Download What are 3 types of plate movements

All about Earthquakes
By 3 Students
Table of
Contents
Chapter 1…………………………………………….Page 1
Chapter 2…………………………………………….Page 2
Chapter 3…………………………………………….Page 3
Chapter 1
There are three types of plate movements, the transform movement, the
convergent movement, and the divergent movement. Transform movements occur when
plates slide or grind past along transform faults. The San Andreas Fault is a good
example of a transform fault. Friction doesn’t allow plates to simply glide past each
other. When these transform movements slide past each other they can create massive
earthquakes. Convergent movements occur when 2 plates slide towards each other
forming either a subduction zone or an orogenic belt. Convergent boundaries are also
known as destructive boundaries. A subduction zone is when a dense oceanic plate
thrusts under the less dense continental plate. This can create a mountain chain or a chain
of volcanoes. Divergent movements occur when two plates slide apart from each other.
These are also known as constructive boundaries. This creates a space that is filled in
with crustal materials such as magma and rocks. These are powered by hot spots and can
make rift valleys.
The average amount of distance a plate will move is 0.66 to 8.50 centimeters per
year. Some plates like the Antarctic plate have a different speed of 2.05 centimeters per
year. Plate’s size can also vary greatly, from a few hundred to thousands of kilometers
across. The Pacific and Antarctic plates are among the largest. Plate thickness also
varies from less than 15 km for oceanic plates to around 200 km or more for ancient
continental plates. For example one part of the ocean can be down to 10 kilometers and
some parts of land can be up to 70 kilometers.
The 3 major layers of the Earth are the crust, mantle and inner/outer core. The crust
is the Earths outer most layer. It can be up to 20 miles thick on continents and down to 5
miles thick in the ocean. Most earthquakes occur in the Earth’s crust. The Earth’s crust
is thin and also brittle. The mantle is just below the Earth’s crust and extends all the way
down to the core. The mantle is about 6 miles below the oceanic plates and 19 miles
below the continental plates. The mantle is about 1800 miles thick and it takes up 80% of
the Earth. The mantle is composed of very hot dense rock. The outer core has melted
metals like nickel and iron. It is 1400 miles thick and it is so hot that the metals have
melted. The inner core begins about 4000 miles below the crust and it is 800 miles thick.
The metals in the inner core are not liquid but a solid because of all the pressure and heat.
The ring of fire is a zone where earthquakes and volcanoes frequently happen. The
ring of fire encircles a basin of the Pacific Ocean. It is shaped like a horseshoe and is
40,000 km long. Many series of oceanic trenches, island arcs and volcanic mountain
ranges are within the ring. 90% of the world’s earthquakes and 81% of the larger ones
occur within the ring. The ring of fire is where movement and collision of crustal plates
occur. This is what causes the earthquakes to occur. An example of one of these
movements is that the eastern region Nazca plate and Cocos plate subduct under the
South American Plate. The Nazca plate is colliding with the South American Plate.
Chapter Two
There are probably three major places in California where there are tons of
earthquakes. The San Andreas Fault along the west coast of California is probably the
most places where earthquakes happen. The San Andreas Fault is the most studied fault
in the world as well. The Geysers to the northeast is another place where a lot of
earthquakes happen. The South East has a large area of faults such as the San Jacinto
Fault, the Coyote Creek Fault, and the southern parts of the San Andreas Fault. A fault is
place were the earths crust is open and splitting apart due to tectonic plate activity.
The earthquakes happen because of the earths plates. The continents and oceans
are floating on the top of the mantle. Sometimes the plates collide and rub against each
other. This is where most earthquakes happen. California is right on the Ring of Fire,
which is the Pacific plate colliding with other plates. The ring of fire is where most
earthquakes in the world happen. In California’s case the North American plate is
rubbing against the Pacific plate. When the plates collide the earth shakes and the
earthquakes happen.
California is on the San Andreas Fault. The Pacific plate is heading up and the
North American plate is moving down. They meet at the San Andreas Fault. When they
rub against each other they cause earthquakes. This means that California must be
prepared. In 1906 a huge earthquake occurred along the San Andreas Fault. California
was devastated since then more earthquakes happened. Now California is making more
ways to avoid devastation.
Chapter Three
The first main earthquake danger is the effect of the ground shaking. Buildings can be
damaged by the shaking itself or by the ground beneath them settling to a different level
than it was before the earthquake (subsidence). Buildings can even sink into the ground if
soil liquefaction occurs. Liquefaction is the mixing of sand or soil and underground
water, or groundwater. The second main earthquake hazard is ground displacement or
ground movement along a fault. If a structure is built across a fault, or a dislodging of the
earths crust, the ground displacement during an earthquake could damage or rip apart the
structure. The third and fourth dangers of earthquakes are flooding and fire. The flooding
can occur when the earthquake breaks dams or levees along rivers. Fires can be started by
broken gas lines and power lines, or tipped over wood or coal stoves. Most of the hazards
to people are caused by man-made things. The real dangers to people are being crushed in
a collapsing building, drowning in a flood caused by a broken dam or levee, getting
buried under a landslide, or being burned in a fire.
The first thing you should do before an earthquake happens is to have your shelves
connected tightly to walls, and place heavy objects on lower shelves as well as storing
breakable items in low, closed cabinets. You should also hang things like pictures and
mirrors away from beds and anywhere people sit. Brace hanging light fixtures and repair
known defective electrical wiring and gas connections. Strap your water heater to studs in
the wall and bolt it to the floor. You can also repair any large existing cracks in walls or
foundations. Store poisons such as pesticides and liquids used for cleaning, as well as
flammable liquids, on bottoms shelves of latched cabinets. Then you should find a safe
place in each room (under sturdy furniture, against inside walls, away from glass). Find
safe places outdoors (away from buildings, trees, electrical lines, and bridges). It is really
important to teach your family members how to turn off gas, electricity, and water. It
would be a good idea to teach children how to dial 911 in an emergency. Have disaster
supplies on hand (flashlight and extra batteries, battery operated radio, first aid kit with
manual, emergency food and drinking water, non electric can opener, money, and sturdy
shoes). Make an emergency communications plan in case family members are separated
and need to be found.
If you happen to get caught in an earthquake then it is very important to stay away
from glass windows or statues. You should not be under any flimsy shelves either; they
could easily fall on you and knock you unconscious. It is said that if you do not have a
sturdy desk or anything like that, you should definitely try to find something sturdy
enough to hold on to. You should never leave the house or structure you are currently in
during heavy shaking. If you are in a town shopping it is the best idea to stay in that
building unless there is an electrical or gas leak. Move to a clear area if you can safely
walk. Avoid power lines, buildings and trees. If you’re driving, pull to the side of the
road and stop. Avoid stopping under overhead hazards. If you are on the beach, move to
higher ground. An earthquake can cause a tsunami.
There are a couple of different types of things you should have during the emergency.
In your drugs/medication pack you should have the following: Hydrogen peroxide to
wash and disinfect wounds, antibiotic ointment, individually wrapped alcohol swabs,
aspirin and non-aspirin tablets, Prescriptions and any long-term medications (keep these
current),diarrhea medicine, and eye drops. Other things you should have are some
dressings. Some suggestions for this subject are bandage strips, ace bandages, rolled
gauve, adehsive tape roll, and cotton swabs. There are other things you should use to
keep safe. If you want a list of these things you should use this website;
http://www.bt.cdc.gov/disasters/earthquakes/supplies.asp
Works Cited
Chapter 1
Tectonic Plate,
[www].http://www.crystalinks.com/tectonicplates.html. 6/5/08
Pacific Ring of Fire, [www]. http://www.crystalinks.com/rof.html. 6/5/08
Chapter 2
USGS, [www]. http://quake.usgs.gov/recenteqs/latest.htm. 6/5/08
Earthquake Map, [www]. http://www.crustal.ucsb.edu/scec/webquakes/.
6/5/08
Earthquakes for kids, [www]. http://earthquake.usgs.gov/4kids/ . 6/5/08
Chapter 3
1st question
Earthquake Hazards, [www]. http://www.geo.mtu.edu/UPSeis/hazards.html. 6/5/08
2nd question
Earthquakes, [www]. http://tremor.nmt.edu/faq/prepare.html. 6/5/08
3rd question
How to Prepare, [www]. http://www.72hours.org/earthquake.html . 6/5/08
4th question
Disasters, [www]. http://www.bt.cdc.gov/disasters/earthquakes/supplies.asp. 6/5/08