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29 Cards in this Set
- Front
- Back
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Earthquake
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the vibration of Earth produced by the rapid release of energy
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Focus
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the point within Earth where the earthquake starts
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Epicenter
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the location on the surface directly above the focus
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Faults
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fractures in the Earth where the earthquake starts
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Elastic Rebound Hypothesis
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produced by the rapid release of elastic energy stored in rock, which has been subjected to great force, and when the strength of the rock is exceeded it breaks
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Aftershock
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a small earthquake that follows the main earthquake
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Foreshock
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a small earthquake that often precedes a major earthquake
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Seismograph
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instruments that record earthquake waves
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Seismograms
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are traces of amplified, electronically recorded groundmotion made by seismographs
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Surface Waves
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seismic waves that travel along Earth's outer layer
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P Waves
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push-pull waves that push and pull in teh direction that the wave travels
travel through solid, liquids, and gases have the greatest velocity of all earthquake waves |
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S Waves
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seismic waves that travel along Earth's outer layer
shake particles to right angles to the direction that they travel travel only through solids slower velocity than P Waves |
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Richter Scale
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based on the amplitude of the largest seismic wave
each unit of Richter magnitude equates to roughly 32-fold energy release doesn't adequately estimate the size of very large earthquakes |
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Momentum Magnitude
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derives from the amount of displacement that occurs along fault zones
most widely used, because it is the only magnitude scale that estimates the energy released measures very large earthquakes |
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Factors that Determine the Violence of an Eruption
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Composition of Magma
Temperature of Magma Amount of Dissolved Gases in Magma |
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Viscosity
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the measure of a material's resistance to flow
High Viscosity-Thicker Low Viscosity-More Fluid |
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Factors Affecting Viscosity
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Temperature(hotter magmas=less viscous
Composition(silica content) High Silica=High Viscosity Low Silica=more fluid |
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Vent
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an opening in the surface of Earth through which molten rock and gases are released
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Pahoehoe Lava
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resembles braids in ropes
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Aa Lava
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rough, jagged blocks
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Pyroclastic Material
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particles produced in volcanic eruptions
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Types of Volcanoes
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Shield Volcanoes
Cinder Cones Composite Cones |
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Volcano
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a mountain formed of lava and/or pyroclastic material
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Crater
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a depression at the summit of a volcano or that which is produced by a meteorite impact
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Conduit
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carries gas-rich magma to the surface
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Shield Volcano
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are broad, gently sloping volcanoes built from fluid basaltic lavas
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Cinder Cones
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small volcanoes built primarily of pyroclastic material ejected from a single vent
Steep Slope Angle Rather Small in Size Frequently Occur in Groups |
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Composite Cones
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composed of both lava flows and pyroclastic material
most are adjacent to the Pacific Large in Size Interbedded Lavas and Pyroclastics Most Violent Type of Activity |
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Calderas
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depressions in volcanoes
nearly circular formed by collapse size exceeds one kilometer in diameter |
