After 14,000-foot Mount Colima began spewing lava and ash near the central Pacific coast, scientists set up round-the-clock monitoring posts and authorities closed an airport.

The volcano put on its greatest seismic display in nearly 80 years on Wednesday, but Colima state spokesman Juan Ramon Negrete said the activity posed no immediate threat to nearby residents."The situation of the volcano is stable. It has not required evacuation," Negrete said by telephone from Colima, a city of 60,000 people that is 20 miles south of the volcano.

The danger of a major eruption subsided after a part of the volcanic cone and a menacing lava dome atop the peak partially collapsed, said Michael Sheridan, a geologist from the State University of New York at Buffalo.

Negrete said the international airport in Colima, about 50 miles from the coast and 280 miles west of Mexico City, was closed to prevent accidents that could be caused by dust being kicked up from the eruption.

He said civil protection services provided 20 city buses for emergency use by nearly 2,000 rural dwellers in eight tiny towns around the volcano.

But he said no one in the six-mile radius of the volcanic center has wanted to use them to leave. Most are longtime ranchers in the area and are undaunted by the volcano's occasional activity.

Civil protection teams provided masks to nearby residents to prevent respiratory problems that might be caused by volcanic dust and gas; they also trucked in drinking water to substitute for local sources, Negrete said.

But he said, tests showed that none of the gases emanating from the volcano was toxic and the water system in the area was not contaminated.