On the 23rd anniversary of the Loma Prieta earthquake that rattled the San Francisco region, local and national emergency and public safety officials came together to urge the public to register for Thursday's Great California ShakeOut.

The Shakeout, held at 10:18 a.m. on the 18th day of the tenth month, is an earthquake drill for everyone to practice how to "drop, cover and hold on" when a temblor strikes.

More than nine million state residents, and even some outside of California, are expected to participate, including those at working at offices, traveling on public transit or attending school or staying at home.

A collaboration between various city, state and federal agencies and nonprofit groups and other entities, today's noon news conference and information fair with San Francisco fire Chief Joanne Hayes-White and BART board president John McPartland in attendance at San Francisco's Union Square emphasized preparedness and safety before and after an earthquake.

Nancy Ward with the Federal Emergency Management Agency said the shakeout encourages preparedness and general readiness and "it works."

She urged residents to practice crouching under a sturdy surface and covering their necks while holding onto something, especially since an earthquake can strike at any time.

About 10 booths with representatives from the nonprofit Earthquake Country Alliance, FEMA, the California Emergency Management Agency, Red Cross, and the city's NERT, or Neighborhood Emergency Response Team program, and others lined the square's western edge this afternoon and offered citizens a chance to learn about earthquake science, preparation, safety and an opportunity to sign up for the ShakeOut.

Stephen Sellers with the California Emergency Management Agency said, "we need to be ready" and called on all residents to be prepared, but also ready to help those incapable of helping themselves.

"We're all in this together," he said.

Since the 1989 quake in which 63 died and nearly 4,000 were injured, city officials have geared up for the next large-scale temblor looming ahead with various agencies, and even have established private partnerships including with Bank of America and Wells Fargo.

"We are so fortunate to be in the Bay Area where collaboration is not a foreign concept," Harold Brook, CEO of Red Cross Bay Area, said.

A "flash drill" then broke out on the square with Red Cross volunteers and employees dancing to an earthquake-themed soundtrack, which included Bill Haley's "Shake, Rattle and Roll" and a demonstration on how to drop, cover and hold on.

A Congo line then formed, which Hayes-White joined at the front that led to the ShakeOut sign-up booth.

Participating ShakeOut locations in the Bay Area Thursday include area Target stores, the California Academy of Sciences in San Francisco's Golden Gate Park, San Jose's Tech Museum and at San Francisco's Bayview District school Dr. Charles Drew Elementary School.

San Francisco Mayor Ed Lee, Hayes-White and the city's Emergency Management Deputy Director Rob Dudgeon will put their training to the test with students in a classroom at the school located at 50 Pomona Ave. in San Francisco.

BART is also observing the day to remind riders that a quake could strike while riding the system.

For more information about the ShakeOut visit www.shakeout.org.