Rumblings Warn New England of Quake Dangers : Experts say the region is vulnerable to temblors. But making the public heed their message is a ‘tough sell.’

Edward Cotter was just getting out of the shower early in the morning on July 22 when he was startled by what sounded like a distant explosion.

“It was a low rumbling, like deep thunder,” Cotter, 38, a supervisor at a local factory, recalled. “I felt the vibration. It was like a heavy bass stereo.”

When he heard sirens moments later, Cotter assumed that the morning calm had been shattered by a gas explosion. Only later, listening to his car radio, did he discover its true cause: an earthquake.

For Cotter and other residents of southeastern Massachusetts, experiencing a quake was unfamiliar. Police in this small suburban town where the quake was centered, and in surrounding communities, reported hundreds of calls from nervous residents.

While the Abington quake had a magnitude of just 2.9, seismologists said it served as another reminder that--contrary to what many here believe--New England is vulnerable to earthquakes, possibly even damaging temblors.

“The fact that we live in an earthquake-prone area is not something we have to panic about, but it is something we should learn about and learn to cope with,” said John E. Ebel, director of Boston College’s Weston Observatory and associate professor of geology and geophysics at the college.

It’s a message he and other experts are increasingly trying to communicate to the New England public these days, hoping it will lead to steps that will lessen the impact of possible future quakes.

The task is not easy in a region that has long regarded earthquakes as an unpleasant phenomenon peculiar to California, Mexico and other distant spots.

David D. Brown, Maine’s director of emergency management, said residents of his state “equate the possibility of an earthquake with that of a meteor striking their house.”

“Earthquakes are a tough sell,” said Edward B. von Turkovich, a specialist with Vermont’s Division of Emergency Management.

But officials point out that about 20 quakes a year occur in New England. While no major temblors have struck recently, historical evidence shows they have occurred.

In 1727, a magnitude 5 to 5.5 earthquake centered in what is now Newburyport, Mass., shook the East Coast. In 1755, a magnitude 6 quake centered off nearby Gloucester, Mass., caused extensive damage. In this century, a magnitude 5.9 quake struck Eastport, Me., in 1904; twin 5.5 quakes hit Ossipee, N.H., in 1940 and a magnitude 4.2 quake shook Middlebury, Vt., in 1962.

Predicting quakes can be especially tricky in New England, where their cause is not well understood, specialists say. Much of the earthquake activity in California centers around major faults along tectonic plates. But New England lies in the middle of a plate, and while it has numerous faults, seismologists have yet to be able to correlate earthquake activity with them.

Still, based on history, seismologists have estimated that there is a 50% chance of a magnitude 5 earthquake striking New England during a 50-year period, and that quakes with a magnitude as high as 6.5 can occur.

Specialists say several factors make this region especially vulnerable to serious damage. One is that the cold rock of the Northeast enables seismic waves to be easily transmitted and to affect a broad region.

New England also has a population about 10% denser than California’s. And its housing stock--particularly old, unreinforced masonry buildings built on filled land--is not likely to stand up well in a major quake.

Several states, notably Massachusetts, have incorporated seismic provisions in their housing codes, but specialists say the region still lags well behind California in mandating earthquake-resistant building designs.

Quake preparation efforts are proceeding on several fronts. With the aid of funds from the Federal Emergency Management Agency, most New England states have hired specialists to work with schools and public safety departments. The six states have also formed a New England States Earthquake Consortium to coordinate quake mitigation strategies.