An earthquake preparedness drill is scheduled Thursday in classrooms and other places across Arizona.
The Arizona Geological Survey says nearly 81,000 school children are expected to participate in the drill billed as the "Great Arizona Shakeout."
People associated with universities, government offices, tribal communities, civic groups and businesses also will participate.
It's scheduled for 10:17 a.m. and will feature drills informing people how to prepare for and survive earthquakes.
The greatest immediate danger in most homes or buildings are flying or falling items such as ceiling tiles, furniture, pictures, mirrors and lights.
Experts suggest dropping to the ground, taking cover under a sturdy table or desk and holding on until the shaking stops.
Arizona is among at least 28 states participating in the event.