Thursday, 4:30 PM
Danvers explosion registers on Richter scale
By Sarah Kneezle and Andrew Ryan, Globe Correspondents
The explosion this morning at a chemical plant in Danvers shot a tower of fire hundreds of feet in the air, rattled windows 20 miles away in Boston and could be felt as far away as New Hampshire.
The blast released such a massive amount of energy, in fact, it registered a 0.5 on the Richter scale at the Boston College observatory, almost 30 miles away in Weston.
While that is only the equivalent of a very small earthquake, scientists said it was still an extraordinary feat for an explosion in which most of the force was released upwards, into the air.
"It was such a huge explosion, I'm not surprised at all that the seismic energy went into the ground and we were able to detect it," said John Ebel, a professor of geophysics at Boston College. He explained that, "most of the energy went up into the air resulting in objects being thrown up in the air and blowing out windows. The airwave does the most damage."
That airwave damaged more than 60 buildings in a 1/4 mile radius around the blast site.
The Richter scale measures the amount of energy released by quakes that are typically deep within the earth.
This morning's seismic readings did not extend beyond the Weston observatory, Ebel said. The next nearest observatory in Smithfield, R.I., did not record a reading from the blast.
