Volcanoes Flashcards
where are volcanoes located?
located in long chains along destructive and constructive plate boundaries
what are examples of where volcanoes are located in chains?
the mid-atlantic ridge
pacific ring of fire
what is an active volcano?
a volcano which has erupted recently
what is a dormant volcano?
a volcano which has erupted in the last 2000 years but not recently
what is an extinct volcano?
a volcano which is unlikely to ever erupt again
what is lava?
magma above the surface
what is magma?
molten rock underneath the surface
what is viscosity?
the thickness of the lava
what is silica?
the more silica the more vicous and resistant to flow
what is a caldera?
a cauldron like feature
formed by the collapse of land following a volcanic eruption
what is the main method of measurement of volcano?
volcanic explositivity index
a logarithmic scale running from 0-8. as they move up the scale they become less frequent
cinder/acid cone
- simplist form of volcano
- built from particles and blobs of lava
- gas exchanged violent eruptions
- steep sides with a bowl shape crate
- most are less than 100ft
- thick lava so can’t travel far
what are the 3 types of lava?
basaltic flows
andestic flows
rhyolites
what are the characteristics of basaltic flows?
- generally least viscous of lava flows
- tend to form thin laterally extensive flows
what are the characteristics of andestic flows?
- considerably more viscous
- thicker less extensive flows
