Lecture 6 - Volcanoes/Volcanic Eruptions Flashcards
(52 cards)
What was one of the largest volcanic eruptions in recorded history?
Toba
What is the highest volcano
Mauna Loa
Global distribution of igneous activity is not random. Most active volcanoes are located within or near ________
Ocean basins
There are 4 major types of volcanoes, classified according to
their shape, composition of magma and style of eruptions
What are the 3 factors determining the “violence” of a volcanic eruption
Composition of magma
Temperature of magma
Dissolved fases in magma
Felsic rocks (granitic, rhyolitic) are sillica rich which will create what type of magma
very viscous
Mafic rocks (basaltic) are silica poor, which will create
Much more fluid-like magma
low temp = ____ viscosity
high
low gas = _____
viscosity
if lava is low viscosity, them bubbles can escape. What type of volcano will emerge?
non=explosive eruption (effusive
if lava is high viscosity, then pressure inside lava buils up. What type of volcano will emerge?
Explosive eruption
what type of lava comes out of an effusive eruption and resembles a twisted/ropey texture
pahoehoe lava
what type of lava comes out of an effusive eruption and is rough, jagged blocky texture
AA lava
What type of lava comes out of an effusive eruption and is found underwater
pillow lava
What is a lava dome/volcanic dome
Bulbous mass of congealed lava. Most are associated with explosive eruptions of gas-poor magma
What types of pyroclastic (fire) debris come out of explosive eruption?
tephra: ash and dust cinders pumice lapilli blocks bombs
What is tephra?
ash and dust (fine glassy fragments)
What is cinders
pea-size material
What is pumice
porous rock from “frothy lava”
What is lapilli
walnut size material
What particles are larger than lapilli
blocks and bombs
what are blocks
hardened or cooled lava (meters)
what are bombs
ejected as hot lava; teardrop shape
What is an eruption column
cloud of gas and tephra that can reach 45 km high
