Engineers inspected the Alaska pipeline to determine the extent of the damage Monday after one of the most powerful earthquakes ever recorded in the United States knocked out some of its supports and forced a shutdown in the flow of oil.

Sunday's magnitude-7.9 quake was so strong that it opened cracks 6 feet wide in roads and rocked boats on lakes as far away as Louisiana. However, only one minor injury was reported — a woman who broke her arm in a fall when she fled her home.

The pipeline, which carries crude from the North Slope oil fields, was shut down as a precaution, and Alyeska Pipeline Service Co. spokesman Mike Heatwole said Monday it was too soon to know when pumping would resume.

The giant conduit, about 60 miles from the quake's epicenter, was not ruptured, but some brackets were damaged, leaving sections of the 48-inch-diameter pipe suspended without support, officials said. Crews began work on temporary supports.

The oil flow can be stopped for maintenance or other reasons without affecting oil shipments because a reserve is stored in tanks at the ocean terminal in Valdez.

Oil analysts had little concern that the pipeline shutdown would dramatically affect supplies or prices.

"As far as affecting the world's oil markets, it would probably have to be knocked out a month or more," said Ed Silliere, vice president of risk management at Energy Merchant LLC in New York.

Aftershocks rattled the region Monday, one with a magnitude of 4.5, and seismologists said more could be expected for the next several days.

The quake was centered in a remote and sparsely populated area southeast of Denali National Park, 90 miles south of Fairbanks, but was felt throughout much of Alaska. It cracked highways and roads, triggered rock slides, shook houses and knocked over home fuel tanks.

"A charging brown bear I can handle. This scared the hell out of me," said Randy Schmoker of Porcupine Creek. He watched the ground ripple with a series of 8-inch waves. "They looked like ocean waves."

A 150-pound anvil slid 20 feet across the floor of Schmoker's metalworking shop.

State Transportation Department crews worked through the night to make temporary repairs to roads, some of which had gaps up to 8 feet deep and 6 feet wide.

In the New Orleans area more than 3,000 miles away from the epicenter, the quake made lakes ripple and sloshed water out of pools.

At Mandeville, La., Carol Barcia, 47, saw boats bouncing around and her own boat banged against its dock. "One poor guy across the canal from us fell off his sailboat," she said.

Houseboats were shaken from their moorings on Seattle's Lake Union, more than 1,400 miles south.

"This earthquake was shallow and the energy went directly into the surface and that is what causes these effects so far away," said Dale Grant, a geophysicist with U.S. Geological Survey's National Earthquake Information Center in Golden, Colo.

Seismologists estimate a 185-mile section of the Denali fault ruptured, slipping nearly 20 feet, said scientist Lucy Jones, of the U.S. Geological Survey's office in Pasadena, Calif. Researchers were planning to map the rupture from the air before it vanishes beneath winter snows.

The earthquake was the most severe in the United States since a 1906 quake destroyed San Francisco, Jones said. Larger earthquakes have hit Alaska since, but in each case the epicenter was offshore.

Sunday's quake is as close "as it's going to get in terms of analyzing what happened in 1906 — and will happen in the next big one," she said.