Volcanoes

explosive eruption

felsic magma under pressure; cooler temp

effusive eruption

mafic magma, lower pressure, higher temperature

A'a lava flow

rubbly, slow

Pahoe hoe lava

smooth, ropey, taffy

how lava cools

from the outside in

silicas affect on lava

makes lava not flow good; the more of it the less likely the lava is gonna flow

Pyroclastic's

rock material and lava violently ejected from the volcano

pyroclastic flow

hot gases and particles of rock flying through the air; stays close to the ground

pyroclastic fall

pyroclastic material is ejected into the air and falls back to the ground; can go over large distances

pyroclastic deposits

Accumulations of fragmental volcanic debris; ash, cinders, bombs

cinders

cunks of rocky lava

visocity

resistance to flow

felsic magma is generated at

subduction zones

Magma Properties

gas content, visocsity

gas content causes

explosively

influences of gas content

amount of gas on magma type, sub zones

water vapor is more soluble in

felsic magma

low viscosity

freely flowing

high viscosity

slow

influences on viscosity

molecular bonds

size and shape of a volcano are determined by

lava type

steep sided volcanoes are likely made of

felsic lava

cinder cone volcanoe

- small magma chamber
- can have a field of them
- made of pyroclastic material not lava

shield volcanoes

made of mafic lava, Hawaii, can erupt in many different directions in the chamber

caldera

the sunken collapsed part of volcano where lava comes out from ; the crater

Stratovolcano

- what we think of a volcano
- explosive eruptions
-landslides are very common
- steep sided
- have different stratification from layers that make it up

stratification layers

felsic lava flow and pyroclastic material

dome complex

very felsic, don't erupt explosively, not very common

caldera formation

- after a volcano erupts the magma chamber is depleted
- took energy to erupt now have void where there is no magma so the broken rocks collapse down b/c no underlying support

which type of lava would be runny(low viscosity)

mafic

which type of lava would have high viscosity

felsic

Which type of lava will let gasses escape easily

mafic

rhyolite igneous rock

felsic, more explosive, pyroclastic deposits, low temp

basalt rock

mafic, less explozive, lava flows, higher temp

more felsic means more

explosive and viscous

volcanic hazards

Lava flows, Lahars, Pyroclastic flows, Ash falls, Volcanic landslides, explosive blast

Lava flow

slow moving, cools from outside in

Pyroclastic flow

high density mixture of hot,driy rock fragments and gases, generate quickly, very destructive

Ash falls

jaged fragments produced from explosive volcanic eruptions, cause haze

lahars

eruption mixed with water, water sitting on top of a volcano, muddy river

how to predict if a volcano will erupt

- earthquake activity
- changes in heat flow
- changes in shape
- increase gas and steam

weathering

The breaking down of rocks and other materials on the Earth's surface.

erosion

entrainment, rocks being picked up and moved

production of sedimentary rocks

weathering, erosion, transport, deposition, lithification

physical weathering

taking a solid rock/mineral and making them into smaller pieces

freezethaw

water continuously seeps into rocks where it freezes and expands

salt wedging

salt seeps into rocks cracks and expands and contracts

root wedging

the roots of a plant (typically a tree) wedge into a crack in a rock and, as the plant growns, splits the rock.

sand blasting

How wind mechanically weathers rock

How physical weathering increases chemical weathering

more broken up rock increases SA which increases chances

chemical weathering

-takes place at the surface or near surface,
-need oxygen and water

Acidic water

helps speed dissolution process along

minerals with ionic bonds

makes them nonresistant to chemical weathering

Silcate Minerals

very resistant to chemical weathering

minerals with iron

weak resistants to chemical weathering

Felsic and weathering

more resistant to weathering

influences on chemical weathering

climate, type of rock, time of exposure

immature

non resistant minerals

mature

resistant minerals