If This Had Been an Actual Tsunami ...

California’s first tsunami warning in more than a decade triggered an uneven response in coastal communities up and down the state, with some agencies rushing to evacuate beaches and others deciding not to warn the public at all.

On Wednesday, as officials assessed the way they had handled the emergency, there was general agreement that much more needed to be done.

“I don’t think all the agencies got an A-plus on their response,” said Los Angeles Councilwoman Janice Hahn, who has asked for a report on how emergency teams handled the tsunami warning. “We’re lucky we just had a trial run.”

The tsunami alert, issued by the National Weather Service after a 7.2 magnitude quake struck off the coast of Northern California on Tuesday night, trickled down to local emergency officials in inconsistent ways.

Many received teletype messages from the state, but in some cases local authorities got the notices just as the wave was projected to hit. Some officials said they learned about the alert by watching television or receiving calls from panicked residents who had heard about the alert on TV.

The warning, the highest possible alert from the federal government, prompted confusion at some police departments. In Santa Monica, officials thought it was “just informational, only a bulletin,” said Police Sgt. Jeff Wiles. Assuming that they would receive an update if the situation became more serious, city officials decided not to open their emergency operations center.

In Huntington Beach, the police watch commander on duty had trouble interpreting the bulletins and wasn’t sure whether a tsunami warning was actually in effect. “They were confusing to read through,” said Lt. Craig Junginger. “It talks about wind variables and knots and waves.”

The warning stated that communities along the Pacific Ocean from British Columbia to the Mexican border should brace for a possible tsunami and that people along the beach should move to higher ground. The message gave approximate times over several hours at which a tsunami, if triggered by the quake, would strike various spots along the California coast. The state subsequently sent out its own warnings.

But the warning system leaves it up to local agencies to decide what to do next. And there was a great range of responses.

In places such as San Diego, Newport Beach and Seal Beach, lifeguards and police officers raced to beaches to clear people off the sand. But they allowed people in homes and businesses along the beach to remain.

In many other cities, including Half Moon Bay -- south of San Francisco -- and Long Beach, officials decided to monitor the situation and not take any action at the beaches.

Lon Waxstein, commander in the Half Moon Bay Police Department, said he didn’t think there was reason for panic.

“People need to get a grip,” he said. “They are getting way, way worried on something that has only happened once in recent history to the whole continental United States. But we have floods, we have wildfires, we have plane crashes -- those happen more than a tsunami.”

The warnings originated from the West Coast and Alaska Tsunami Warning Center, a National Weather Service office in Palmer, Alaska.

Immediately after sensors in the Pacific Ocean picked up the quake at 7:51 p.m., the center’s “seismic processing software” determined that the shaking exceeded 3.0 on the Richter scale and paged the scientists at the center, said Laura Furgione, regional director for the weather service in Alaska.

The message told the scientists that there was an earthquake 90 miles off Eureka and the preliminary magnitude was 7.4.

Scientists sent out an alert at 7:56 p.m.

The message appeared immediately on national weather websites, was wired to media outlets, went by satellite to emergency managers’ computers and was broadcast by speaker phone on a network developed for homeland security.

Policy dictates a warning if the underwater earthquake is 7.0 or stronger, a threshold based on historical tsunami data, Furgione said.

There was no time to debate whether a warning was necessary, she said, because the center’s projections showed that a wave could hit Crescent City within 40 minutes of the temblor and reach San Francisco about 50 minutes later.

“We don’t have time not to issue the warning,” she said. “It’s better to get the information out to the public and to the emergency managers so they can put an evacuation mechanism in place,” she said.

The 24-hour warning center at California’s Office of Emergency Services received the message on its computer at 7:57 p.m., said spokesman Eric Lamoureux.

Staff members posted the notice on their website and forwarded a teletype message to local agencies on the Law Enforcement Telecommunication System. An automated phone message went out to all California coastal counties. Staff members then called each of those counties to confirm that they had received the message.

Lamoureux said all of this took approximately 7 minutes.

The public first learned about the alert a few minutes later, when several broadcasters flashed alerts. Cable provider Comcast broke into all programming to issue a warning about a possible tsunami. But the Los Angeles County Sheriff’s Department chose not to send a local bulletin to broadcasters after concluding that the threat was not great enough, said Sgt. Britta Tubbs of the emergency operations bureau.

Despite the warnings, local officials said they would have been hard pressed to launch an effective evacuation had a tsunami formed.

Arcata, a small city at the north end of Humboldt Bay, received a tsunami warning at 8:03 p.m. Officials saw that the tsunami was projected to hit Crescent City in the next 30 minutes and assumed the wave could crash into their community minutes later.

“Had the tsunami been generated last night, we would not have had enough time to generate evacuation for that local event,” said Tom Chapman, a captain at the Arcata Police Department. “While the system really helps us, time constraints, which the system has no control over, really can play a factor in the response we can generate.”

As soon as Seal Beach police officers saw the warning, they began putting together a reverse 911 phone tree that would have sent a recorded message to more than 800 homes in the flood-prone areas. The message would have advised residents in low-lying areas to head for higher ground.

But it takes about an hour for the message to be recorded, input into the computer and sent out -- so it’s unclear whether the phone alerts would have been completed in time.

“We had started to put it together, but then the warning was canceled,” said Sgt. Rick Ransdell with the Seal Beach Police Department.

Fort Bragg officials said emergency workers struggled with a deluge of calls from concerned residents after hearing reports on the radio and television or from patrol cars that broadcast the warning from their public address systems.

As residents heard about the tsunami news, many called 911 to ask for advice on what to do. The lines became so jammed that Mendocino County officials called a local radio station to tell people to stop calling 911, said Lt. Floyd Higdon of the Fort Bragg Police Department.

After last December’s tsunami off the coast of Sumatra that killed more than 175,000 people, “everyone has taken this as a serious issue,” Higdon said.

By about 8:23 p.m., officials at the tsunami center in Alaska were getting the first indications that the quake might not produce a tsunami. A shoreline gauge at Humboldt Bay near Eureka reported that the water level had not changed.

About 20 minutes later, a deep ocean buoy near the epicenter picked up a 1-centimeter wave. This reaffirmed to scientists that a major tsunami would not occur.

It took 58 minutes to confirm there was no tsunami, Furgione said. Then, at 9:09 p.m., the federal warning center sent out a message canceling the alert.

Federal and state officials said they were satisfied with their efforts to spread the word. Lamoureux, the state official, said that some state emergency officials outside of the warning center had trouble reaching some of the local agencies.

Some of them had to wait for several minutes because the lines were busy with calls from residents.

But local officials acknowledge they have much work to do.

Larry Collins, the Los Angeles County Fire Department captain on the county’s tsunami task force, said officials want to install street signs in coastal areas detailing evacuation routes and install air raid sirens that would warn of a massive wave. They are also telling beachside residents to take their own steps to guard their safety, such as buying special radios that broadcast national weather alerts.

“We don’t have a consistent plan statewide or even countywide,” Collins said.

“Right now, some places evacuate and others don’t. Each city makes their own rules, and there’s no governing body that says, ‘You will operate consistently like this,’ ” he added. “The best warning for people in vulnerable coastal areas is that if they feel a strong shaking, they need to evacuate now, without any warning.”

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Times staff writers Sara Lin, Wendy Lee and Jessica Gresko contributed to this report.

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(BEGIN TEXT OF INFOBOX)

The tsunami threat

Tuesday’s quake, which triggered California’s first tsunami warning in a decade, occurred near the Cascadia subduction zone, which is capable of triggering big tsunamis like the one in December near Sumatra. But this one involved a different kind of fault. Here’s a look at the plate dynamics, and the warning system:

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Movement of segments, or tectonic plates, of the Earth’s crust

Strike-slip fault:

Off much of Northern California, plates move horizontally past each other. Tuesday’s quake did not change the level of the ocean floor.

Subduction fault: Off Sumatra, one plate pushes under another. An undersea quake on Dec. 26 lifted the upper plate, causing a tsunami.

High-tech tracking

Tsunami warning centers in the U.S. depend on seismometers to measure earthquake intensity, and sensors on the Pacific Ocean floor, to detect tsunamis.

1. Bottom pressure re-corders (BPR) detect tsunamis and trans-mit data to a buoy.

2. Satellite relays buoy data to ground stations.

3. Deciphered signals are sent to the Tsunami Warning Centers in Alaska and Hawaii.

Warning centers issue bulletins to local, state, national and international outlets and media.

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Getting out the word

The California Office of Emergency Services notified all coastal counties about the tsunami hazard within 15 minutes of the earthquake and within eight minutes of the Alaska Tsunami Warning Center’s notification:

7:51 p.m.: Earthquake occurs

7:53 p.m.: California Integrated Seismic Network receives direct notification of earthquake.

Starting at 7:57 p.m.: California Integrated Seismic Network posts tsunami warning. Alaska Tsunami Center conveys tsunami warning to the Office of Emergency Service office in Sacramento, which then disseminates it via:

The California Law Enforcement Teletype System

The California Alert and Warning System to all 58 counties, mostly to sheriff’s offices.

The California Emergency Digital Information System, a subscription service for emergency managers and internet users.

Individual phone calls by OES personnel to each coastal county to discuss the warning.

8:04 p.m.: Notification of warning is completed.

9:09 p.m.: Procedures are repeated for bulletin canceling the tsunami warning.

9:11 p.m.: Cancellation notification process is completed.

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Sources: California Office of Emergency Services; The Kingfisher Visual Factfinder; National Oceanic and Atmospheric Administration; International Tsunami Information Center; Graphics reporting by Julie Sheer and Cheryl Brownstein-Santiago

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Tsunami alert

Highlights from a warning issued Tuesday evening by the West Coast and Alaska Tsunami Warning Center:

* A tsunami warning is in effect for the coastal areas from the California-Mexico border to the north tip of Vancouver.

* It is not known -- repeat not known -- if a tsunami exists, but a tsunami may have been generated.

* Therefore persons in low-lying coastal areas should be alert to instructions from their local emergency officials.

* Persons on the beach should move to higher ground if in a warned area. Tsunamis may be a series of waves, which could be dangerous for several hours after the initial wave arrival.

Los Angeles Times