Page 109 - Active Science 5 Ebook and Activity

E arthquake Plate movement

Sudden shaking of the earth’s surface Epicentre
is termed as an earthquake. The
earthquakes occur along the weak lines
when the plates slide and collide with each

other. The deep point inside the earth from
where earthquake starts is called focus
and the point above the focus is called

epicentre.

After Earthquake

The area most affected by an earthquake Focus Seismic waves
is the epicentre. As we move away from
the epicentre, the effects goes on reducing.

Some common effects are:

1. Damage to man–made structures, trees, roads and vehicles

2. Flooding and fires
3. Injuries and deaths

4. Spilling of hazardous chemicals

Scaling Earthquakes and Their Effects
Earthquakes are recorded, detected and measured by an instrument called seismograph.

The strength of the earthquake is expressed in two ways – magnitude and intensity.
Magnitude is expressed in whole numbers and intensity in Roman numerals. The Richter
scale is a standard scale which is used to find out the intensity of an earthquake. If there
is a earthquake measuring 3, 4 or 5 on the scale, it means there will be some damage to

property. If it is 6 or more, then there will be a huge damage even causing deaths.

Do You Know?
The largest recorded
earthquake in the world was
of magnitude of 9.5 in Chile

on May 22, 1960.

Precautions Taken During An Earthquake
There are some ways in which you can keep yourself safe at the time of an earthquake.

1. Do not panic, stay calm!

2. If you are on the top floor, do not use elevator, use a staircase.

109
Active Science-5