HONOLULU -- The Pacific Tsunami Warning Center said that Sunday's 6.6 earthquake was not strong enough to generate a destructive tsunami.

The center issued an alert 3 minutes after the quake happened, saying there was no threat from a tsunami.

If the quake had been a magnitude 7 it would have generated a destructive wave, scientists said.

"If you were anything like most people, it was shaking long enough that you started to get alarmed. Well, imagine that lasting two or three times longer, and much more severe. And that's the short of thing that would generate a tsunami," said Gerard Fryer of the Pacific Tsunami Warning Center.

If the earthquake had generated a tsunami, a wave would have hit the Waikoloa coastline in just six or seven minutes, scientists said. It would take the wave about 20 minutes to reach the south coast of Maui and 35 minutes to reach Oahu.

A scientist at the Pacific Tsunami Warning Center said he believed this was the largest earthquake in Hawaii since 1983.

The quake was followed by 53 aftershocks, according to the U.S. Geological Survey. Seven minutes after the first quake, an aftershock measuring 5.8 struck near the epicenter of the earthquake.