Small earthquake shakes Sussex County

Hamburg — The phenomenon so common in California made a brief yet noticeable impact last Thursday night when an earthquake startled residents in eastern Sussex County, most noticeably in Hamburg and Hardyston. Residents reported another earthquake on Monday evening, which experts have classified as an aftershock. It was the sixth in a series of aftershocks, but the only one felt by residents. The original quake lasted about seven seconds and registered a 2.6 reading on the Richter Scale, which is considered minor, experts said. However, the event might be considered disconcerting to those who are not used to it. The aftershock on Monday was a 1.3; all the other aftershocks occurred Thursday night or early Friday morning and came in under 1 on the Richter Scale. “It was felt from Lafayette clear up into Warwick, N.Y., and there were indications it was also felt in the Blairstown area,” said Eskil Danielson, Sussex County’s emergency management director, the morning after the quake hit. Danielson said that at first emergency management coordinators from some of the towns involved went looking to see if an explosion of some sort had occurred, but at the same time, they theorized that it may have been an earthquake. “We were able to come up with the fact that it was an earthquake,” Danielson said. “It was characterized as a minor earthquake.” The Ramapo Fault, a lengthy fracture that cuts through northern New Jersey and separates the Piedmont and Highlands Physiographic Provinces, was blamed for the quake, which occurred at 6:43 p.m. Daniel R. Dombroski Jr., the principal geologist of the state’s Bureau of Geology and Topography, wrote in an online report, “New Jersey doesn’t get many earthquakes, but it does get some. Fortunately, most are small.” Danielson said the quake originated about five miles below the earth’s surface, with an epicenter that seemed to be in or near the Hamburg area. Conversations with people affected indicate that the quake was felt more in the western portion of town, closer to the Hardyston border. Yet others seemed unaware of the tremble until hearing it broadcast on the news that night or the following morning. “I wasn’t home,” said Hamburg resident Jennifer Brennan, who lives closer to the Franklin border, on the east side of Hamburg. “My daughter called and said, ‘Mom, we’ve had an earthquake.’ They felt it. My husband felt it. The kids felt it. They said it was very minor. But in another place, someone said it was like a bomb went off.” For Lindy Brown, who owns the Body Boutique hair salon at the intersection of routes 23 and 94, the event was more noticeable. “I was at work when it happened,” Brown explained. “I sent the girls outside to see if a truck had hit the building. The lights shook, and the windows were shaking.” Jessica Sigala, a seismologist with the National Earthquake Information Center, based in Golden, Colo., said that the tremor “was actually a pretty small earthquake, and it was felt pretty widely. The Hamburg area was the one with the most reports that we received.” Sigala also confirmed that the quake was felt more significantly on the western side of Hamburg. Experts explained that for every point recorded on the Richter Scale, there is an additional “10-fold increase” of energy released. In other words, an earthquake that recorded a 3.6 on the Richter Scale would be 10 times as powerful as the one in Hamburg. By this logic, the earthquake that hit San Francisco in April 1906, which is now thought to have been either a 7.7 or 7.9 registering on the Richter Scale, had more than 100,000 times the power of the quake in Hamburg. Dr. Won-Young Kim of the LaMont Doherty Earth Observatory in Palisades, N.Y., explained that since 1970, there have been 100 earthquakes in New Jersey, some with a magnitude of less than 1 on the Richter Scale. All of them, he said, were considered minor by universal standards. That’s not the whole story, however. “A 2.6 is big in New Jersey, but if you go to California, it’s nothing,” he said. “Of course, an earthquake of 2.6 in that area can occur anytime. But the likelihood is very low, according to what has happened in the past.” Kim also said that two bigger quakes did occur in New Jersey but a long time ago: one in 1737 in Bergen County with a magnitude of 5.2 and another in 1783, again in Bergen County, with a 4.9 magnitude. Neither one was directly related to the Ramapo Fault.