Transcript San Andreas Fault - Hesperia Christian School

San Andreas Fault
A drive along the fault.
Background Information
The San Andreas is a Slip Fault…
What does that mean?
It is two pieces of earth slipping
past each other.
There are
Three types
Of faults:
1.Normal
2.Reverse
3.Slip
Why does the earth move?
The earth is dynamic!
That means it is in motion!
The earth is in layers…
The crust, the layer we live on floats on the
thick mantle, which is fluid.
The Earth’s Crust
The earth’s crust is not one whole piece…it
is in pieces that move around…
Scientists call these pieces “plates” and the
study of the movement of these plates is
called Plate Tectonics.
The San Andreas Fault
The San Andreas Fault is a boundary
between the North America Plate and the
Pacific Plate.
These two plates are both sliding past each
other and in some places the Pacific Plate
is sinking beneath the other.
How do earthquakes happen on the fault?
As the plates move past each other, the
rocks get stuck and build up energy.
Eventually, the rocks can no longer
withstand the build up and they break!!
Result:
How often does the San Andreas fault
produce large earthquakes?
• Pallett Creek:
– every 130 years on average
• But varies from 45 to 300 years
• Wrightwood:
– every 100 years on average
• But varies from 62 to 192 years
Devore:
– Every 150 years on average
• So when should we expect the next earthquake?
• It’s been 193 years since the last one in San
Bernardino (in 1812).
How strong would the shaking be?
Factors that affect how strong the shaking in
an earthquake will be
1) Earthquake magnitude
2) How far away the earthquake is
3) Soil conditions
Earthquake Waves
Earthquakes create several different types
of waves.
p waves are compression waves
(like sound).
s waves are transverse waves that move
side to side or up and down.
The Beginning
At the start of the trip we must all first pick
up a forest pass from the Chevron station
at the bottom of the pass.
We will meet up at the McDonald’s adjacent
to the Chevron station.
You must pick up your $5 pass first!
Mormon Rocks
Our first stop is the Mormon Rocks.
Mormon Rocks
The Mormon Rocks were created
thru uplift of the fault.
They are sandstone,
but are fairly resistant
to weathering.
Mormon Rocks
Mormon Rocks
Lone Pine Canyon
The next part of the trip is along Lone Pine
Canyon Road. This road and canyon
directly follow the fault…In fact, this
canyon is a direct result of the fault.
Marble Quarry
Traveling up Lone Pine Canyon Road
towards Wrightwood, we stop at an old
Marble quarry.
We stop here to collect marble samples
before moving into Wrightwood.
Look for other rocks like actinalyte as well!
Marble Quarry
Marble Quarry
Plants at the Marble Quarry
At the quarry you will
see various plant life
representative of the
lower valley.
Plants at the Quarry
Plants at the Quarry
Plants at the Quarry
Lone Pine Canyon Road through
Wrightwood
We follow Lone Pine Canyon Road to
Highway 2 and head west on Hwy. 2.
The fault runs through Wrightwood and here
in Wrightwood is the sight of one of the
largest earthquakes in the history of the
fault, the 1857 quake.
Big Pine Information Center
The Big Pine
Information Center is
the next stop.
Here we will look in the
small store and walk
along a nature trail.
Big Pine Information Center
This tower sits on the fault.
It is the highest point on the
San Andreas Fault.
Big Pines Highway
We travel along Big Pines Highway now on
the edge of the fault!
Appletree Campground
We will stop on the side of the road
(Completely off the road!) and walk across
the road to the Appletree Campground
where we will then walk up a short forestry
road to look down at the fault and collect
some “fault flower”.
Lunch!!!
Lunch will be taken at a
little off the road
picnic area called
Mescal Picnic Area.
Yummm…
Jackson Lake
Last stop…
Jackson Lake
Jackson Lake is a
creation of the fault.
It is a sag pond…an
area which sank
as a result
of the fault.
Jackson Lake
Go Home!!!
Head back through Wrightwood on
Highway 2 and to
Highway 138…
Have a Safe Trip!
God Bless!