U.S. Geological Survey scientists continued to say no major eruption was imminent - just a continuation of the minor ash and steam eruptions that have been occurring since the mountain re-awakened this fall.

Saturday's earthquake appeared to be a larger version of the small earthquakes that have been occurring about once a minute for the past several weeks, the USGS said in a news release.

Scientists hoped to take advantage of good weather predicted for Sunday and Monday to get a better look at the volcano.

Mount St. Helens blew apart in May 1980, killing 57 people and covering the region with gritty ash. The eruption took off the top 1,313 feet of the peak.

The mountain, about 100 miles south of Seattle, reawakened in late September with a flurry of small earthquakes ranging up to magnitude 3.2, then let off a burst of steam and ash Oct. 1 - the first in a series of small eruptions.

Scientists noticed the first fresh lava on the crater's surface about a week and a half later. Since then, lava has been pouring onto the crater floor from superheated magma far below at a rate of up to a dump truck load per second. The new dome and the uplifted floor beneath it now cover 70 acres and stand 750 feet high.