BOSTON – Buildings in Boston fell, chimneys toppled and cracks opened in the ground, spewing sand and water. Shaking was felt from Nova Scotia to Maryland, and sailors on ships 200 miles offshore felt a tremor so severe they thought they’d run aground.

Scientists who gathered at the Weston Observatory on Monday discussed the 6.0 magnitude 1755 quake, centered off Boston’s North Shore, and reminded Northeastern residents that a similar quake could happen again.

The scientists released a U.S. Geological Survey map three years in the making that shows the location and magnitude of more than 1,000 quakes that have hit 14 Northeastern states between 1638 and 1998.

The map aims to raise earthquake awareness among residents of the Northeast, who typically worry about quakes about as often as they worry about sunstroke in January.

But USGS geologist Russell Wheeler, one of the map’s authors, said the region’s history proves earthquakes are a real threat. If the 1755 quake was repeated today, damage would run to billions of dollars, he said.

“You have to think it’s possible, because the consequences, if it happened, are so severe,” Wheeler said.

The map uses color-coding to show the magnitude of the quakes, and is designed to offer history at a glance, absent scientific jargon that can cause eyes to glaze over.

“It’s a more permanent record, and it’s all in one place,” said John Ebel, director of the Weston Observatory, which is associated with Boston College.

The maps are available free on the Internet, and will be distributed at science and emergency centers around the region.

The earliest quake depicted is a 6.5 magnitude tremor in central New Hampshire in 1638 that sent aftershocks around the region for 20 days. Most recently, a 5.2 magnitude earthquake in 1998 in northwestern Pennsylvania sent people scampering outdoors and sucked the water out of residential wells.

Wheeler said the map also shows that although damaging earthquakes happen, they don’t happen often. The Northeast region is relatively stable because it lies in the middle of a tectonic plate that extends from the San Andreas fault to the middle of the Atlantic Ocean, he said.

Ebel said that regardless of the fairly low risk, preparation is a necessary part of public safety.

“I don’t expect to have a fire in my house soon, but I do have smoke detectors,” he said.

Ebel said more awareness of the earthquake threat can lead to changes such as more regular earthquake drills in schools and stricter building codes that gradually make regional structures more earthquake-proof.

But penetrating a historic indifference about the earthquake threat will take more than a map, Wheeler said.

“It will take time, and we have time … probably,” he said.

On the Net:

http:///greenwood.cr.usgs.gov/pub/fact-sheets/fs-006-01

http:///greenwood.cr.usgs.gov/pub/i-maps/i-2737