We All Have Our Faults
Earthquakes are powerful movements
of the earth. They can be small, only a quiver or shudder. Or they can be
quite large and harmful. What exactly is an earthquake and why in the world
does the earth move so much? 
The earth's crust is separated into enormous plates that are constantly
moving. All of our continents and oceans ride on these thick plates as they
crash together, move apart or slide by each other. The area where the plates
meet is called a fault line. Because the earth is constantly expanding,
the currents of molten rock underneath the plates build up pressure which
is released through slight shifts.| DID YOU KNOW? The earth's crust is made up of over a dozen large and small tectonic plates. They move between one and eight inches a year. |
Plates rubbing together
on fault lines cause earthquakes. The biggest earthquakes occur at the plates'
edges. An instrument called a seismograph records the earth's movements.| FUN FACT: The first seismograph was invented in 136 AD in China. It was a copper bowl with dragon heads all around the edge. Each dragon's mouth held a ball. Below the dragons were open-mouthed frogs. During an earthquake, a ball would drop from a dragon into a frog's mouth. That's how they'd know the direction of the earth's movement. |
Right this minute, there's probably an earthquake happening somewhere in the world. The good news is that most are very small, so small we don't notice them. But a few are so violent that they can collapse buildings, break gas and plumbing pipes, and trigger events that start fires and landslides. Earthquakes in the ocean can cause giant waves called tsunamis to roll inland and destroy coastal property.
ROCK & ROLL ZONES
The areas in the world that are on or near fault lines have more earthquakes. The people that live in earthquake zones need to know what to do in case of an earthquake. Do you live in an area that has earthquakes? If you do, it's important that you and your family are prepared. Here's some things that you should know:
- If you are outdoors and begin to experience an earthquake, move to
an open area away from trees, power lines and tall structures.
- If you are inside, drop down to the floor. Take cover beneath a sturdy
object such as a desk, table, or strong door frame. Then, grab onto
the desk or table legs, or brace the door frame, and be prepared to
move with it.
- It is important to be prepared and know how to protect yourself during
an earthquake.
Books:
James, Ian. Planet Earth, (Great Britain, Dempsey Parr, 1998).
Steele, Philip. Rocking and Rolling, (Massachusetts: Candlewick Press, 1997).
Websites:
Visit the Cal Tech Seismological Lab at:
http://www.gps.caltech.edu/~polet/recofd.html
Check out the earth's plates on This Dynamic Earth at:
http://pubs.usgs.gov/publications/text/dynamic.html