A wider network of buoys and better computer models gave forecasters in Hawaii on Saturday a much better picture of the approaching tsunami than they would have had in the past, but they admit that their models were not refined enough to declare whether a full-scale evacuation was really needed.

When a magnitude 8.8 earthquake buckled the ocean floor off Chile on Saturday, there were concerns of a repeat of the 2004 disaster in which a giant earthquake off Indonesia generated a tsunami that killed thousands of people hours later in Sri Lanka and India.

In Hawaii, it was 8:34 p.m. Friday. The magnitude of an earthquake gives an expectation of the size of the resulting tsunami, and with an 8.8 magnitude, the scientists at the Pacific Tsunami Warning Center expected a dangerous tsunami.

Coastlines around the Pacific were put on alert, and the beaches in Hawaii were evacuated well in advance of the arrival of the tsunami. But the waves there turned out to be smaller than what was initially expected, causing little or no damage, pointing to the still incomplete knowledge in the art and science of tsunami forecasting.

Charles McCreery, the center’s director, said some early forecasts predicted that waves as high as eight feet could wash into parts of Hawaii.