BACKGROUND:
An earthquake's destructiveness depends on many
factors. In addition to the amount of energy released from the initial fault
rupture, the depth where the earthquake begins (the focus), the distance a
structure is located from the epicenter, local geological conditions, and
the design of buildings can all influence the amount of damage that takes
place.
The energy released by an earthquake travels through
the Earth as seismic waves. Seismic waves travel at different speeds,
depending on the material they move through, as well as the type of motion
they transmit. Seismic waves cause an oscillatory, sometimes violent
movement of the Earth's surface. Many of these waves make noise, because
they are at a high enough frequency that we can hear them. In addition some
animals can hear other seismically caused vibrations that are not audible to
humans. During an earthquake, noise is also caused by falling objects and
other ongoing destruction.
PROCEDURE:
- Explain to the class that they have been discussing earthquakes and
volcanoes for the last few weeks and now it is time to discuss the
hazards associated with earthquakes.
- Remind the students that earthquakes and volcanoes are natural events.
This lab attempts to get students thinking about the intensities of an
earthquake and what hazards may occur during a disaster.
- Explain that earthquakes make the ground shake as seismic waves travel
through the Earth. Explain that people can hear these sounds. Also
discuss sounds that are made when different things fall or break during
an earthquake. Point out items in the classroom. Students should imagine
the sounds that would occur if the objects fell or broke. Remind the
students that many times a severe earthquake will shut down electrical
power. In the dark, using one’s sense of hearing is very important.
- Instruct students to close their eyes or cover their heads. Make
different sounds and have them guess what fell or broke. Discuss as a
class their reactions to each sound. Show pictures of earthquake damage
that can found under "Slideshows" on our website (https://msnucleus.org/membership/slideshow.html)
and have the students simulate the sounds that may have occurred during
that instance in each picture.
- Describe different earthquake situations that may occur while students
are at school. Ask the students what action they would take in each of
the situations you describe. For example, while in the classroom a
rumbling sound is heard and the window panes begin to break - what do
you do? This could mean a very strong earthquake and students should
turn away from the glass and duck under their tables. There is never
"one" answer during an earthquake. Logic and reasoning must be
part of earthquake safety in assessing the situation. If you have a plan
at your individual school during an earthquake, discuss this with
students. You will alleviate many fears during an earthquake, if the
students have a sense of what to do in advance. If you live in an area
that has no earthquakes, many of these precautionary steps are also
valid in other disaster situations. Remember that this is a mobile
society and children may be visiting or moving to a state that does have
earthquake dangers.
