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1. Volcanic and Tectonic Landforms Landforms
Volcanic Activity
Landforms of Tectonic Activity
Earthquakes
9. one of the most catastrophic of natural phenomena is a volcanic explosion so violent that it destroys the entire central portion of the volcano
vast quantities of ash and dust are emitted and fill the atmosphere for many hundreds of square kilometers around the volcano
only a great central depression, named a caldera, remains after the explosion
10. Calderas
31. an important environmental hazard often associated with a major earthquake centered on a subduction plate boundary is the seismic sea wave, or tsunami
a train of these water waves is often generated in the ocean by a sudden movement of the sea floor at a point near the earthquake source
the waves travel over the ocean in ever-widening circles, but they are not perceptible at sea in deep water