The most obvious landforms created by lava are volcanoes. These may be relatively small cinder cones or huge composite or shield volcano mountains. Sometimes lava erupts through a long crack, or fissure, instead through the vent of a volcano. The entire ocean floor is the result of fissure eruptions.     When lava is viscous, it flows slowly. Viscous lava typically causes explosive volcanic eruptions that form shield volcanoes. However, if there is not enough magma or enough pressure to cause an explosive eruption, the magma may form a lava dome instead. A lava dome is a large, rounded... Show more

The most obvious landforms created by lava are volcanoes. These may be relatively small cinder cones or huge composite or shield volcano mountains. Sometimes lava erupts through a long crack, or fissure, instead through the vent of a volcano. The entire ocean floor is the result of fissure eruptions.    
When lava is viscous, it flows slowly. Viscous lava typically causes explosive volcanic eruptions that form shield volcanoes. However, if there is not enough magma or enough pressure to cause an explosive eruption, the magma may form a lava dome instead. A lava dome is a large, rounded landform that forms when viscous lava cools and hardens before it can travel far from a vent. Lava domes often form in the middle of craters at the top of composite volcanoes. For example, there is a lava dome in the crater of Mount St. Helens.    
When lava is not viscous, it flows quickly. It can flow over an extensive area before it cools and hardens. This type of lava flow may form a lava plateau. This is a wide, flat surface of igneous rock that forms when thin lava solidifies.    
Lava may create new land by forming or expanding islands in the ocean. This occurs when lava solidifies on the coast or emerges from beneath the water. The Hawaiian Islands are formed from shield volcano eruptions and havegrown over the last 5 million years.    

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