Volcanoes These notes go on p. 11 of your inb !!!

VOLCANOESTHESE NOTES GO ON P. 11 OF YOUR INB!!!

VOLCANIC SETTINGS (PLATE BOUNDARIES)CONTINENTAL

divergence

Ocean-Continent

ConvergenceOcean

DivergenceOcean-Ocean Convergence

Major Volcanoes Around the World

“RING OF FIRE”:Area surrounding the pacific plate where the most volcanoes &

earthquakes occur

PLATE TECTONICS AND MAGMA GENERATION

PARAMETERS OF VOLCANISM Viscosity Chemistry of Magma Gases within the magma Water content of magma

VOLCANIC ACTIVITY Active Volcanoes: recent eruptions,

active magma source Mt. Etna, Italy

Dormant Volcanoes: no recent eruptions, but still has an active source of magma Mt. St. Helens, USA

Extinct Volcanoes: no recent eruptions, no source of magma Northwestern Hawaiian Islands

TERMS TO KNOW: Viscosity- the resistance of lava to flow

• Ex: The more viscous the lava, the thicker and stickier the material & the harder it is to flow (honey vs. water)

• depends on the amount of silica

•the type of crust being melted determines the amount of silica!

TERMS TO KNOW: Caldera: large crater shaped basin that forms

when the top of a volcano collapses

FORMATION OF CRATER LAKE

TERMS TO KNOW: Hot Spot- random

upwelling of magma NOT associated with convection in the mantle create a special type of

volcanism not associated with plate boundaries

Ex: Hawaii, Yellowstone & Iceland

Kaui

Molokai

Hawaii

Oahu

LanaiMaui

TECTONIC SETTINGS AND VOLCANIC ACTIVITY

3 TYPES OF VOLCANIC CONES:1. Cinder Cones: explosive eruptions, small but steep slopes, pyroclastics

Cinder Cone

VOLCANO TYPES

3 TYPES OF VOLCANIC CONES:2. Shield: non-explosive eruptions, fluid basaltic lava, gentle broad slopes

Volcano Types

3 TYPES OF VOLCANIC CONES:3. Composite Cones/Stratovolcanoes: alternating between lava and pyroclastics, explosive and non-explosive eruptions, very steep/tall

VOLCANO TYPES

TYPE OF ERUPTIONS Depends on type of crust melted Oceanic Crust- quiet, effusive eruptions

Volcano type- shield, fissure, mid-ocean ridges Magma type- mafic & ultramafic

Continental Crust or ocean/cont. mixed- explosive eruptions, pyroclastic flows, calderas, aerial bombs Volcano type- stratovolcanoes & cinder cones Magma type- felsic

BASALTIC LAVA TYPES Pillow Basalts (underwater)http://www.youtube.com/watch?v=DdIUuUY0L9c

AA lava- jagged lava

Pahoehoe- ropey, smooth lava

C

PYROCLASTIC FLOWS

searing superheated gas and volcanic ash & dust; very fast

Also called “Nuee Ardente”

http://www.youtube.com/watch?v=-H_HZVY1tT4Mt. St. Helens Eruption

http://www.youtube.com/watch?v=WxlRpuTed6gPyroclastic Flow

C

DEBRIS AVALANCHE AND ERUPTION OF MOUNT ST. HELENS, WASHINGTON

VOLCANO CARICATURES Draw an exaggerated, cartoon form of a

type of volcano Cinder Shield (Dome) Composite

Write a 5-6 sentence summary about it’s “personality.”Must include type of eruption, type of lava,

size/shape, and location.