The ongoing swarm at Yellowstone National Park is now one of the longest and largest on record. The largest swarm ever recorded was in October 1985; it lasted for three months and included more than 3,000 earthquakes. There was another large swarm in 2010, when more than 2,000 events were recorded over a month. ... As of August 30, 2,357 earthquakes had been recorded. The most powerful in recent weeks was magnitude 3.3; it took place on August 21. The most powerful in the current swarm was a magnitude 4.4, which was recorded on June 15. Yellowstone has had dozens...