ANCHORAGE, Alaska – A Alaskan A volcano that hasn’t erupted in more than 30 years is showing increasing signs of seismic life, although volcanologists still say that doesn’t mean an eruption is imminent.

Several small earthquakes were detected around Mt. Spurr last week, prompting the Alaska Volcano Observatory (AVO) to raise the volcanoThe alert level changes to “yellow” from basic green.

But so far there are no immediate signs of an eruption.

“AVO continues to closely monitor activity at Mount Spurr for signals that the volcano is approaching an eruption,” AVO wrote in its Thursday update.

Scientists say previous eruptions were preceded by increasing earthquake activity, ground deformation and around the summit lake if the magma moved closer to the surface.

A lava dome smokes on the north side of Mount Redoubt in Lake Clark National Park and Preserve, Alaska, Thursday, June 21, 2012.

“Therefore, it is very likely that if an eruption were to occur, it would be preceded by additional signals that would allow advance warning,” the AVO said.

Mount Spurr lies just over 75 miles west of Anchoring and broke out for the last time in the summer of 1992, according to the AVO – an eruption that ended 39 years of dormancy. This eruption was accompanied by many warnings.

Volcanologists use several tools, including seismometers, webcams, lightning networks and satellite data, to keep a close eye on the volcano.