That rumbling you feel is not necessarily a passing subway. New York City and the surrounding region gets a surprising number of small earthquakes, and a 2008 study from the region’s network of seismographs, run by Lamont-Doherty Earth Observatory, suggests that the risk of a damaging one is not negligible. This week, the federal government announced a major upgrade to that network. Lamont will receive $255,000 grant under the American Recovery and Reinvestment Act to beef up cables, power supplies and other hardware, and add monitoring staff for its 34 locations from Vermont down to Maryland. U.S. Representative Eliot Engel announced the grant, saying: “Because of the density of the population and the presence of such facilities as the Indian Point Nuclear Power Facility, it is essential that we monitor for [earthquakes].” Lamont is part of a national network, run in cooperation with the U.S. Geological Survey.