcanoes (Mount Shasta, Hawaii) Debris avalanche deposits on a volcano in Chile All of the area in the foreground is buried by a thick debris avalanche Close - up note the boulders and rubble in the cliff
4 Some Volcano Facts The total number of recognizable volcanoes is about 10,000 ACTIVE – volcanoes known to have erupted during historical times
Volcanologists also study the past, The old eruptions and how long they last Volcanoes leave lots of deposits behind Made up of residue of all shapes and kinds