Earthquakes are caused when rocks which are underground suddenly breaks .The sudden release of energy causes the waves that makes the ground shake . When two plates are rubbing against each other. They don't just slide smoothly the rocks catches each other . After a while the rocks breaks because of the pressure. Earthquakes can be" deadly at all times. The strongest/earthquake happened in the Indian ocean it killed over 266,189 people it caused lots of destruction/damage.
•southern California area has about 10,000 earthquakes. •earthquake waves have a frequency of less than 20 Hz. •soft ground shakes more than hard rock in an earthquake. • In 1663 the European settlers experienced their first earthquake in America.