Transcript Chapter 5 Atoms to Minerals

For 10.1-10.2
There is no power point to this
chapter as the lessons were
based on the Geode program.
You will have to copy someone
else NOTES ONLY.
10.3
Chapter 10
Earthquake Hazards
Take notes by writing just the
yellow words and any other
you feel you will need!
Damage from Earthquakes
At the San Andreas fault separates
two plates; Pacific and North
American.
As these plates try to slide past
each other, pressure builds and
all waves leave at the same time
http://www.acs.psu.edu/drussell/demos/waves/wavemotion.html
P waves
S Waves
Longitudinal &
Transverse
Raleigh
Waves
Which Waves are
Primary?
Secondary?
Longitudinal?
Raleigh?
Ground Shaking and Foundation Failure
Liquefaction occurs when loose soil turns to a
thick, soupy liquid during an earthquake.
As liquefaction takes place, buildings and other
structures quickly collapse into the soft dirt.
Seismic shaking is a measure of how much
ground movement occurs during a quake as
measured by seismographs.
Aftershocks and Fire
After a major quake, the ground usually shakes
again many times.
The smaller quakes are called aftershocks.
This can continue to weaken already damaged
buildings and cause gas lines to break.
After many large quakes, damaged gas lines
and cooking stoves can cause massive fires.
Tokyo 1923, San Francisco 1907, and many
other cities experience disastrous fires.
Tsunamis
In 1964, an undersea displacement
caused a huge earthquake near Alaska.
This release of energy produce a huge wave
called a tsunami. It grew in height as it hit the
shoreline off Crescent City, CA killing 11…
Recall that a tsunami is a wave formed when the
ocean floor shifts suddenly during an earthquake.
As a tsunami nears land and begins to break, the
tsunamis grows to enormous size.
Scientists have evidence that
in the past 200 years, more
than a dozen locally generated
tsunamis have struck the
California coastline.
In 2011, a huge earthquake in
Japan caused a small Tsunami that
killed another person in Crescent City, CA.
Preventing Earthquake Damage
Now that we understand quakes better, we have
started to design structures to be safer.
Items in homes and offices can be strapped
down or secured so they are less likely to fall.
After a quake we can use the modified
Mercalli scale to describe the effects
of the seismic shaking that occurred.
This scale is a measure of how strong
an earthquake is felt and how much
damage it did at a particular location.
The effects of a 12 on the modified Mercalli
scale are the same as a Richter scale
magnitude of 8+.
Earthquake Risk
This map shows where the highest risk is for
future quakes – on west coast
Some of this information is based on major
quakes that occurred within the last 200 years.
For example, In 1811 and 1812 New Madrid,
Missouri experience three major quakes.
Recent California Earthquakes
1906 San Francisco, 7.8 deaths 3000
1933 Long Beach, 6.4 deaths 115
1971 San Fernando, 6.6 deaths 65
1989 Loma Prieta, 6.9 deaths 63
1994 Northridge, 6.7 deaths 60
Predicting Earthquakes
To be effective, an earthquake prediction must
show where, when and how strong the quake
will be.
Seismic gaps show places along faults that have
not had earthquakes for some period and may
be overdue.
Quiz
1. As tectonic plates try to slide past each other,
pressure builds. This can cause? earthquakes
Liquefaction occurs when water-soaked soil
2. __________
turns to a thick, soupy liquid during an earthquake.
3. After a major quake, the ground can continue to
shake many times, these are known as? aftershocks
4. After many large quakes, damaged gas lines
and cooking stoves can cause massive? fires
tsunami nears land and begins to
5. As a _________
break, it grows to enormous size.
End