Six low-intensity earthquakes rumbled beneath Mount Adams during September, according to the U.S. Geological Survey Cascades Volcano Observatory. That’s an unusual amount of seismic activity at the 12,276-foot volcano in southwest Washington, marking the most earthquakes at the mountain in a month since monitoring began there in 1982. Even so, officials say there’s no imminent eruption threat. Mount Adams last erupted between 3,800 and 7,600 years ago.