Updated

Relatives and friends of those lost aboard Alaska Airlines Flight 261 joined together Saturday for a service remembering their loved ones.

Prior to the memorial at Pepperdine University, which overlooks the Pacific in Malibu, dozens of surfers, holding hands, paddled out into the chilly Pacific waters and left three flower wreaths near the site of last week's crash.

The surfers, who had no connection to the victims, formed a circle and held hands while sitting on their boards. Three of them them, carrying the wreaths, moved to the middle of the circle and let them go.

As they did, a pod of dolphins jumped 50 yards away.

"What better place to be, to rest in peace," said Keith Akins, a member of the Ventura Surf Club.

At the memorial service later that evening, 88 white doves — one for each victim of Alaska Airlines Flight 261 — were released into the California sky.

"All of California aches with you," Gov. Gray Davis told the mourners gathered at the fieldhouse on Pepperdine University's oceanside campus. "The men and women aboard Flight 261 were our friends, our families, our neighbors."

Rabbi Aaron Kriegel, one of six clergy members who spoke during the service, told mourners: "We want you to know there is a tomorrow. Life will go on. ... We are stronger because they lived."

Nearly 1,000 people crowded the fieldhouse for the private service for the victims' family and friends. Their silence through the 40-minute service was broken occasionally by sobs. Eighty-eight white candles lined the front of the fieldhouse during the service.

As the mourners filed out of the fieldhouse, many embraced and tossed white roses into baskets. The roses were to be taken by helicopter to the crash site and scattered over the water.

On Sunday, the Coast Guard planned to drop flowers from the service over the crash site, a few miles to the northwest.

About 200 relatives and friends of the crash victims have been staying in hotels in Ventura County and Los Angeles, keeping a close eye on the investigation and participating in several memorial events, including a beachfront vigil and a boat trip to the accident site.

Meanwhile, investigators trying to determine the cause of the crash are focusing on two noises about 10 minutes apart, which were loud enough to be heard in the cockpit.

Officials aren't speculating about the noises, heard on the plane's cockpit voice recorder before Flight 261 plunged into the Pacific, killing all 88 people aboard.

But an aviation safety expert not connected to the probe said they are consistent with a deteriorating problem in the plane's tail, where pilots had reported a problem with the stabilizer — the wide part of the tail that keeps the plane level.

"It sounds like something failed in the tail, and it certainly would account for a jammed stabilizer," William Waldock, associate director for the Center for Aerospace Safety Education at Embry-Riddle Aeronautical University, said Friday.

But he cautioned that it is impossible to diagnose the noises without a better description than what has been provided so far.

The first bang, about 12 minutes before the end of the recording, was so loud a flight attendant came to the cockpit to report it, and was told by pilots that they also heard the sound.

About 10 minutes later, a second loud noise is heard, "and the airplane appears to go out of control," said John Hammerschmidt of the National Transportation Safety Board.

Witnesses who saw the plane go down Monday said it flipped upside down and spiraled straight into the ocean near Port Hueneme, Calif. All 88 people aboard the flight — bound for San Francisco and Seattle from Puerto Vallarta, Mexico — were killed.

Salvage Effort Continues 

Also Saturday, investigators were to continue mapping the crash site. Hammerschmidt said that stage of the investigation was progressing rapidly, with a Navy vessel using side-scan sonar to track the debris in the Santa Barbara Channel, about 10 miles from shore.

Sonar appeared to show the debris in a single concentration within an area the size of a football field, he said.

A video taken by a remote-operated underwater robot indicated most of the wreckage consisted of pieces about 5 or 6 feet long, but there was a section of fuselage estimated to be 10 feet long.

The robot also has sent up video of the plane's tail and a 5-foot section of the leading edge of the 40-foot long horizontal stabilizer.

After the crash site is mapped, robots like the one that salvaged the plane's flight recorders earlier this week will eventually be sent down to help retrieve bodies.

"You can't do it overnight," said Navy Capt. Terry Labrecque. "You have to be methodical."

Four bodies have been recovered so far, and authorities believe more may be trapped beneath debris 650 feet underwater.

Piecing Together the Details 

Investigators hope to determine whether pilot error may have triggered the tragedy.

Officials have said the cockpit crew had requested an emergency landing at Los Angeles International Airport, saying that the plane's stabilizer trim had jammed. In a conversation with an Alaska Airlines maintenance crew, the pilots asked if there was a "hidden circuit breaker" in the stabilizer mechanism, leading to speculation that the crew might have deactivated a circuit breaker.

The pilots were told there was no hidden circuit breaker.

The plane's voice recorder shows that for at least 30 minutes before the crash the pilots were struggling to correct a problem with the tailwing stabilizer, which they reported had jammed.

About 12 minutes before the end of the recording the plane apparently lost vertical control, Hammerschmidt said.

The crew recovered control about 90 seconds later. Shortly after, a flight attendant is heard telling the pilots of a loud noise from the rear of the jet, and "the crew acknowledged that they had heard it too," Hammerschmidt said.

The second noise, actually recorded by the device, sounded just near the end of the tape.

The plane has an audible alarm to indicate a stall, or dangerous loss of lift, but no such warning is heard on the tape, Hammerschmidt said.

According to the Los Angeles Times, the head of the Los Angeles chapter of the National Air Traffic Controllers Association described the captain and co-captain of the flight, Ted Thompson and William Tansky, as "heroes," who had "acted in an extremely professional manner."

"It was an extremely courageous move to stay over water and not endanger more lives over land with an aircraft that could not be controlled," Hamid Ghaffari added in a letter to the families of the crash victims.

The Associated Press and Reuters contributed to this report