Seismic Activity Recorded 2 Miles North of Hampton
By Chris Outcalt
Hampton Union, Friday, June 22, 2007
[The following article is courtesy of the Hampton Union and Seacoast Online.]
HAMPTON -- The fifth earthquake in the last three weeks was recorded on the Seacoast Wednesday evening.
The seismic activity measured two miles north of Hampton registered a one on the Richter Scale and was reported by Portsmouth residents about seven miles from the quake's center, according to Portsmouth police.
Several North Hampton residents reported not feeling the small quake.
"I felt nothing," Selectman Don Gould said. "I'm a sound sleeper."
North Hampton firefighter Philip Sutton said the department did not receive any calls related to the quake and Janet Facella, who works in the Town Office, heard about it on television, but said there's no buzz in the town office.
John Ebel, director of the Weston Observatory at Boston College, said it's not uncommon to see several minor earthquakes in a small area. Ebel, a professor of geophysics at Boston College, said because of New England's past seismicity he wouldn't be surprised to see more quakes in the area — maybe even a bigger one.
"You look worldwide and the places that have the large earthquakes are the places that frequently have more small ones," he said.
In 1727 an earthquake in Newburyport, Mass., registered 5.5 on the Richter Scale, Ebel said. A quake of about the same magnitude hit Amesbury, Mass., in 1999.
But Ebel said Wednesday night's jolt was so small, he had trouble measuring it. And according to a Hampton police dispatcher who was working when it happened, nobody called in to report anything.
Earlier this month the Weston Observatory recorded activity on three consecutive days, all occurring within four miles of Exeter. The largest was a 1.9, logged on June 2 at 1:55 p.m.
Ebel compared the recent seismic activity on the Seacoast to a small quarry blast or construction explosion. Last November when a chemical plant exploded in Danvers, Mass., Ebel said the observatory measured waves equivalent to a 1.4 on the Richter Scale.
"(The Seacoast quakes) had enough energy that it would be a good amount of dynamite," Ebel said.
Because the quakes have all been so small and relatively far from the Boston observatory, Ebel said it's impossible to tell for sure if they are all related. But he guesses they are. "It would not surprise me if they were all coming form essentially the same spot in the Earth," he said. "But we can't exactly verify that."
Tom Mack, who works in the U.S. Geological Survey's New Hampshire office, said there are fault zones that run parallel to the local coastline and that the activity could be linked to those.