WASHINGTON • As strange, serious and scary as the erroneous emergency notification about a missile attack against Hawaii may have been, it was far from the first such false alarm the United States has faced. Here is a look at a few other cases.

OCT 5, 1960

A false alarm occurred when an early warning radar in Greenland reported to the North American Air Defence Command (Norad) headquarters that it had detected dozens of inbound Soviet missiles.

The report thrust Norad to its maximum alert level, according to the Union of Concerned Scientists, but officials later determined that the radar had been fooled by the "moonrise over Norway".

NOV 9, 1979

Computers at Norad indicated that the United States was under attack by missiles launched by a Soviet submarine.

Ten jet interceptors from three bases in the US and Canada were scrambled, and missile bases went on "lowlevel alert", The New York Times (NYT) reported.

When satellite data did not confirm an attack after six minutes, officials decided that no immediate action was necessary. Investigations later discovered that a "war game" tape had been loaded into the Norad computer as part of a test. A technician mistakenly inserted it into the computer.

"The tape simulated a missile attack on North America, and by mechanical error, that information was transmitted into the highly sensitive early warning system, which read it as a 'live launch' and thus initiated a sequence of events to determine whether the US was actually under attack," NYT said.

JUNE 3, 1980

Less than a year later, computers once again issued a warning about a nuclear attack.

Bomber and tanker crews were ordered to their stations, the National Emergency Airborne Command Post taxied into position and the Federal Aviation Administration prepared to order every airborne commercial airliner to land, according to the Union of Concerned Scientists and The New Yorker.

President Jimmy Carter's national security adviser Zbigniew Brzezinski got a call telling him 2,200 missiles were heading towards the US. Then, Mr Brzezinski got another call: It had been a false alarm.

An investigation found that a defective computer chip - costing 46 US cents - was to blame.

SEPT 26, 1983

Lieutenant-Colonel Stanislav Petrov, 44 , from the Soviet Air Defence Forces, was the duty officer at a secret command centre outside Moscow when the alarms went off.

Computers warned that five missiles had been launched from a US base. "For 15 seconds, we were in a state of shock," he later told The Washington Post in an interview.

Electronic maps and screens were flashing as he tried to absorb streams of information. His training and intuition told him a first strike by the US would come in an overwhelming onslaught, not "only five missiles", he told the paper.

After five nerve-wracking minutes, he decided the reports were probably a false alarm. And they were. The satellite had mistaken the sun's reflection off the tops of clouds for a missile launch.

AUG 11, 1984

Preparing for his regular Saturday afternoon radio broadcast, President Ronald Reagan quipped before a live microphone that he had "signed legislation that will outlaw Russia forever" and that "we begin bombing in five minutes".

Months later, NYT reported that two days after Mr Reagan's joke, a low-level Soviet military official "ordered an alert of troops in the Far East". The alert was said to have been cancelled about 30 minutes later by a higher authority. US intelligence officials contended the alert was "a non-event".

NYTIMES