Who is Alfred Wagner? When did he come about?
German meteorologist and in 1912
What did Alfred Wagner test?
His hypothesis that SA and AF were once united as a single continent.
What are the four things that Alfred found?
That the coastlines of SA and AF were similarly shaped,found matching rock types of east coast of SA and west coast of Africa, found some species of fossil organisms on both continents, and that mountain ranges matched in NA and Europe
What is Pangea?
Super continent composed of all of today's separate continents.
Sonar was the ---
Map of a sea floor
What did Sonar find
A 43000 mile long mountain range running across the bottom of all the worlds ocean.
The 43000 mile long mountain range is also called the
Mid ocean ridge
The manometer ---
Pattern of alternating normal and reversed polarity rock symmetrical about and parallel to the MOR.
Sea floor spreading
What are the three types of plate boundaries?
Divergent, Convergent, Transform
What are the three subgroups of convergent?
Ocean continent, Ocean Ocean, Continent continent
Vibration of the earth caused by the rapid release of energy typically due to slippage along a fault.
Define a Fault
A fracture across which there is displacement
Why are Earthquakes important to study because:
It can devastate population centers. It can study the details of the earths interior
There are ____ quakes a year that can be felt
There are____ year that are ____
75 (000?) large enough to do damage.
Where do large earthquakes typically occur?
In remote regions
What kind of convergent boundaries is Japan, chile/Alaska and Turkey?
Japan= Ocean/Ocean Chile/Alaska=Ocean/Continent Turkey=Continent/Continent
Point on the fault where rupture occurs
Point on the surface above the focus
Study of waves
What are the three types of Seismic Energy Waves
Primary wave, Secondary Wave and Surface Wave
What does a Seismometer do?
A device that measures earthquakes
The longer the distance the farther ___
away it occurred
Directions come from _____
You need at least three stations to ___
Determine exactly where an earthquake occurs
What are the characteristics of Primary Waves
Also called compression. Small amplitude and high frequency.Travels the fastest. Travel through solids and liquids.
What are the characteristics of Secondary Waves
Also called sheer. Slower than primary waves. Travels only through solid. Ground motion perpendicular to the direction that wave travels.
What are the characteristics of Surface Waves
Slower than primary and secondary. Travels along the surface. Causes damage.
What are the three types of scales used to measure the measurement of quakes?
Intensity Scale, Magnitude Scale, Moment Magnitude Scale
Define Intensity Scale
A pre-seisometer. A measure of the degree of shaking at a location based on the amount of damage to structures
What are the limitations of the Intensity Scale
Quakes don't always occur where there are structures, How to assign a degree of shaking, Nature of the material that the structure is made of
Define Magnitude Scales
Richter Magnitude Scale. Based on the amplitude of the largest surface wave measure on a seismometer and on the quake is from your seismic station as determined from a travel time graph
If an earthquake is above 8 than it is ____
Define Moment Magnitude Scale
Used to test the "great" quakes.
What is Predicatability
Is there a cyclicity of rupture on known faults. Foreshocks- Preceed the "main event"
What are some destructive phenomena due to quakes?
Seismic vibration, tsunamis, fires due to rupture of gas lines, landslides and mudslides
Define Seismic Vibration?
Liquification of the loss of cohesion between sedimentary particles due to shaking
Due to vertical motion of the sea floor
What are some characteristics of a tsunami
Travels 400-600 mph and has very long wavelengths. As the wave begins to "feel" the bottom it slows down, it increases in steepness
Tides have nothing to do with ___
What are the two types of a Volcanic Eruption?
Gentle, Hawaiian style and Explosive/Catastrophic
What are the factors that control eruptive style?
Viscosity. Resistance to flow of the magma
What are two other factors that control eruptive style?
Chemical Composition and amount of dissolved gasses in the magma
Define Chemical Composition
Mafic (basaltic) lava has very low viscosity (hawaiian style, very funny, flows easily. Felsic (granite) lava has high viscosity (catastrophic) and very sticky
What are the characteristics of Basaltic Eruptions
Lava and gas, cools and forms 2 types of lava flows
What are the two types of lava flows for basaltic eruptions?
Pahoehoe (smooth texture) and Aa- Sharp, broken fragments of basaltic rubble
What are the characteristics of Felsic Eruptions?
Pyroclastic Material-Broken fragments of rock and solidified lava. and gases
Define volcanic dust in felsic eruptions?
Pulverized rock and volcanic ash
What are the three main types of Volcanoes?
Shield, Cinder cones and Composite
What is a Shield Volcano?
Built from very low viscosity, basaltic magma. Ex: Hawaii
Define Cinder cones?
Smallest, Basaltic. Due to built up cinders . Single even eruptions-days to months. Flows from fissures at the base of the cone.
Gravel sized particles of basaltic around original vent
Define a Composite volcano?
Ocean continent convergent plate boundaries. Ex: Andes, Mt. Shaste, Mt. Ronier, Mt. St. helens (cascade)
Composite Volcanos are made of ___
Lava and Pyroclastics
Composite volcanoes are also called ____ volcanos
Composite Volcanos are made up of ____
Lava and Pyroclastics
Composite Volcanoes have ___
Steep upper parts, Broad shoulders and lower viscosity magma
What is a Caldera Volcano?
Type of volcano that is the result of explosive volcanos. Massive eruption and failure of a composite volcano
Name some places that are ocean-ocean convergent plate boundaries?
Japan, Indonesia, Aleatian and Phillipines
What are some destructive aspects of a composite volcano?
Low viscosity, basalt, "Hawaiian style" the lava flows and damage property
What is the second destructive aspect of composite volcanos?
High Viscosity-Erupting rock frogs, volcanic dust, lava superheated gases. (Pyroclastic flaws)
What is LAHAR?
Volcanic mudslides due to the rapid melting of ice/snow/glacier/ on composite volcanoes
What are the volcanic land forms?
Volcanic rock and Volcanic pipe
Define Volcanic rock
Reminant of solidified magma in the "throat" of an extinct eroded volcano
Define Volcanic pipe
Subsurface conduct filled with solidified magnet
What are two examples of a Volcanic Rock
Devils tower, shiprock
What are fissure eruptions?
Low viscosity, basaltic
What is the Volcanic sill?
Subsurface horizontal lava flow
Magma is squeezed ____
Horizontally between subsurface layers
Define Volcanic Dikes
Magma is squeezed through fractures that cut vertically across layers
The Sierra Navada Mountains is on a __
What is an example of a Divergent mid ocean ridge?
What is an example of a Rift Valley?
What is an example of Ocean-Ocean?
Alegian Islands, Japan, Caribbean, Indonesia
What is an example of Continent-Continent?
Collision of India+Area=Himalayas App
Define a Transform Plate boundary? (and example)
Plates that slide past one another. ex: San adreas fault system
Define Divergent plate boundaries
New crust is created as two or more plates pull away from each other. Oceans are born and grow wider where plates diverge or pull apart.
Define Convergent plate boundaries
Crust is destroyed and recycled back into the interior of the Earth as one plate dives under another.
_______ are areas in which crust is destroyed and recycled
Mountains and volcanoes are often found where ____
When an oceanic plate pushes into and subducts under a continental plate, the overriding continental plate is lifted up and a mountain range is created.
When two oceanic plates converge one is usually subducted under the other and in the process a deep oceanic trench is formed.
The marina trench is an example of?
Define Continent continent
When two continents meet head-on, neither is subducted because the continental rocks are relatively light and, like two colliding icebergs, resist downward motion.
A volcanic eruption where lava wells up through fissures in the earth's crust and spreads over a large area are called ___
What convergent plate boundaries is compressive uplift?
What convergent plate boundaries are volcanic ranges?
Define Crystal deformation
Change in the shape and/or the volume of a book of rock.
Crystal Deformation typically occurs due to?
What are the two main structures that results from crystal deformation?
Folds and Fractures.
Define a Fold
Result in "folded" mountains
Define a Fracture
Result in fault
Define Elastic Deformation
Apply stress deformation rock releases stress, rock returns to normal. But once the elastic limit is exceeded material can deform and either go brittle or break
What is the high/low temp like for deformation?
High temp-Ductile Low temp-Brittle
What is the pressure like for deformation?
High pressure-Deep crystal rocks-Ductile. Low pressure-Shallow crystal depths-brittle
What is the rock type for Deformation?
Igneous rocks typically fail under brittle deformation. Sed/Met-Deformation under ductile deformation
Folds are due to___
Low stress/long time is____ and high/rapid stress is ___
Oldest rocks at center is ___ and younger rocks at center is ___
Aucline and Syncline
Faults are due to___
Strike slip faults are ______
Horizontal motion and easily detectable because they offset linear features.
All transform plates are _______ but not all ___
Strike slip faults but not all strike slip faults are plate boundaries
Dip slip faults are ____
Vertical motions on the faults
When the wall is up it is due to ___and it is ____. When the wall is hanging up it is due to ___ and it is __
Extension and normal dip-slip faults. Compression and reverse dip-slip faults