The presence of pillow lava is evidence of what volcanic circumstance? 
1. a submarine volcano 
2.high silica content magma 
3.an explosive eruption 
4.a phreatomagmatic eruption 
5.caldera formation

A glowing cloud of hot gases and volcanic pieces: 
1.was named in Hawaii because it's so common there. 
2.is called a pyroclastic flow or nuée ardente. 
3.is so rare, none occurred all last century. 
4.is associated with shield cones. 
5.all of the above are true.

A lahar is: 
1.a glowing cloud of pyroclastic grains and hot gas. 
2.a cinder cone. 
3.an enlarged volcanic crater. 
4.a volcanic mud and debris flow that resembles fluid concrete. 
5.a lava lake in a summit crater.

The enlarged volcanic craters at Yellowstone, Crater Lake, and Krakatau are: 
1.evidence of safe, nonexplosive activity. 
2.called lahars. 
3.filled with columnar joints. 
4.formed by both explosion outward and collapse inward of the mountain. 
5.evidence of low silica content.