88 The Heat of Kilauea-Low

The Heat of Kilauea FOCUS Question What is the connection between volcanoes and heat energy?

Magma on the Move Deep inside Earth, it is so hot that rocks melt! The melted rock found beneath Earth's surface is called magma. On occasion, magma makes its way up to Earth's surface, where it can form mountains called volcanoes. Once magma reaches the air, it is called lava. In some volcanoes, lava spews out in a fountain of fire. At other times, it oozes like thick syrup. One well-known volcano is named Kilauea. This active volcano is still expanding in the Pacific Ocean and forms part of the state of Hawaii. In fact, it is part of the state's largest and newest island, also called Hawaii, or the Big Island. Word Wise The name Kilauea means "spewing" in the Hawaiian language.

Volcano Variety Kilauea is classified as a shield volcano. This type of volcano towers over all other volcanoes. Shield volcanoes spread lava in many directions. The lava builds large, gentle slopes and even entire islands. Composite volcanoes are shorter than shield volcanoes. But they pack a punch! Layers of lava ash, and stone trap gases. The pressure builds up over time until the gases are released. The volcano erupts violently, just like a shaken soda can! Cinder cone volcanoes toss lava from their single opening or vent. They grow quickly, forming in a few months or years. However, these volcanoes are small compared to massive shield volcanoes.

Hawaiian Hot Spot Sometimes magma from deep below Earth's surface forms large pools closer to the surface than normal. These pools of magma are called hot spots. Earth's crust is made up of huge sheets of rock called plates. The Hawaiian Islands are in the middle of a plate that is slowly moving over a hot spot. As the plate moved over the hot spot, volcanoes formed. Each time lava rose above sea level, an island was born. For this reason, Hawaii is a chain of islands. The plate keeps moving over the hot spot. Now the hot magma is feeding Kilauea and causing the volcano to grow. The Big Island is getting bigger!

A Volcano Is Born Kilauea first erupted 100,000 years ago. That may seem like a long time ago, but it is the blink of an eye for a volcano. Kohala is the oldest volcano on the Big Island. It is more than one million years old! Volcanoes on other Hawaiian islands are older still. Kilauea is an active volcano. Lava flows up through vents and comes out of craters. The most recent eruption of Kilauea began in 1983. Lava oozed out of a crater called Puu Oo (PU-u OH-oh) for several decades! This is one of the longest nonstop eruptions ever recorded.

Lots of Lava A lava fountain occurs when the pressure inside the volcano forces lava out through a vent in the rock. The lava from a fountain, called aa (AH-ah), sprays upward and then quickly flows downhill. As it flows, the top layer cools off and breaks into chunks. These chunks get covered with more lava. In 1983, aa lava from Puu Oo reached a group of houses located 6 kilometers (3.7 mi.) from the vent in only thirteen hours. Kilauea erupted from a new vent in 1986. This vent created a lava pond. The lava leaving this pond formed a roof of rock that created a lava tube. Lava flowed slowly through the underground tube. This type of lava is called pahoehoe (puh-HO-ee-HO-ee).