How can earthquakes be predicted?

• How can earthquakes be predicted?

  They can't reliably be predicted but some signs may indicate an earthquake is likely
• What can lasers do?

  Detect movements of plates before the quake
• How are vibrations in the Earths crust monitored?

  Using seismometers (if they increase there might be an earthquake coming)
• How can gases be measured?

  They escape from the crust just before the quake
• Why will rocks crack and expand?

  Increases pressure