Global View
Basaltic silica poor magma erupts from the Kileau volcano in October
2003. C. Heliker. (USGS Hawaii Observatory).With an understanding of plate tectonics, and now volcanoes, you are adding to your “geologic repertoire” of how the Earth works. Although you may not have to worry about out running lava flows in Indianapolis, worldwide volcanoes pose a significant risk to human populations. Both your textbook and our lecture point to evidence of how volcanic events can have global impacts.
The good news is geologists can predict with some certainty when a volcanic eruption may take place. The U.S. Geological Survey constantly monitors the volcanically active portions of the United States for signs of an upcoming eruption. Geologists have not come up with a strict classification scheme for whether a volcano can be dangerous. A general classification scheme follows:
- Active: Recent activity has been measured or an eruption has occurred in the last 200-300 years. Located in a plate tectonic setting that suggests continued activity.
- Dormant: No measurable activity, but evidence exists for activity in recorded human history years. Located in a plate tectonic setting that indicates the potential for continued activity
- Extinct: No activity in the last 2000-3000 years, or the volcano is not located in a plate tectonic setting that indicates future activity. However, extinct volcanoes can come back to life.
In the class Chat Room, answer this question: In the TV show Southpark, a geologist discovers a volcano erupting in the nearby mountains. Why wouldn’t you expect to find a volcano in the Rocky Mountains of Colorado today? What is the tectonic setting?
