A rumbling noise came across the intercom and students, teachers, and staff took cover under their desks as if the ground was really shaking.

This was the scene in dozens of schools and District offices as Granite took part in the annual Great Utah ShakeOut. But, why the hubbub?

According to the Utah Geological Survey, the largest earthquake expected along the Wasatch fault line is about magnitude 7.5. Earthquake hazards can occur miles from an epicenter (ground shaking and soil liquefaction can occur 100 miles away from the epicenter of a magnitude 7.5 earthquake).

Geological studies show that the last large earthquake on the Wasatch fault occurred about 600 years ago, and possibly as recent as 400 years ago. Given that large Wasatch fault earthquakes occurred, on average, every 350 years, the next “big one” may strike any time (although it may not happen in our lifetime).

What to do when shaking begins:

• Drop down onto your hands and knees, before the earthquake knocks you down.
• Cover your head and neck under a sturdy table or desk. If there is no shelter nearby, only then should you get down near an interior wall.
• Hold on to your shelter, or your head and neck, until the shaking stops

What NOT to do:

Do NOT get in a doorway. Doorways in modern houses and buildings are not safe places, and they will not protect from flying or falling objects.

Do NOT run outside. Trying to run outside is dangerous, as the ground is moving and you can easily fall or be injured by debris.

Do NOT get in the so-called “triangle of life.” A circulating email proposes an alternative plan to the long established “Drop, Cover and Hold On” advice. These recommendations are based on several wrong assumptions that have been refuted by safety experts. Read more