WHAT IS AN EARTHQUAKE ? Simply, earthquakes are the rumblings,
shaking or rolling of the earth's surface. It is usually what
happens when two blocks of the earth suddenly slip past one
another, or break apart from each other as a result of tension
caused by prolonged energy build up. Simply, earthquakes are the
rumblings, shaking or rolling of the earth's surface. It is usually
what happens when two blocks of the earth suddenly slip past one
another, or break apart from each other as a result of tension
caused by prolonged energy build up.
Slide 3
WHAT IS A MAINSHOCK? The main shock is the largest earthquake
in a sequence, sometimes preceded by one or more foreshocks, and
almost always followed by many aftershocks.
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WHAT IS A FORESHOCK? A foreshock is an earthquake that occurs
before a larger seismic event (the main shock) and is related to it
in both time and space. In other words is the small shake that
happens right before the earthquake. A foreshock is an earthquake
that occurs before a larger seismic event (the main shock) and is
related to it in both time and space. In other words is the small
shake that happens right before the earthquake.
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WHAT IS AN AFTERSHOCK? Aftershock, any of several
lower-magnitude earthquakes that follow the main shock of a larger
earthquake. An aftershock results from the sudden change in stress
occurring within and between rocks and the previous release of
stress brought on by the principal earthquake. Aftershocks occur in
rocks located near the epicenter or along the fault that harboured
the principal quake. Although the shaking intensity associated with
most aftershocks is small compared with that of the principal
earthquake.
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P-WAVES: P- waver or compressional wave, is a seismic body wave
that shakes the ground back and forth in the same direction and the
opposite direction as the direction the wave is moving. P- waver or
compressional wave, is a seismic body wave that shakes the ground
back and forth in the same direction and the opposite direction as
the direction the wave is moving.
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S-WAVES (SECONDARY WAVES) Is wave a type of the secondary type
of wave, comes after the primary wave. Is slower because it only
moves solid rock, it wont move through a liquid medium. The image
shows the type of movement it causes.
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SIESMIC WAVES Seismic waves are the waves of energy caused by
the sudden breaking of rock within the earth or an explosion. They
are the energy that travels through the earth and is recorded on
seismographs. Seismic waves are the waves of energy caused by the
sudden breaking of rock within the earth or an explosion. They are
the energy that travels through the earth and is recorded on
seismographs. The two main types of waves are body waves and
surface waves. Body waves can travel through the earth's inner
layers, but surface waves can only move along the surface of the
planet like ripples on water. The two main types of waves are body
waves and surface waves. Body waves can travel through the earth's
inner layers, but surface waves can only move along the surface of
the planet like ripples on water.
http://www.geo.mtu.edu/UPSeis/waves.html
http://www.geo.mtu.edu/UPSeis/waves.html
http://www.geo.mtu.edu/UPSeis/waves.html
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An earthquake originates naturally at or below the surface. An
earthquake originates naturally at or below the surface. 3 MAIN
CAUSES: They can be connected to volcanic eruptions; they are in
fact very common in areas of volcanic activity where they either
progress or accompany eruptions. They can be connected to volcanic
eruptions; they are in fact very common in areas of volcanic
activity where they either progress or accompany eruptions. They
can be generated by Tectonic activity associated with plate margins
and faults. They can be generated by Tectonic activity associated
with plate margins and faults. Earthquakes are the vibrations
caused by rocks breaking under stress. The underground surface
along which the rock breaks and moves. Earthquakes are the
vibrations caused by rocks breaking under stress. The underground
surface along which the rock breaks and moves. WHAT CAUSES
EARTHQUAKES?
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WHAT IS THE FOCUS OF AN EARTHQUAKER? The location where the
earthquake begins. The ground ruptures at this spot, then seismic
waves radiate outward in all directions.
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. The epicenter is the point on the earth's surface vertically
above the hypocenter, point in the crust where a seismic rupture
begins. EPICENTER
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HOW EARTHQUAKES ARE RECORDED? Are recorded by instruments
called seismographs. The recording they make is called a
seismogram. The seismograph has a base that fits in the ground, and
a huge weight that hangs free. The base of the seismograph moves
when the earthquake causes the ground to shake, but the weight does
not move. The chain is the one that hold all the movement.
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WHY CAN WE FEEL EARTHQUAKES HUNDREDS OF MILES AWAY? This
happens because when an earthquake starts, the ground cracks,
producing seismic waves that go through the tectonic plate. Did you
know? That the biggest earthquake recorded happened in Chile on May
22 1960 with an magnitude Of 9.5.