# Shared Flashcard Set

## Details

Volcanoes Earthquakes Tsunami
test review cards
33
Geology
04/10/2007

Term
 three stresses
Definition
 compressiontensionfolding
Term
 compression
Definition
 two tectonic plates collide
Term
 tension
Definition
 stress that occurs whebn forces act to to stretch an object
Term
 two kinds of seismic waves
Definition
 P WavesS Waves
Term
 seismic wave
Definition
 a wave of energy that travels throught the earth, away from an earthquake
Term
 P Wave
Definition
 a sismic wave that causes particles of rock to move in a back and forth direction Primary Wave (the first waves to be detected)travel through liquid, solid,and gas
Term
 S Wave
Definition
 a seismic wave that causes particles of rock to move in a side-to-side directionsecondary waves slower than P waves and stretch the rock sideways, cannot travel through liquid
Term
 studying siesmic waves helps scientists
Definition
 measure earthquake size and intensityfind an earthquakes' epicenter
Term
 How to locate an earthquake's epicenter once the distance from the epicenter of the quake to each of three siesmographic retorting stations is known
Definition
 1. use the S-P time method2. collect seismograms from 3 diff locations3.place them on a time distance chart4. draw a circle around a siesmograph station with the radius = distance from the station to the epicenter5.draw a second circle around another station6. the circles will overlap in 2 spots7.draw the third circle and where all 3 overlap is the epicenter
Term
 Earthquake damage is measured on two scales
Definition
 Richter ScaleMercalli Scale
Term
 Mercalli Scale
Definition
 Measures the intensity of earthquakes from I(some only felt at the epicenter) to XI (total destruction)
Term
 Richter Scale
Definition
 measures magnitude from 2 ( only detected only by a seismograph )to 7 ( can cause great, widespread damage)Created in the 1930's by Charles Richter to compare earthquakes by measureing ground motion recorded by siesmograms at seismograph stations
Term
 Home preparation for an earthquake
Definition
 place heavy objects on low shelvesdetermine a safe place inside the housedetermine a safe place outside the housedetermine where to meet afterwardsHave stored: water, food, fire extinguisher, flashlight, portable radio, medicine,and first aid kit
Term
 What to do during a quake
Definition
 Inside:get under a table or desk in center of roomOutside: away from building, powerlines, and trees, lay flat and cover head. In a car, stop car and stay inside
Term
 Fastest seismic wave
Definition
 Primary Wave
Term
 vent
Definition
 opening in Earth's crust through which magma is released
Term
 caldera
Definition
 magma chamber below a volcano partially empties and causes the ground above to sink
Term
 crater
Definition
 funnel shaped pit near the top of the central vent of a volcano
Term
 magma
Definition
 molten rock found deep within the Earth is called
Term
 hot spot
Definition
 area with active volcanoesfar from tectonic plate boundry
Term
 lava plateau
Definition
 wide flat landform that results from repeated nonexplosive eruptions of lava that spread over a large area
Term
 rift zone
Definition
 area of deep cracks that firns between two tectonic plates that are pulling away from each other
Term
 cinder cone
Definition
 A volcano created from moderately explosive eruptions of pyroclastic material. They are usually small and usually erupt for a short time
Term
 80% of volcanoes form
Definition
 where tectonic plates collide along plate boundries
Term
 mantle plumes
Definition
 some scientists believe that these are columns of rising magma that may cause the hot spots
Term
 pyoclastic material
Definition
 forms when 1.magma explodes from a volcano and solidifies in the air2.powerful eruptions shallter exising rock these can be as big as a house!3. some materials are: volcanic bombs, volcanic blocks, lapilli and volcanic ash
Term
 silica rich magma
Definition
 is thick and stiffflows slowlyhardens the volcano's vents
Term
 magma with less silica
Definition
 is fluid and runnyvolcano has less explosions
Term
 predicting an eruption of a volcano
Definition
 changes in:volcanic gasesinternal temperatureslope of volcano
Term
 aa lava
Definition
 names for its jagged surface that hurtspours out quickly and makes brittle crust as molten lava flows under it
Term
 pillow lava
Definition
 lava under water makes round lumps in the shape of a pillow
Term
 blocky lava
Definition
 coolstiffnot travel faroozes makes jumbles heaps of sharp edged chunks
Term
 exploding volcanoes
Definition
 magma with high silica contentsilica rich magma blocks ventsgas is trappedexplodes
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