About 1.5 million people annually gaze upon the sunken battleship USS Arizona in Pearl Harbor, examining the coral-encrusted armor and droplets of rising fuel oil for insight into the cataclysm that struck Hawaii — and the United States — 70 years ago on Dec. 7, 1941.

Those still entombed below have had to rely on their living comrades to explain and never let the public forget the violence and sacrifice of the surprise Japanese attack, which killed 1,177 men on the Arizona alone.

"It was just 13 minutes of hell," recalled Louis Conter, then a 20-year-old quartermaster who was on watch that morning.

Punctuating that terror was an armor-piercing bomb that penetrated the forward deck and ignited aviation fuel and the powder magazines for the Arizona’s 14-inch guns.

"When it blew up, why, the bow came about 30 feet out of the water," said Conter, now 90. "It settled straight down into the bay and everything from the main mast forward was on fire, instantly."

The survivors have faithfully commemorated America’s entry into World War II year after year, decade after decade, but after 70 years, there just aren’t enough alive anymore or in good enough health across the country to carry on that cause.

"World War II history is about to go into dramatic evolution as this generation passes," said Daniel Martinez, chief historian at the World War II Valor in the Pacific National Monument, which includes the Arizona Memorial.

Of just 334 Arizona survivors, only 18 — one Marine and 17 sailors — are still known to be alive.

Most are now in their 90s. The oldest Arizona survivor, Joseph Langdell, is 97.

Seven crew members from the sunken battleship are expected to attend this year’s commemoration, but there may be fewer.

For the first time, there will be no Japanese veterans from the war because they are too ill to travel, said Martinez.

The Pearl Harbor Survivors Association, founded in 1958 and chartered by Congress is 1985, will call it quits as an incorporated organization on Dec. 31.

"When you consider the age and health of the individual members who have assumed those responsibilities as chapter officers, district directors and the executive board, it’s something that they would feel better not having to do," said President William Muehleib, 89, who survived the attack on Hickam Field.

The survivors association is down to about 2,700 members from a high of about 28,000, Muehleib said.

The theme of this year’s commemoration — "The Enduring Legacy: Pearl Harbor 1941-2011" — reflects the tidal shift already under way.

"The generation of Pearl Harbor survivors, World War II veterans and homefront civilians are passing to the next generation the hope and promise to caretake and cherish those events that altered their lives and America’s history," the National Park Service, which maintains the Arizona Memorial, said in a statement.

The park service opened a much larger and more encompassing $56 million Pearl Harbor Visitor Center last year to tell the story of Dec. 7 and the war in the Pacific in greater detail than ever before.

But Martinez can’t predict to what degree the attack — at one time a rallying point to "Remember Pearl Harbor!" — will remain in the American consciousness.

"We’re now looking at the reality that the World War II generation is fading," Martinez said. "How will the story evolve? What will Pearl Harbor mean even 25 years from now?"

Conter, the former quartermaster, a Grass Valley, Calif., resident who came out for the 50th and 60th anniversaries of the Oahu attacks and has returned for each of the past five years, says he feels a sense of responsibility to his fallen shipmates.

"You’ve got 1,177 shipmates that didn’t get a chance like we did to come back home and get married and have children and grandchildren and great-grandchildren. We were just the lucky ones that came home," said Conter, one of the handful of Arizona survivors coming out this year.

On Dec. 7, Conter and others helped sailors who were still alive, some of them badly burned, get to boats and hospital care. He then helped fight the fire for two days.

Lauren Bruner, who also was on the Arizona and is coming out for the commemoration, still gets choked up when he talks about his returns to the memorial where so many of his friends died.

"It’s always important to me," said Bruner, 91, who lives in La Mirada, Calif.

Bruner was in an anti-aircraft position just above the admiral’s bridge when the flash of fire from the armor-piercing bomb blast seared everything in its path.

His clothes were burned off, and he had to climb hand over hand over a rope to get to the safety of an adjacent ship. He spent seven months in a hospital.

Seventy years later, he’s pragmatic about the Japanese actions.

"They had their job to do, we had our job to do," he said.

Six military sites on Oahu were attacked on the morning of Dec. 7, 1941, and 2,390 Americans were killed in what became America’s entry into World War II. More than 320 aircraft were damaged or destroyed, along with 21 ships.

Twenty-nine Japanese aircraft were lost and 55 airmen killed, along with nine who died in midget submarines.

As many as 3,500 people are expected for the Wednesday morning waterfront ceremony behind the Pearl Harbor Visitor Center — slightly down from the turnout of 3,700 last year, when the new visitor center debuted.

At 7:55 a.m., the time of the Japanese attack, a moment of silence will be observed. The destroyer USS Chung-Hoon will render honors, and the 199th and 19th Fighter Squadrons will perform a flyover in a "missing man" formation.

Mal Middlesworth, who as an 18-year-old Marine popped a hatch on the heavy cruiser San Francisco and saw a Japanese torpedo plane 30 feet off the water at Pearl Harbor, served throughout the Pacific and was a Pearl Harbor Survivors Association president, will be the keynote speaker.

Secretary of the Navy Ray Mabus and Interior Secretary Ken Salazar also will speak, and the ceremony will conclude with a "Walk of Honor" by more than 100 Pearl Harbor survivors and other World War II veterans.

As the number of Dec. 7 survivors dwindles, the number of family members coming out to Hawaii with them has swelled with the understanding that living history is passing into history books.

Conter chuckled a bit about his own entourage.

"It started out with my wife and I and son, and son-in-law and daughter, and then we ended up also with our granddaughter and her husband," Conter said last week. "Then we got a call the day before yesterday that our nephew — who is a retired colonel in the Marine Corps, F-18 pilot, and an American Airlines pilot now — and his family are coming out. So we’re going to have about 20 there from the family."

Seven decades after the Dec. 7 attacks, there is talk each year that "this will be the last visit to Pearl Harbor" by survivors — and for some, it is.

Nancy Nease, historian of the USS Arizona Reunion Association, who keeps in touch with some of the survivors, said the toll is clear.

"The general consensus is their health is failing and they are just not able to make this pilgrimage," Nease said. "And you are still going to hear, ‘This is the last year,’ and I’m telling you, with these Pearl Harbor survivors, the last year is going to be the last man standing."