2. Along the “meeting point” a
fault line is created where One plate moves in one
huge friction is caused that direction, as the other(s)
results in an earthquake. go(es) in the opposite
direction.
In the mean time a gap is
created behind each of
the plates as it moves
forward and this is called
a fault.
3. • Conservative (Passive) plate boundaries occur where two
plates slide horizontally past each other. This does not cause
the loss or creation of land although as each plate moves in
the opposite direction to the other, huge friction is caused. This
results in an earthquake as the Earth is shaken by the
movement of the two huge masses of rock, due to the
enormous amount of energy being released; and these effects
are particularly felt in buildings on the fault line where the two
plates meet. The areas behind each plate where a gap is left
also shake as they “fall” momentarily.
• The best known example of a Conservative (Passive)
plate boundary can be found along the west coast of the
USA where the Pacific Plate is moving in a North
Westerly direction and sliding past the North American
Plate. This plate boundary is the cause of the San
Andreas Fault. Other examples of this type of fault
include the Alpine Fault in New Zealand and the North
Anatolian Fault in Turkey.
5. The San Andreas Fault is a geological fault that runs a length of
roughly 800 miles through western and southern California in the
United States. The fault, a right-lateral strike-slip fault, marks a
transform (or sliding) boundary between the North American
Plate and the Pacific Plate. All land west of the fault on the
Pacific Plate is moving slowly to the northwest while all land east
of the fault is moving to the southwest (relatively southeast as
measured at the fault) under the influence of plate tectonics. It
slices California in two from Cape Mendocino to the Mexican
border. San Diego, Los Angeles and Big Sur are on the Pacific
Plate. San Francisco, Sacramento and the Sierra Nevada are on
the North American Plate. The rate of slippage averages
approximately 33-37 mm/year across California. This fault effects
both Los Angeles and San Francisco.
Projected motion indicates that the Gulf of California will expand
northward at the same time that the landmass west of the fault,
including the Baja California peninsula and the California coast
slides past San Francisco, then continuing north-westward as an
island mass toward the Aleutian Trench, over a period of around
twenty million years.
6. The arrows on this image show the
relative motion of the two plates. The
plate to the left of the map is the Pacific
Plate, meaning the plate to the right is
the North American Plate. As you can
see the two plates are moving in
opposite directions to one another.
Blocks on opposite sides of the San
Andreas fault move horizontally. If a
person stood on one side of the fault
and looked across it, the block on the
opposite side would appear to have
moved to the right. Geologists refer to
this type fault displacement as right-
lateral strike-slip. This is a movement
which has occurred along the fault.
7. In the recent past, scientists have attempted to predict
when the next big earthquake will occur on the San
Andreas Fault. In the late 1980s they predicted that in
1993 an earthquake would occur, however this did not
happen until 2004 in Parkfield. To predict this they used
previous figures and dates and decided that 1993 would
probably be the next date for an event of huge scale in
this area. Even though these predictions are becoming
more and more accurate they will never be 100% correct
and no-one truly knows when the next potential
humanitarian disaster will happen.
8. This map indicates all
of the places effected
by the San Andreas
Fault including large
cities such as Los
Angeles and San
Francisco.
11. On the 18th of April, 1906 San Francisco experienced a huge earthquake,
with modern estimates giving the disaster a rating of 8.5 on the Richter
Scale. The earthquake was caused by the two main plates in the area
rubbing against each other thus creating a huge amount of friction. The
main shock epicenter occurred offshore about 2 miles from the city, near
Mussel Rock. It ruptured along the San Andreas fault both northward and
southward for a total length of 296 miles. San Francisco was devastated
by the event as buildings were destroyed and therefore livelihoods ruined
and this was worsened by the subsequent fires. The economic impact has
been compared with the more recent Hurricane Katrina disaster . The
tremors caused by the quake could be felt up to 80 miles from the fault.
700 people were killed in San Francisco with another 189 fatalities
reported in other areas of the west coast of the USA. The earthquake
caused the displacement of the mass majority of San Franciscans and in
response 11 refugee camps were built. Since this event the area has been
hit by many more earthquakes, most notably in 1989. However such
natural disasters can never be stopped as the area will always lie on the
San Andreas Fault.
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17. By James
Benson, Tom Hill,
Joe Taylor, Lewis
Herdson And Jack
Sherlock
