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The continent they think the continets were once all a part of?


Who had the continental drift idea in 1915?

Alfred Wegner

What evidence was found proving that the continetal drift happened?

fossils rocks and mountain ranges

Coastline evidence?

the shape of the coastlines were evidence

How was the ocean depth determined?

technology using sound waves

Best fossil evidence of animals?

land animals

How were the fossils found to be evidence?

It was believed the living things fossils were distributed

What could Wegner not explain?

He could not explain how they split apart

How did Wegner say htey split apart?

He said the seafloor seperated

Mid ocean ridge

system of mountain ranges on seafloor seperated by valleys

Who provided the idea of mid ocean ridge?


What did Hess think the magma did?

He thought the magma is buoyant and rises upward through the cracks in the crust

rift valley

long narrow depression

What was the evidence on the seafloor?

rocks and sediments

What happened when the rocks hardened?

magnetic property spread along the floor

What was the plate tectonics theroy?

Earths surface is made of slabs of rigid rock that move over Earths upper mantle

What makes up the bottom part of the plate?

Solid layer of mantle

What makes up the top mantle?

Oceanic crust

Convergent plat boundaries



where the plates dive underneath eachother


moving apart

transform plate boundary

moving horizontallly


collective movement of ensembles of molecules within fluids (i.e. liquids, gases) and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids.

Convective heat transfer is one of the major modes of heat transfer and convection is also a major mode of mass transfer. Convective heat and mass transfer take place through both diffusion

ridge push

proposed mechanism for plate motion in plate tectonics. Because mid-ocean ridges lie at a higher elevation than the rest of the ocean floor,

slab pull

tectonic plate motion due to higher densities

most popular gas thats erupted

water vapor

runny lavas viscosity

low viscosity

cinder cone volcanoes

small, short eruptions

shield volcanoes

broad falt structures composed of layers of lava low viscosity flow

composite volcanoes

large, steep shield, layers of lava and ash

shield volcano

forms above hot spots

earths outer core



crust and uppermost mantle combined


tectonic plates move on top of the upper mantle

what happens when pressure increases to the rock?

melting point of rock increases


liquid stored inside the earth

what happens when magma is forced upward?

causes a split in the rock

what happens when magma reaches the surface?

causes a volcano

convergent boundaries

plates combine

hot spots

areas of volcanic activity where magma moves towards earths surface


measure of fluid resistance to flow

low viscosity

flow more slowly

chemical composition

affects viscosity


common in magma SiO2

pyroclastic material

solid material that erupts from a volcano

small particles

volcanic ash

large particles

volcanic cinder


sudden movement or vibration of the ground that occurs when rocks slip and slide

where earthquakes occur

in tectonic plate boundaries

what percent occur along plate boundaries?

95 percent

what occurs when energy is realesed?


forces applied to rocks along plate boundaries cause


compression stress

object is squeezed or shortened

tension stress

stretched or lengthened

shear stress

different parts move in different directions

torsion stress

object is stressed

plastic deformation

material changes shape as a stress is applied


crack in earths crust

elastic rebound

sudden release of strain energy as rock moves along a fault


point of origin of a earthquake


directly above the focus

p waves

fastest travel through solids and liquids

s waves

slower only through solids

surface waves

only travel on the surface from side to side

richter scale

measures energy realesed during an earthquake , measures amplitude

mercalli scale

ranks earthquakes on intensity and amount of damage

damage is the greatest when

it is near the epicenter

what materials are the strongest

the ones that bend

what do seismic waves do?

help scientists investigate the earth

when waves chaneg speed they aslo can

change direction


change that causes a wave to bend and change direction


boundary between two layers of material that have different density

what are discontinuity identified by

seismic waves

shadow zones

areas on earths surface where no seismic waves are recorded

when do shadow zones occur?

shadow zones occur when s waves cant travel through earths outer core

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