Volcanoes Flashcards
how are volcanoes formed?
when molten rock (magma) from the mantle bursts through a weakness n the earths curst
what is the red hot molten rock that is being realesed?
lava
what are the people called who study volcanoes?
vulcanologist
where does pressure build up in a volcanoe?
in the magma chamber
what comes out of the vents of a volcanoes ?
ash and steam
what happens when a volcanoes erupts?
lava flows from the vents and red hot fragments of rock, dust and ash, steam and other gases shoot out of the crator
what are the larger fragments of rock that are blown out of the crater called?
volcanic bombs or lava bombs
what are the features of lava?
runny or pasty like toothpaste
what happens if the lava is runny?
flood larges area and when cooled form large basalt plains
what can thick, pasty lava cause?
lava block the vents when it cools which build up magma
what happenes when the volcanoes pressure increases?
it starts to buldge and the top “blows up” which thrusts the rocks and send lava and gases high in the air
what are the types of volcanoes ?
lava dome, shield volcanoe, compostie volcanoe and cinder cone
what is the other name for composite volcanoe?
starto
what is the other name for cinder volcanoe?
scoria cone
what is pyroclastic flow?
fast moving current of hot gas, ask and rock/ lava bombs
how does pyroclastic flow travel?
hugs the ground, and downhill and sometimes spreads laterally
what does pyroclastic flow depend of?
the denisty of the current, the volcanic output rate or the gradient of the slope.
what can pyroclastic flow generate?
a lahar
how does pyroclastic flow generate a lahar?
from rain or melted water from glarciers or ash mixes
what is a lahar?
violent mud flow or debris that is composed of a slurry pyroclastic material, rocky debris and water
where does lahar tyipcally flow?
along river vallies
what are the two types of volcanoes?
active and extinct
what are the two types of active volcanoes?
domant and erupting
what are active volcanoes?
has at aleast ONE ERUPTION during the past 10, 000 years
what are extinct volacones?
had NO ERUPTION in the past 10, 000 years and is not likely to erupt
what are active erupting volanoes?
having an eruption
what is domant active volcanoes?
not erupting but will most likely erupt again
where are volcanoes found?
on the edges of tectonic plates
what is a volcanic hot spot?
an are where the mantle rises from the heat as a thermal plume deep in the earth
what are oceanic volcanoes?
move away from he hot spor, which then cools and subcide
what do oceanic volcanoes produce?
islands, atolls and sea mounts
what are examples of oceanic volcanoes?
Hawaii and Samoa
what are continetal volcanoes?
move away form hot spot, cool and subcide and become extinct
what are examples of contiental volcanoes?
western Victoria and Queensland
what kind of volcanoes do Australia have?
extinct volcanoes
what are examples of extinct volcanoes in Australia?
Mount Gambier and Mt Shank
who do Australia have less volcanic activty and earthquakes?
centre of the Indo Australia plate
