Seismologists have now had time to study the seismic data on that little "micro-quake" that tapped Baltimore County at about 8:28 a.m. on Monday. Turns out the tremor was actually centered beneath Lochearn, off Liberty Road just west of Baltimore, and not the southwestern community of Arbutus, near the UMBC campus, as initially reported.

That's not the only revision. (This sort of reassessment and adjustment is normal after a quake as more data is evaluated. These things take time.)

It turns out Monday's event was also a tad stronger than initially stated - a twitchy 1.5 on the Richter scale, rather than 1.3.  That's not inconsiderable, but also not a lot, at a difference of two-tenths of a Richter number. Each whole-number increase in Richter measurement represents a 32-fold increase in the energy released. At 1.5, it's the energy equivalent of 392 pounds of TNT, not unlike a conventional WWII bomb.

And, the Monday tremor occurred deeper under the surface than initially estimated - 5 miles instead of 3 miles.

Finally, because it was less than a 2-pointer on the Richter scale, it was both common - more than 8,000 a day somewhere on the planet - and "unfelt" as geologists rate such things.

Maybe so, but there have been a few people who have reported sensing something of the quake. We got this email from "Cathy:"  "We heard/felt it at our law office in 'downtown' Arbutus. We thought is was either thunder or a big tractor-trailer."

At the Maryland Geological Survey, Jim Reger also told Sun reporter Dennis O'Brien yesterday he had heard from residents of Edmondson Heights, just outside the city line, between US 40 and I-70. Another person living near Lake Montebello, on the other side of Baltimore City, reported feeling or hearing the jolt.

The tremor was also detected by instruments 180 miles away, maintained by the Lamont-Doherty Cooperative Seismographic Network.

There's one other interesting note. Similar micro-quakes have been recorded recently in other parts of the Northeast. There was one, in Hackensack, N.J., measured at 1.3 on the Richter scale, at 8:48 a.m. last Friday. Another, also at Richter 1.3, was recorded 8 miles north of Lawrence, Mass. at 7:15 a.m. on Monday, just 73 minutes before the Lochearn quake.

Curiously, of you look at all three of these spots on a map (three blue dots on the following linked map), they form an almost perfect straight line. But Reger says there's no single fault line that would explain the coincidence.

Once again, if you heard or felt this little tremor, leave a comment here and describe it. Here's more on Maryland quakes.