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  • Look out! Earthquake!

  • What should you do during a big tremor?

  • This is Dan.

  • He recently arrived in this country to start a job.

  • Suddenly, his office starts to shake and the building sways violently.

  • Dan is from a country that doesn't have earthquakes, and he panics.

  • Luckily, his coworker Rena is there to show him what to do.

  • First, get under a desk for protection.

  • If there's time, open a door to secure an exit.

  • In a high rise building, tremors could continue for ten minutes, or more.

  • Although the shaking may make you feel sick, the building is unlikely to collapse, so stay calm.

  • Dan is impressed by how cool Rina is, but he wonders why high rise buildings sway with such long movements.

  • Rena explains.

  • The shaking movement due to an earthquake, is called seismic ground motion.

  • The number of seconds for each back and forth movement is its period.

  • Depending on the length of the period, the movement is either short or long period ground motion.

  • The thicker the ground's sedimentary layers, the longer the period.

  • Because cities usually built on planes composed of very thick sedimentary layers, they often experience long period ground motion.

  • Each building has it's own period, which depends on the type of construction and height.

  • Higher buildings have longer periods, and these are more likely to be the same as the ground motion.

  • When a building's period is the same as that of the ground, this causes resonance, which greatly magnifies the shaking.

  • That's why, even though the ground outside is only moving slightly, a tall building might be shaking violently.

  • Dan now understands what's happening.

  • The only reason desks and lockers don't move is that they are all securely fastened down.

  • After the shaking stops, Dan asks Rena to lunch.

  • "Not so fast." says Rena.

  • Don't assume it's safe to go outside so quickly.

  • If you're near the sea or a river, a tsunami might be coming.

  • And after a major tremor, aftershocks make it dangerous to be near damaged structures, older buildings or cliffs that might collapse.

  • Rena tells Dan he should train to be ready for an earthquake.

  • In earthquake prone countries, communities hold disaster drills, and many facilities provide earthquake simulations.

  • The latest facilities can simulate earthquakes in high rise buildings and many other scenarios.

  • To find out what's available in your area, just look online.

  • Thanks to Rena, Dan is now ready for life in an earthquake zone.

  • The next weekend, he takes his family to an earthquake simulator.

  • Now they'll know exactly what to do in a big quake.

  • To stay safe during a major earthquake, the most important thing is knowledge.

  • Official online disaster mitigation sites provide all the information you need.

  • Remember, don't rush, stay calm, and help others.

Look out! Earthquake!

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