picture
2: Mount Saint Helens (USGS, 1980)
Mount Saint Helens, Kilauea, Fugi, Vesuvius, and Tambora are some of the worlds most famous volcanoes. But one thing some people don't know about these volcanoes would be that they have had multiple large and small scale eruptions in history. Why do these volcanoes erupt multiple times and not other places in Earth's curst miles away?
This happens because of the propagation of dikes. Dikes are intrusions of magma that propagate through the crust by a process called brittle failure. The dikes sometimes reach the surface as a volcanic eruption or sometimes never make it to the surface and solidify in the crust. Dikes that dont make it to the surface can be preserved and transported to the surface over thousands or millions of years, as you can see at schoodic point in Maine. The reason dikes propagate to volcanoes is because they propagate through brittle failure towards the area of most stress. The stress put on Earth's crust by the load of the volcano is the greatest stress around for miles so the dikes propagate to the volcanic mountain. The stress put on Earth's crust from the volcano is the reason large volcanic mountains have multiple eruptions over time while the surrounding areas do not have major volcanic eruptions.
| HOME |
INTRODUCTION |
BACKGROUND |
DATA |
RESULTS |
REFERENCES |