SEATTLE, Washington — Roughly every three seconds, the equivalent of a large dump truck load of lava — 10 cubic yards — oozes into the crater of Mount St. Helens, and with the molten rock comes a steady drumfire of small earthquakes. The unremitting pace, going on for 15 months now, is uncommon, said U.S. Geological Survey geologist Dave Sherrod. Experts say it is unclear what the activity signifies or how much longer it will continue. “One view of this eruption is that we’re at the end of the eruption that began in 1980,” Sherrod said. “If it hadn’t been so cataclysmic … it might instead have gone through 30 or 40 years of domebuilding and small explosions.” St. Helens’ violent May 18, 1980, eruption blasted 3.7 billion cubic yards of ash and debris off the top of the mountain. Fifty-seven people died in the blast, which left a gaping crater in place of the perfect, snowclad cone that had marked the original 9,677-foot peak known as “America’s Mount Fuji.” St. Helens — now 8,325 feet — rumbled for another six years, extruding 97 million cubic yards of lava onto the crater floor in a […]