A volcano near Alaska’s largest city is showing new signs of unrest, with experts saying the likelihood of an eruption at Mount Spurr in the next few weeks or months has increased. The Alaska Volcano Observatory said Wednesday that it had measured during recent overflights “significantly elevated volcanic gas emissions,” and said signs indicated an eruption was likely, though not certain, in the weeks or months ahead. “We expect to see further increases in seismic activity, gas emissions and surface heating prior to an eruption, if one were to occur,” the observatory said in a statement.