A Japanese submarine drew up to the California coast and shelled an oil field 50 years ago Sunday. It was a pinprick of an attack, but unnerving for a nation newly and reluctantly drawn into World War II.

On its face, the shelling of Ellwood beach Feb. 23, 1942, was not a major event of the war. It injured no one and did a mere $500 damage to a shed and catwalk belonging to the Barnsdall-Rio Grande Oil Co.Yet for a country reeling from the attack on Pearl Harbor just two months before, the volley of 5-inch shells confirmed widespread fears that Japan could wage war on American soil. It was, after all, the first enemy attack on U.S. shores since the War of 1812.

The assault also hastened the roundup of 120,000 Japanese-Americans in internment camps for the war's duration, a move Franklin D. Roosevelt authorized just four days earlier.

J.J. Hollister III was 10, but he remembers it well. The family radio was tuned in for one of Roosevelt's fireside chats, when the boy was startled by the thunder of a distant cannon.

"In a moment or two we heard a whistling noise and a thump as a projectile hit near the house," Hollister recalled.

The family scrambled outside their canyon home and peered through the dusk's dimming light at the Pacific Ocean. Bright flashes lit up an oil field on the shore. After the flashes came "an eerie whistling and caterwauling," Hollister said. "It was a sickening sound."

In an adjacent canyon on the rural stretch of coastline about 100 miles northwest of Los Angeles, Ruth Pratt was tending her garden. Her husband, John, was on Home Guard duty 10 miles away in Santa Barbara.

"I thought something was going wrong at the refinery," Ruth Pratt said. "Then there was something like a whizzing sound coming right at me."

Early the next morning, the Hollisters, Pratt and their neighbors learned the cause of the mysterious blasts in a radio news bulletin: a Japanese submarine had shelled the Ellwood oil field.

More assaults, all minor, followed: a Japanese submarine fired at the Oregon coast; a Japanese pilot bombed Oregon forests to no effect; the Japanese exploded balloon bombs in the Northwest.

But for Americans living there and then, it felt like extreme peril.

Spy scares raged throughout Southern California. An "Avenge Ellwood" campaign helped sell war bonds.

Fear of a major Japanese assault may have contributed to the so-called Battle of Los Angeles early on Feb. 25, when anti-aircraft batteries fired blindly at an unidentified object reported heading south over Santa Monica Bay.

The Ellwood attack fostered its own myths. One claimed the U.S. Navy staged the event to excite war fever.

Witnesses also reported that during the attack, someone signaled the submarine from the ridge of Winchester Canyon, perhaps directing its fire.

Hollister believes the winking lights may have come from the headlamps of his father's car as it bumped along a high dirt road where the elder man hoped to get a better look.

"It's like `JFK.' The deeper you dig, the more wild rumors you're going to find," said Barney Brantingham, a Santa Barbara News-Press columnist who has written about the attack. "The question that came up was, `Why here?' "

Nobukiyo Nambu, a lieutenant on the Japanese sub, offered an answer in a 1963 interview: Quite by accident.

Nambu said the 384-foot sub and its crew of 70 pursued a U.S. task force from the Marshall Islands eastward and arrived off San Diego on Feb. 20.

Ordered to attack a coastal target and divert U.S. warships northward, the sub headed to San Francisco. Shooting into that city wasn't feasible, so the sub swung south, surfacing 1,500 yards off Ellwood about 7 p.m. Feb. 23. Five sailors scrambled onto the deck and manned the gun.