Volcanoes and Earthquakes

the point beneath the earth's surface where the rocks break and move; origin of the earthquake

directly above the focus on land

L waves; arrives lastly; the slowest moving but the most damaging; travel in a circular motion

P waves; arrive first and travel through 3 phases of matter; longitudinal waves

S waves; arrive secondly and travel through solids only; travel in an S pattern

instrument that detects and measures seismic waves

sea floor earthquakes; can travel 700-800 km/hr and reach a height of 20 meters

hot liquid rock found underground in magma chambers

hot liquid rock outside the earth and comes to the surface through volcanoes

usually hot regions of earth's mantle where plumes of magma rise to the surface

violent eruptions of gas, ash, and other tephra, thousands of degrees, can move 200 km/hr

large crater

when the top around the vent becomes bowl shaped

the material thrown into the air during eruptions

a number that characterizes the relative size of an eathquake

a number describing the severity of an earthquake in terms of its effects on the surface and on humans and their structures

P waves travel through 3 phases of matter while S waves travel through only solids

An earthquakes is the shakes and trembling that results from the sudden movement in earth's crust; faulting causes earthquakes.

It's easier to dig to the mantle near a volcano

either violent or gentle

http://i1095.photobucket.com/albums/i479/lynn2426/cindercone.jpg

https://classconnection.s3.amazonaws.com/754/flashcards/1160754/png/shield_volcano1328637225626.png

http://www.enchantedlearning.com/subjects/volcano/gifs/volcanodiagram.GIF

steep sides; generally small; has violent eruption pattern

a mountain with broad, gently sloping sides; nearly a round base; formed by gentle eruptions and later after layer of lava accumulations

larger than cinder-cone but smaller than shield; made of alternating layers of cinders and lava; gently eruption first then explosive

Seismologists use the difference in arrival time between P and S waves to calculate the distance between the earthquake source and the recording instrument (seismograph).

at least 3