| A | B |
|---|
| composite | formed by alternating layers of lava and tephra |
| cinder cone | formed by loose layers of tephra |
| shield | formed by flat layers of silica-poor lava |
| silica-rich | thick and explosive |
| silica-poor | thin and fluid |
| sill | magma that hardens after being forced into a crack parallel to rock |
| pyroclastic flows | can bury cities and towns in their paths |
| magma at convergent boundaries | can contain a lot of water vapor |
