Volcanoes W5L2

Question 1

Volcano shape is influences by

Answer 1

magma viscosity (silica content)
explosivity of eruption
frequency of eruption

Question 2

Shield volcanoes

Answer 2

succesions of large volume basalt flows
assosciated with loe explosvity, effusive eruptions
low angle of slope and low relief (can be very high)

Question 3

Volcanic Fissures

Answer 3

usually assosciated with basaltic volcanism

Fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity.

Question 4

Stratovolcanoes or composite volcanoes

Answer 4

!associated!with!explosive!erup>ons!
•!built!up!of!layers!of!ash!and!lava!!
•!typically!erupt!volumes!of!1!km3!in!a!big!erup>on!

Question 5

epicontinental calderas

Answer 5

supervolcanoes
when caldera collapses, larges volcanic structures formed
subsidence rather than mountains
high frequency, highly explosive

Question 6

small scale volcanic structures

Answer 6

monogenetic- erupt once

usually assosciated with larger volcanic fields

Question 7

Maars and Tuff rings

Answer 7

assosciated with diatremes
monogenetic events
leave very little geoogical evidence
usually infilled by lakes

Question 8

style of eruption classified by

Answer 8

explosivity

relative amounts of lava or ash

Question 9

eruptive style directly related to

Answer 9

viscosity and volatile conten

Question 10

the more viscous and volatile rich the magma is

Answer 10

the more liekly it is to errupt explosivelc

Question 11

Hawaiian Eruptions

Answer 11

typical of basaltic shield volanoes
mild, effusive eruptions
no major threat to human life
erupt regulary

Question 12

hawaiian eruptions characterised by

Answer 12

fire fountains
lava flows
negligible pyroclastic material
eex. hawaiianand icelandic volcanoes

Question 13

Strombolian Eruptions

Answer 13

assosciatede with viscous basaltic magmas
eruptions columns up to 1km high
abundant scoria ejection
alva flows

Question 14

Vulcanian Eruptions

Answer 14

small magnitude pyroclastic eruptions
andesitic type magmas (moderate viscosity) 
eruption 10-20 km
often throat clearing eruptions
small/ medium sized stratovolcanoes

Question 15

Vesuvian (Sub Plinian eruptions)

Answer 15

explosive, pyroclastic eruptions
large amounts of ash elejcted
eruption columns 30 km sustain
assosciated with andesitic rhyolitic lava

Question 16

Plinian Eruptions

Answer 16

rare events
45km high, sustained
20km tephra eruplted large amounts of pumice
ash flows
generally assosciated with high silica magmas

Question 17

Hydrovolcanic Eruptions

Answer 17

Steam assisted , phreatic

Question 18

Surtseyan activity

Answer 18

basaltic eruptions on seamounts close to surface
new islands created
large maounts of scoria ejected
steam plumes

Question 19

Ultraplinian Eruptions

Answer 19

incredibly violent ith dispersal of ash over huge areas