September 18

September 18 - Shield Volcanoes Broad very gently sloping...

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Shield Volcanoes: Broad, very gently sloping. ** On top montacae- looks over mauna loa Montacae (very tall- 14,000 ft tall) on top of it are a bunch of cinder cones. Can have one type of volcanoes on top of eachother with another type. Mauna loa (Hawaii)- biggest volcano on earth (14,000 ft tall) but if you take it's height from below sea level to the top. as high as mt everest. Same height, 29,000 ft tall- subarial portion (stuff below and ontop of ocean) made up with basalt (runny stuff), not so much silica or gas. most of the volcano is made up with lava flows. the fluidity of the lava is part of the reason this volcano is very gently sloping. There are also gentle because the erupting rates are high. creates a low angle to the volcano. Mauna loa erupts periodically. Shield volcanoes are mainly made up of balsaltic lava flows. Occasionally shield volcanoes have explosive eruptions. this happens when in the crater, there's an active lava lake. If the lava lake drops fast, drops below water table, as level of lava lake goes down, the walls of the crater collapses and forms a ruble file. Then fall infiltrates in collapsed area, the water with the hot rock, magma, explosive eruptions . - Exception Read Volcano reading On other planets there are also shield volcanoes. On Mars- Olympus mons.- 500-600 km in diameter. - Shield volcano. Scale is completely different between earth and mars. Kila wea- still erupting today - in Hawaii. Hawaii is made up with a series of shield volcanoes (4-5) Is the shield volcano, olympus mons active? No. We haven't seen any evidence of activity. Open question to when it last erupted. (long time ago or relatively recent- geologically recept= couple million years ago) Strato Volcano - associated with subduction zones. Plate tectonics -Subduction zone= Where oceanic goes under a continental plate. or oceanic goes under oceanic. as plate goes down back into mantel, it heats up and magma is produced and volcanoes occur along subduction zones. oceanic plate is diving down into the mantel, getting subduction down into the
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This note was uploaded on 09/24/2010 for the course ARTS NDIS235 taught by Professor Schwarts during the Fall '09 term at McGill.

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September 18 - Shield Volcanoes Broad very gently sloping...

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