Volcanic Eruptions
Types of Lava
There are three different types of Mafic lava; Pahoehoe,Aa, and Blocky lava.
Mafic magma has a low viscosity meaning the lava moves much slower. It contains magnesium and Iron. It has less trapped gases and is dark in color. Mafic lava causes quiet eruptions.
Pahoehoe
Pahoehoe is the least viscous type of Mafic lava. It forms wrinkly volcanic rock when it cools.
Aa
Aa lava is more viscous than pahoehoe lava and forms sharp volcanic rock when it cools.
Blocky Lava
Blocky lava is thick vicious lava that does not travel far front the erupting vent. It forms chunky volcanic rock when it cools.
Shield Volcanoes
Volcanic cones that are broadat the base and have gently sloping sides are called Shield volcanoes. It covers a wide area and. Generally forms from quiet eruptions. Layers of hot lava flow out around the vent,harden and slowly build up to form the cone.