What are volcanoes? 4/26/17 volcano= a weak spot in the crust,

formed by plate tectonics, that erupts out magma/lava…Mt w/ hole in it filled with liquid rock

magma=liquid rock INSIDE the volcano

lava=liquid rock OUTSIDE the volcano

Ancient Greeks thought volcanoes were the home of Hephaestus, God of Fire & Forge…Roman God Vulcan which gives the word “volcano”

Ancient Polynesians/Hawaiians believed in Pele, goddess of the volcano

Form on divergent & convergent PT boundaries

Most explosive land form on Earth Volcanoes keep building up by

erupting Can be extinct, never erupting again

& be just a cone shaped mtn.

Magma chamber is a “hot bubbling furnace”

Created the atmosphere by releasing CO2

Create while destroying Beautiful, yet deadly & dangerous…

Nature’s fireworks show! Crater is created in the first eruption

when the top is blown off the mtn. PT divergent & subduction zones

create a weakness/crack in the crust where magma can escape

Located on all continents except Australia

Ring of Fire=lg volcanic belt outlining the Pacific Ocean; most volcanoes are here

Island arc= arc of volcanoes formed along a deep ocean trench @ OvsO boundary: Japan

Volcanic arc= arc of volcanoes formed along a CvsO boundary: Andes Mts in South America &

Cascade Range of North America (Oregon & Washington)

Hot spot volcanoes=volcano found in the middle of a plate rather than on a boundary: Hawaii & Yellowstone National Park (Wyoming/Montana)

What does a volcano look like on the inside? 5/3/17 (structure)

ALL volcanoes have the SAME internal structure

1) crater= bowl shaped/indent area surrounding the vent @ the top of the volcano…where an eruption “starts”

2) pipe= long tube in the ground that connects the magma chamber to the surface/vent… “the straw”

3) vent= opening where magma comes out & turns into lava

4) magma chamber= pocket/pool of magma from the mantle @ the bottom of the volcano

5) side vent= vent on the side of the volcano

6) lava flow= flow of lava going down the volcanic mtn

Why do volcanoes erupt and what happens during an eruption? 5/9/17

force of expanding gases pushes the magma from the chamber, through the pipe, out the vent

gases are dissolved in magma gases expand b/c pressure from the

earth decreases as magma rises

Silica (SiO2) content of magma creates two types of eruption:1) quiet eruptions = low silica

magma; thin, runny, quiet oozing*pahoehoe lava= HOT!! very runny & thin consistency/ low viscosity *aa lava= hot! more viscous than pahoehoe*lava flows, lava rivers, lava drips into the ocean, lava burps*Hawaiian volcanoes * “Blub-Blub”

2) explosive eruptions= high silica magma; thick, sticky, clogs vent like a cork!* pyroclastic flow= mix of poisonous gases, ash, cinders & bombs hurtling down the volcano side HOTTTT!!!!!* forms obsidian (volcanic glass) & pumice*BOOMER!!!!

What are the different forms of volcanic mountain? 5/16/17

(glued in stuff)

three stages of volcanic activity:-active=is erupting right now-dormant= “sleeping”-may erupt in the future-extinct= will never erupt again…DEAD!

What other landforms are created by volcanic activity? 5/18/17

caldera= a large crater formed by a large eruption when the magma chamber empties & collapses

volcanic soil= broken down ash adds potassium & phosphorous to the soil making it ++++fertile

dike=magma that hardened across layers of rock vertically or diagonally-II

sill= magma that hardened between layers of rock horizontally-II

volcanic neck=magma hardened in the pipe (Ship rock)-II

batholith=LARGE dike/sill formation (Sierra Nevada Mtns)-II

geysers=hot column of water and steam shooting in to the air (Old Faithful)

hot spring=natural pools of earth heated water

geothermal activity= “Earth heated”…hot springs & geysers & other stuff that happens in volcanic areas

igneous intrusion (II)= when magma hardens underground “intruding” on the other rock layers

What did I learn from the video: Eyewitness Volcano 5/12/17