Magma may slowly flow out as a thick liquid, called lava, or it may explode as solid or liquid pieces, called volcanic bombs. Lava cools after it flows from the volcano and builds up to form a hill or mountain around the hole. Mauna Loa is called a shield volcano, its lava slowly flows from the vent to form a gently sloping hill. Volcanoes with more gas and thicker lava are usually more explosive than the Hawaiian type. Many times these are blown high into the air.
Volcanic bombs can be just ash or as big as convenience stores.
The planet Mars has Hawaiian type shield volcanoes too. Home, Letters, Links, Index of Photos, Maps, Journal, Slide Show.