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earthquakes

Terms in this set (42)

earthquake
rapid vibration of earth due to release of energy
focus
point within the earth where the earthquake starts
epicenter
location on the surface directly above the focus
Faults
fractures in earth where movement has occured
elastic rebound hypothesis
when rocks are deformed they first bend and then break, releasing stored energy
elastic energy
most earthquakes are produced by the rapid release of ____ _____
aftershocks
the movements that follow a major earthquake often produce smaller earthquakes called __________
foreshocks
small earthquakes that come before a major earthquake
seismographs
instruments that record earthquake waves
surface waves
seismic waves that travel along the earth's outer layer. Travel along the ground. Move in an up-and-down motion
P waves
push pull waves- they push (compress) and pull (expand) aka compression waves
S waves
shake the particles at right angles to their direction of travel aka transverse waves
seismogram
shows all three types of seismic waves-- surface, S and P waves
travel-time graphs
these from 3 or more seismographs can be used to find exact location of an earthquake epicenter
intensity and magnitude
2 types of measurment used to describe the size of an earthquake
intensity
the measure of the amount of earthquake shaking at a given location based on the amount of damage
Magnitudes
measurements of the size of seismic waves or the amount of energy released at the source of the earthquake
richter scale
outdated scale for measuring the magnitude of earthquakes. Uses a logarithmic scale. Only useful for small, shallow earthquakes. Most news reports use the richter scale
moment magnitude
the amount of displacement that occurs along a fault zone. Most widely used measurement for earthquakes
intensity of vibrations, structure's build, and design
damage to buildings depends on?
liquefaction
where loosely consolidated sediments are saturated with water, earthquakes can cause a process known as?
tsunamis
most deaths are caused by this natural disaster. these destructive waves are sometimes called tidal waves
tsunami
triggered when a slab if the ocean floor is displaced vertically along a fault
landslides
greatest damage to structures is usually caused by ______
short-range predictions
methods for ____-____ ________ of earthquakes have not been successful
seismic gap
an area along a fault where there has not been any earthquake activity for a long period of time
crust, mantle, core
earth consists of 3 major zones defined by chemical composition
crust
thin, rocky outer layer of earth, divided into oceanic and continental
oceanic crust
composed of igneous rocks -basaltic. thinner than continental
continental
consists of many rock types- mainly consists of granitic rock
mantle
a solid, rocky shell that extends to a depth of 2890 km.
core
sphere composed of an iron nickel alloy.
earth's interior
___'s _____ has a gradual increase in temperature, pressure and density with depth.
lithosphere, asthenosphere, outer core, and inner core
earth is divided into layers based on physical properties
lithosphere
earth's outer most layer and uppermost mantle forms a relatively cool, rigid shell called?
asthenosphere
beneath lithosphere lies a weak layer with temp/pressure conditions that may result in slight melting.
outer core
liquid layer. the flow of metallic iron within this zone generates Earth's magnetic field.
inner core
a sphere with a higher temp., which has compressed material in a solid state by the immense pressure
basaltic composition
the crust of the seafloor has a?
meteorites
surprisingly, ______ that collide with earth provide evidence about earth's inner composition
circum pacific belt
an area where large numbers of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean.
mercalli scale
a seismic scale used for measuring the intensity of an earthquake.
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