Let’s be better prepared next time. The Washington region should use Tuesday’s earthquake as a teachable moment so residents and authorities alike have a clearer idea in advance how to react when the ground starts to shake.

We didn’t do so well on this occasion. From K Street to Anacostia, Washingtonians just didn’t know what to do.

“We panicked because we didn’t get any alarm. We didn’t know what was going on,” Brenda Walters, 44, of Northeast said of the U.S. Census office where she works. “There is an evacuation plan, but nobody stuck to it. Everybody just went their own way. We knew to take the stairs, and that’s about it.”

Although blasé former Californians proclaimed us wimps for supposedly panicking, many of us had urgent, valid questions: Leave a building right away, or hide in a doorway? How long before it’s safe to go back inside? Is it okay to use Metro to get home?

Imagine how much worse it could have been. Had it been a major quake instead of “just” 5.8, our ignorance could have caused serious chaos, and cost injuries and lives.

There’s really not much excuse for this. As the nation’s capital, with the memory still strong of the Sept. 11 attacks, we ought to be the world champions of emergency preparedness.

Instead, a moderate snowstorm — which we get almost every year — can paralyze us. It’s little surprise that an earthquake would baffle us.

An earthquake “is not an everyday occurrence, so it seems like Washington doesn’t know what to do,” Bev Ellison, 49, a law firm secretary, said as she stood in McPherson Square. She was waiting to see if her office was going to reopen for the day after the evacuation.

“We were trying to get in touch with Californians, because it’s typical [for them],” she said. “After this, I’m sure we’ll have leaflets and pamphlets instructing us.”

There’s an idea!

In many cases, authorities provided little or no help. That annoyed Metro passengers packed eight ranks deep at L’Enfant Plaza station at 3:45 p.m., or just shy of two hours after the shock.

The crowd grew unruly as packed trains passed through with little or no space for new riders. Announcements were few and barely audible.

“What’s Metro going to do, shuffle us around like sheep? You get no information at all,” Barry Strong, 42, said. Spotting no Metro security personnel nearby, he added, “I’d expect to see more Metro employees at least trying to restore order.”

On the bright side, the foul mood didn’t last long. The crowd cheered when an empty train arrived a few minutes later.

In Anacostia, several parents and grandparents whom I interviewed expressed worry that schools were slow to evacuate after the quake.

“A lot of people were taking their time getting out,” Kevin A. Thomas, 44, a car wash employee, said. “These buildings over here are old. If we get another one, they could come right down.”

Of course, some people had plans in place. William Wade, 28, a musician in Anacostia who used to live in California, grabbed what he called his “emergency bag” and left the house as soon as he felt the quake. The red canvas sack contains bottled water, cans of tuna, a flashlight and a compass, among other necessities.

“Most people have to scramble for what they need. Being married, I think it’s important for the family to be prepared,” Wade said.

There’s a model for the whole region to follow.