Every year about 120 strong earthquakes with magnitudes of 6 to
6.9 on the Richter scale shake different areas of the United States. But the highest
level of damage is from about 18 major earthquakes that happen
every year with magnitudes of 7 to 7.9 on the Richter scale.
Scientists continuously record
and locate the center of all earthquakes and are trying to find
a pattern that may help them to forecast earthquakes days in
Many different measuring devices
and equipments are used for this purpose.