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84 Cards in this Set
- Front
- Back
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What is the crust?
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the outermost layer of the earth
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What is the crust made of?
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it is rigid and is made up of very thin solid rock
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What is the thickness of the crust?
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It varies little (5km-300km)
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Where is the crust thinnest and thickest?
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It is the thinnest under oceans and the thickest under mountains.
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What are the three parts of the mantle?
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the lithosphere, asthenosphere, and mesosphere
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What is the lithosphere made of?
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the crust and rigid layer
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What is the lithosphere divided into?
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tectonic plates
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Why does the lithosphere float on the asthenosphere?
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because it is less dense
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What is the asthenosphere?
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the soft layer that the lithosphere moces on (liquid hot magma)
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What is the mesoshpere?
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the main thickest layer of the mantle
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What are the two parts of the core?
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outer core and inner core
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what is the outer core made of?
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liquid nickel and iron
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What is the inner core made of?
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solid nickel and iron
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Why is the inner core made of solid nickel and iron?
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because of the pressure that is put on it
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Why would it be thought that the continents are drifting?
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because Alfred Wegener examined the continents and noticed that the coasts fit together
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Why would it be thought that the continents are drifting?
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because Alfred Wegener examined the continents and noticed that the coasts fit together
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What is it called when the Earth was one single land mass
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Pangaea
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What are the two types of evidence there is for the drifting continents?
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fossil evidence and rock evidence
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What is the fossil evidence?
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there are identical fossils in Africa and S. America
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What is Glosspteris
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a fossil found in S. Africa, Australia, India, and Antarctica
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What is the rock evidence?
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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
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What are the Mid-Oceanic Ridges?
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underwater mountains with a deep crack (rift valley)
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How is the new ocean floor made?
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Lava oozes from the crack and forms new ocean floor, the new ocean floor pushes the old floor outward
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Where are the youngest and oldest rocks located?
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the youngest rocks are near the oceanic ridge and the oldest rock is farther away from the ridge
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What does ocean floor spreading cause the continents to do?
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spread apart
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What is subduction?
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process in which teh earth's crust plunges back into the earth
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How old are the oldest rocks on land?
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4 billion years old
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How old are the oldest rocks in the ocean?
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200 million years old
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What happens to the plates during ocean floor recycling?
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the less dense oceanic plate is pushed under more dense continental plate
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Where do trenches form?
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in areas of subduction
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What forms in areas of subduction?
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mountains and trenches
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What are tectonic plates?
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the study of how the lithospheric plates move to shape the surface of the crust
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How many major plates are there?
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7
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How many minor plates are there?
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9
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What are the three types of boundaroes?
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convergent, divergent, and strike-slip
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What is a convergent boundary
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plates that are coming together (trenches and mountain ranges)
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What is another name for convergent boundary?
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destructive
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What is a divergent boundary?
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plates that are moving apart or spreading
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What is a strike-slip boundary?
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two plates grind together as they slip past eachother
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What forms at convergent boundaries?
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trenches and mountain ranges
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What forms at divergent boundaries?
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mid-ocean ridges
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What forms at stike-slip boundaries?
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San Andreas Fault
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What is another name for divergent boundary?
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constructive
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What is another name for strike-slip?
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conservative
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What are the three major zones for Earthquakes and Volcanoes?
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Ring of Fire, Mediterranean Zone, Mid-Atlantic Ridge
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What are the three major zones located at?
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major plate boundaries
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WHat happens at the Ring of Fire?
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subduction happens here, convevrging palte boundaries
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What do the movement of the plates cause?
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earthquakes (moving plates cause ground to shake) and volcanoes (subduction forces magma to earth's surface)
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What is an earthquake?
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a trembling that happens from sudden movement of the earths crust
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What is a fault?
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a break in the earth's crust which the crust moves along
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What is the focus?
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the underground origin of the earthquake
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What is the epicenter?
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the point on the earth;s surface directly above the focus
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What are seismic waves?
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earthquake waves
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What do the P-waves do?
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push-pull, travel through solids, liquids, and gasses, the fastest waves
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What do the S-waves do?
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side-to-side, travel through solids, second fastest waves
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What do the L-waves do?
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up-and-down, destructive waves, slowest
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What is a seismograph?
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an instrument that detects and measures seismic waves
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What is a seismogram?
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aa record of seismic waves recorded by a seismogrpah
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what does the S-P interval tell
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distance
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What does the amplitude tell?
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magnitude
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How many stations are required to locate the epicenter?
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3 triangulation
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What is magnitude?
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a measure of the amount of energy released by an earthquake, as indicated on the Richter Scale
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What is the Richter Scale?
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a scale used to measure the magnitude of earthquakes, rates magnitude on scale from 1-10.
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What is each step on the Richter Scale?
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10X more powerful and 30X more energy
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What is the San Andreas Fault?
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classic Strike-Slip Fault, the Pacific Plate was moving NW and the N. American plate was moving SE
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What causes smaller faults?
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stress from movement of plates
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What are the three types of volcanoes?
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Cinder cones, composite, and shield volcanoes
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Where are cinder cones and composites formed?
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convergent boundaries
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What is a cinder-cone?
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steep sides formed from pyroclastic flow
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What are two composite volcanoes?
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Mt. Vesuvius and Mt. St Helens
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What is a composite volcano?
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most common form of volcano, cone shaped, violent eruptions, no "lava", pyroclastic flow
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Where do shield volcanoes happen?
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divergent boundaries and Hotspots
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What are Shield Volcanoes?
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smooth flowing, relatively calm, eruptions not as violent, gently sloping sides
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What is magma called when it reaches the surface of the earth?
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lava
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What are the two types of lava?
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Pahoehoe and Aa
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what is Pahoehoe?
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runny lava "ropey"
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What is Aa?
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rough, jagged lava, "a painful surface to walk on"
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What are Hotspots?
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unusually hot areas, not at a plate boundary, where magma breaks through the crust to form volcanoes
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How were the Hawaiian Islands formed?
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the Pacific Plate moving northwestward over hotspot, forms a chain of islands
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How does the age incrase of the islands?
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age incrases from southeast to northwest
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What is the youngest island?
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Hawaii
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What are the two volcanoes on Hawaii?
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Mauna Loa and Kilauea
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What is special about Kilauea?
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most active in the world
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What is the oldest of the islands?
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Kauai
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