Eos Lecture 10

Front 1

Caldera

Back 1

a large circular depression that forms after an eruption when the volcano collapses into the drained magma chamber below

Front 2

Volcanic Explosivity Index (VEI)

Back 2

- volume of erupted material
- height of the eruption column
- scale is between 1 and 8 - most eruptions 1 to 5
Step 1: Magma Chamber causes doming
Step 2: Pyroclastic eruption
Step 3: Dome collapse into emptied portion of magma chamber
Step 4: Extrusion of rhyolite flows into caldera

Front 3

Ignimbrite

Back 3

- Welded Tuff
- hot pieces of pumice, ash and cinders get “welded” together in a hot pyroclastic flow

Front 4

Banded Rhyolite

Back 4

extruded after the pyroclastic debris in the form of flows (the dark bands are volcanic glass)

Front 5

Basalt

Back 5

dark mafic extrusive igneous rock

Front 6

Fumarole

Back 6

steam and gas vent

Front 7

Mudpot

Back 7

Thick bubbling mass of water and mud

Front 8

Hot Springs

Back 8

Hot water that flows onto the surface through an open conduit

Front 9

Spouter

Back 9

Ejects hot water in a column much like a broken fire hydrant

Front 10

Geyser

Back 10

Ejects water and steam into a high-fountain like column

Front 11

Sinter

Back 11

- Geyserite
- Deposits of silica brought up by the hot waters

Front 12

Travertine

Back 12

Deposits of calcium carbonate brought up by the hot waters