Volcanoes (and everything else) Flashcards
(39 cards)
what causes magma to rise to the earth’s surface?
magma is hot and has less density than its surroundings so it rises (convection current) + pressure
how does rising magma and flowing lava create underwater pillow lava?
an underwater volcano erupts and lava falls into the ocean, cools and traps gas
how does rising magma and flowing lava create volcanic islands?
over time, on the seafloor over a hot spot, the buildup of cooled magma that erupts underwater can create volcanic islands
how does rising magma and flowing lava create bulges in the earth’s surface
cool viscous magma under the earth’s surface rises and pushes upwards on the overlying rock
is slow-moving lava or runny lava more viscous? what’s another liquid that’s very viscous?
slow moving lava is more viscous than runny lava.
corn syrup is very viscous.
how does a composite volcano form?
it forms from alternating eruptions of very viscous lava and ash.
ex. mt st helens, mt fuji
how do cinder cone volcanoes form?
cinder accumulates around vent of volcano
ex. sunset crater
how do shield volcanoes form
fissures and hotspots produce low viscosity runny lava that spreads out to form a wide, broadly sloping volcano.
ex. the hawaiian islands, iceland
how does the heat content of a substance affect the ways it flows?
heated substances are faster since they have lower viscosity and cooler substances are slower because they have high viscosity.
heat decreases viscosity.
what are some of the challenges scientists face in deciding whether or not to issue an alert when they are monitoring potentially volcano
- possibility of no eruption
- unsure timing/unpredictable
- they have to be correct the first time or they’ll lose credibility
what are the constructive effects of volcanic eruptions
- renewal
- creates new land
- new minerals introduced to environment
- great view
name the destructive effects of volcanic eruptions
- destroyed property
- smothers crops
- coats peoples’ lungs
- fatalities
- decrease atmospheric temperature
which would be carried farther into the atmosphere: 2 mm ash or 64 mm lava bombs? explain why
2 mm ash, because finer and lighter ash will go higher up into the atmosphere and will be carried by the wind
how can a volcanic eruption affect weather conditions locally and globally
ash covers sunlight, changing temperature around the world
what is a vortex and what causes it to form
a vortex is the circulation of liquids or gases around a central axis
the uneven heating of the earth’s surfaces and earth’s rotation forms vortexes
how does air above a heated surface move
air will move up as it has less density and gains thermal energy
how does air above a cold surface move
air moves down as it has more density and transfers energy to the surface
what happens when hot air meets cold air
- convection current occurs
- boundary
- weather front
- clouds
- precipitation
how do hurricanes form
- warm tropical water
- low air pressure
- earth’s rotation
what role does the sun play in the weather on the earth
sun supplies heat energy and moves water and air, creating weather
what is a convection current
warm liquids/gases rise because its less dense. as it rises it begins to cool and sink, circulating flow due to temperature
in what direction is the weather moving across usa? how can this help meteorologists?
weather moves from west to east. this can help meteorologists predict the weather easily
how do some deep ocean currents form?
uneven heating of water and salinity of water
how do winds affect ocean water
wind creates surface currents that move water and creates upwelling
