Volcanoes

Title – Volcanoes p.1 1/3/17 A Volcano is… A location where magma (molten rock beneath the earth) reaches the earth’s surface through a vent or crack. This magma can be released as Lava, Gases, Pyroclastics (fragments of rock).

Parts of a Volcano Magma chamber: contains magma (molten rock) deep w/in the Earth's crust. Vents: smaller openings on the surface through which magma leaves volcano. Crater: basin from which magma erupts as lava, gases & pyroclastics Pipe: tube that connects magma chamber to Earth’s surface

You will do this after notes “p.2” 1/3/17 Parts of a Volcano Crater Lava Flow Magma Chamber Pipe Vent You will do this after notes

Viscosity… Property of fluids, has to do with friction, think of it as the state of being thick & sticky (honey vs. water) Magma low silica =>lower viscosity (thin and runny). Magma high silica =>higher viscosity (thick and slow moving). high low

Magma/Lava contents… Basaltic magma -- SiO2 45-55 wt%, Fe, Mg, Ca K, Na. low silicate content low viscosity (thin & runny), gases escape easily (not trapped), non-explosive eruptions (most likely shield cone volcanoes)

Magma/Lava contents… Andesitic magma -- SiO2 55-65 wt%, intermediate in Fe, Mg, Ca, Na, K. a medium level of silica content intermediate viscosity, intermediate explosiveness.

Magma/Lava contents… Rhyolitic magma -- SiO2 65-75%, Fe, Mg, Ca K, Na. high silica content high viscosity (thick & slow moving), gases cannot escape easily (they get trapped), very explosive eruptions (most likely cinder cone volcanoes).

Magma/Lava contents… Dissolved Gases As dissolved gases explosiveness. Water Vapor {H2O(g)} is the most common dissolved gas in magma.

Explosive vs. Non-Explosive Essentially is due to viscosity of lava The more viscous, the more explosive Amount of Silica Temperature (colder) % of Water Vapor

Parts of a Volcano Cut out & attach base to “p.2” 1/3/17 Parts of a Volcano FLAP Cut out & attach base to “p.2” Place definitions on appropriate lines of “base” Place labels with definitions Place flap over base, attach at top, so that it can be lifted. Place remaining definition & label on flap. * You may color, this should be completed before next class! BASE

Today…. Structure & Parts of Volcano You should be able to label diagram Structure & Parts of Volcano Crater, Magma chamber, Pipe, Tube, Vent Composition of Lava Magma, gases, & pyroclastics 3 Types of Magma/Lava Basaltic Andesite Rhyolite You should be able to list these items, most common gas? You should be able to tell relative amounts of SiO2 in each type, & what type of eruption

Wednesday 1/4 Finish Volcano diagram ASAP Smithsonian/USGS Weekly Volcanic Report http://volcano.si.edu/reports_weekly.cfm Volcano Discovery https://www.volcanodiscovery.com/volcanoes.html Volcano Webcams http://webcams.volcanodiscovery.com/ “Yellowstone super volcano could erupt in 2016 and wipe out the earth” start @ https://www.youtube.com/watch?v=lwtX9ffJaco