By 10 grade What is an earthquake Simply earthquakes are the rumblings shaking or rolling of the earths 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 u ID: 161763
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Slide1
EarthquakeS
By
: 10 gradeSlide2
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. Slide3
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. Slide4
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. Slide5
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.Slide6
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.Slide7
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 won´t move through a liquid medium.
The
image
shows
the
type
of
movement
it
causes. Slide8
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
.
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.htmlSlide9
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
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.
WHAT CAUSES EARTHQUAKES?Slide10
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.Slide11
The epicenter is the point on the earth's surface vertically above the
hypocenter, point
in the crust where a seismic rupture begins
.
EPICENTERSlide12
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. Slide13
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 magnitudeOf 9.5.