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84 Cards in this Set

  • Front
  • Back
What is the crust?
the outermost layer of the earth
What is the crust made of?
it is rigid and is made up of very thin solid rock
What is the thickness of the crust?
It varies little (5km-300km)
Where is the crust thinnest and thickest?
It is the thinnest under oceans and the thickest under mountains.
What are the three parts of the mantle?
the lithosphere, asthenosphere, and mesosphere
What is the lithosphere made of?
the crust and rigid layer
What is the lithosphere divided into?
tectonic plates
Why does the lithosphere float on the asthenosphere?
because it is less dense
What is the asthenosphere?
the soft layer that the lithosphere moces on (liquid hot magma)
What is the mesoshpere?
the main thickest layer of the mantle
What are the two parts of the core?
outer core and inner core
what is the outer core made of?
liquid nickel and iron
What is the inner core made of?
solid nickel and iron
Why is the inner core made of solid nickel and iron?
because of the pressure that is put on it
Why would it be thought that the continents are drifting?
because Alfred Wegener examined the continents and noticed that the coasts fit together
Why would it be thought that the continents are drifting?
because Alfred Wegener examined the continents and noticed that the coasts fit together
What is it called when the Earth was one single land mass
What are the two types of evidence there is for the drifting continents?
fossil evidence and rock evidence
What is the fossil evidence?
there are identical fossils in Africa and S. America
What is Glosspteris
a fossil found in S. Africa, Australia, India, and Antarctica
What is the rock evidence?
rock formation in S.America match Africa, folded mountain and coal fields, there is salt in Michigan and it forms near the equator, coal is formed in swampy climates and is found in Antarctica, limestone from coral reefs is found in West texas
What are the Mid-Oceanic Ridges?
underwater mountains with a deep crack (rift valley)
How is the new ocean floor made?
Lava oozes from the crack and forms new ocean floor, the new ocean floor pushes the old floor outward
Where are the youngest and oldest rocks located?
the youngest rocks are near the oceanic ridge and the oldest rock is farther away from the ridge
What does ocean floor spreading cause the continents to do?
spread apart
What is subduction?
process in which teh earth's crust plunges back into the earth
How old are the oldest rocks on land?
4 billion years old
How old are the oldest rocks in the ocean?
200 million years old
What happens to the plates during ocean floor recycling?
the less dense oceanic plate is pushed under more dense continental plate
Where do trenches form?
in areas of subduction
What forms in areas of subduction?
mountains and trenches
What are tectonic plates?
the study of how the lithospheric plates move to shape the surface of the crust
How many major plates are there?
How many minor plates are there?
What are the three types of boundaroes?
convergent, divergent, and strike-slip
What is a convergent boundary
plates that are coming together (trenches and mountain ranges)
What is another name for convergent boundary?
What is a divergent boundary?
plates that are moving apart or spreading
What is a strike-slip boundary?
two plates grind together as they slip past eachother
What forms at convergent boundaries?
trenches and mountain ranges
What forms at divergent boundaries?
mid-ocean ridges
What forms at stike-slip boundaries?
San Andreas Fault
What is another name for divergent boundary?
What is another name for strike-slip?
What are the three major zones for Earthquakes and Volcanoes?
Ring of Fire, Mediterranean Zone, Mid-Atlantic Ridge
What are the three major zones located at?
major plate boundaries
WHat happens at the Ring of Fire?
subduction happens here, convevrging palte boundaries
What do the movement of the plates cause?
earthquakes (moving plates cause ground to shake) and volcanoes (subduction forces magma to earth's surface)
What is an earthquake?
a trembling that happens from sudden movement of the earths crust
What is a fault?
a break in the earth's crust which the crust moves along
What is the focus?
the underground origin of the earthquake
What is the epicenter?
the point on the earth;s surface directly above the focus
What are seismic waves?
earthquake waves
What do the P-waves do?
push-pull, travel through solids, liquids, and gasses, the fastest waves
What do the S-waves do?
side-to-side, travel through solids, second fastest waves
What do the L-waves do?
up-and-down, destructive waves, slowest
What is a seismograph?
an instrument that detects and measures seismic waves
What is a seismogram?
aa record of seismic waves recorded by a seismogrpah
what does the S-P interval tell
What does the amplitude tell?
How many stations are required to locate the epicenter?
3 triangulation
What is magnitude?
a measure of the amount of energy released by an earthquake, as indicated on the Richter Scale
What is the Richter Scale?
a scale used to measure the magnitude of earthquakes, rates magnitude on scale from 1-10.
What is each step on the Richter Scale?
10X more powerful and 30X more energy
What is the San Andreas Fault?
classic Strike-Slip Fault, the Pacific Plate was moving NW and the N. American plate was moving SE
What causes smaller faults?
stress from movement of plates
What are the three types of volcanoes?
Cinder cones, composite, and shield volcanoes
Where are cinder cones and composites formed?
convergent boundaries
What is a cinder-cone?
steep sides formed from pyroclastic flow
What are two composite volcanoes?
Mt. Vesuvius and Mt. St Helens
What is a composite volcano?
most common form of volcano, cone shaped, violent eruptions, no "lava", pyroclastic flow
Where do shield volcanoes happen?
divergent boundaries and Hotspots
What are Shield Volcanoes?
smooth flowing, relatively calm, eruptions not as violent, gently sloping sides
What is magma called when it reaches the surface of the earth?
What are the two types of lava?
Pahoehoe and Aa
what is Pahoehoe?
runny lava "ropey"
What is Aa?
rough, jagged lava, "a painful surface to walk on"
What are Hotspots?
unusually hot areas, not at a plate boundary, where magma breaks through the crust to form volcanoes
How were the Hawaiian Islands formed?
the Pacific Plate moving northwestward over hotspot, forms a chain of islands
How does the age incrase of the islands?
age incrases from southeast to northwest
What is the youngest island?
What are the two volcanoes on Hawaii?
Mauna Loa and Kilauea
What is special about Kilauea?
most active in the world
What is the oldest of the islands?