volcanoes Flashcards
what do you call a rupture in the crust that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface?
volcano
what is the lithosphere?
The layer of the earth which contains the brittle crust and the upper mantle
what is magma?
a mixture of molten and semi-molten rock found under the surface
what type of magma is low in silica and what is its silica content?
basaltic + 45-55%
it describes the thickness and stickiness of a fluid
viscosity
what does it mean if something has a high viscosity?
it means it is thick and sticky; something akin to honey
The layer of earth that lies below the lithosphere and is about 80-200km below the surface
asthenosphere
what are pyroclastic materials
solid fragments of lava, rock, glass, and ash ejected from a volcano
where is magma stored?
magma chamber
what is lava?
magma when it reaches the earth
its high viscosity magma caused it to form a tall, steep, and conical shape
stratovolcano
what is a divergent plate boundary?
when two plates diverge from each other
what do you call it when two plates converge together?
convergent!!!!
what is ash?
the smallest type of tephra
what do you call the largest type of tephra?
blocks
peanits??
yes!!!!
this type of magma is usually 1000-1200ºC in temperature and therefore is effusive
what type of rock does it form into?
basaltic
list the 3 factors affecting viscosity
- temperature
- composition
- dissolved gas content
this type of magma has 55-65% silica and is around 800-1000ºC in temperature
therefore, it also has a moderate viscosity, allowing it to be either effusive or explosive
andesitic
- 650-800ºC in temperature, making it high viscosity and makes explosive eruptions
its silica content is 65-75%
rhyolitic
what is a conduit
a passageway for magma to travel to the earth’s surface
what do you call the highest peak of a volcano?
summit
what is a crater?
the funnel-shaped opening at the top of the volcano that surrounds the vent
what do you call the part of the volcano that collapsed into itself?
caldera
what is a vent?
the opening through which magma, gases, and volcanic ash are ejected
what do you call the degree/slant of a volcano?
slope
what are shield volcanoes?
a slightly dome-shaped, short volcano formed usually from divergent plate boundaries and has highly fluid, effusive explosions
what do you call a small, steep volcano with short lived, small, explosive eruptions
hint: when it cools, it makes a material called cinder
cinder cone
what type of eruption has no magma involved?
phreatic / hydrothermal
what type of eruption has high viscosity magma (andesitic, rhyolitic), which traps gases making for a violent release of gases and magma
explosive
what if not explosive?!???!?
effusive!!!
what eruption occurs due to the contact between magma and water which then causes large columns of ash and sideway emission of pyroclastics
phreatomagmatic
what is the most powerful eruption type?
plinian
what is a vulcanian eruption?
an explosive, highly viscous eruption caused by trapped gases in the magma
what is a strombolian eruption?
periodic, weak and silly eruption with low viscosity (can make lava fountains) and has small, frequent outbursts
what do you call the 2nd smallest tephra that is about the size of a walnut?
lapilli
what do you call rounded fragments of cooled magma?
lava rock
what is a pumice?
a lightweight, silly little cooled piece of lava formed during an explosive eruption
