Haleakala Facts
|
Life Stages of Hawaiian Volcanoes
|
1- Submarine Stage
Gentle eruptions of fluid lava flows add layer upon layer to built a shield shape volcano deep on the ocean floor. This stage may last for about 500,000 years. (for example Loihi: 20 miles, 32 km, south of the island of Hawaii)
2- Emergent Stage
As the volcano emerges from the sea, steam explosions occur building a cone. When the debris piles high enough above erosive ocean waves, further eruptions take place on dry land. (no modern example)
3- Shield Building Stage
Frequent eruptions of fluid lava at the summit and along rift zones, weak ridges along the side of the volcano, rapidly add to the shield profile. A summit caldera, a large crater created by collapse, may form and then fill with lava and collapse again repeatedly as the volcano grows. (Kilauea and Mauna Loa. Island of Hawaii)
4- Giant Landslide Stage
As a volcano grows, it is unstable. Recent discoveries of landslide debris on the ocean floor around Hawaii suggest that up to one third of the above sea level portion of a Hawaiian volcano may suddenly collapse into the sea as the volcano grows. (Kilauea, Island of Hawaii)
5- Capping Stage
A steep-sided cap of lava covers the volcano. Capping stage lavas lava have a different chemical composition and may cause more explosive eruptions than the shield lavas. Time between the eruptions increases until they eventually stop. (Mauna Kea, island of Hawaii)
6- Erosional Stage
Streams and ice carve valleys and canyons. Ocean waves pound the shoreline producing sea cliffs. This erosion reduces the height of the volcano. Coral reefs are built by tiny marine animals which cannot survive while lava flows into the sea. (Kohala, island of Hawaii)
7- Renewed Volcanism Stage
After a quiet period several hundred thousand of several million years long, eruptions may begin again. Activity may be sporadic and explosive, and does not necessarily follow the old rift zones. (Haleakala, Maui)
8- Atoll Stage
Erosion wears the remaining land down to sea level. Coral reefs grow around the old volcano forming an atoll, a low island with a lagoon in the middle. Eventually the reef will die and be reclaimed by the sea. (Kure Atoll: located nearly 1500 miles, 2400 km, northwest of Maui)
|
|