BELFAST —The epicenter of a small earthquake was just two miles northwest of Belfast at 11:25 p.m. on Nov. 23, but it was strong enough, at magnitude 2.0, to be felt in Camden, Morrill and Union, among other towns, with reports of a loud bang.

The depth of the earthquake was at approximately 4 kilometers (2.48 miles).

In Belfast, the intensity was recorded at III on the Modified Mercalli Intensity scale, which depicts shaking severity, according to the Association of Bay Area Governments in Oakland, California.

Read about the Belfast quake at the U.S. Geological Survey

And at the event page

A history of earthquakes in Maine

"An earthquake has a single magnitude that indicates the overall size and energy released by the earthquake," the association says at its website. "However, the amount of shaking experienced at different locations varies based on not only that overall magnitude, how far you are from the fault that ruptured in the earthquake, and whether you are on rock or thick valley deposits that shake longer and harder than rock."

Larger earthquakes taking place on Nov. 23 at various spots on the globe were record in Burma, Puerto Rico, Indonesia and California. Earthquakes are a regular occurence throughout the world, and the Geologic Survey keeps a constant tabs on where they have been recorded with this map.

However, in order to make the map, earthquakes have to reach a magnitude of 2.5; Belfast's was 2.0. There have been 216 earthquakes in the world over the past seven days with magnitude 2.5 and more. The biggest was 5.9 in Chile on Nov. 21.

 Citizens filed reports of sensing the Belfast earthquake at U.S. Geological Survey's Earthquakes Hazard Program.

"New England is laced with known faults but numerous smaller or deeply buried faults remain undetected," according to the USG. "Even the known faults are poorly located at the depths of most earthquakes. Accordingly, few, if any, earthquakes in New England can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. As in most other areas east of the Rockies, the best guide to earthquake hazards in New England and Long Island is the earthquakes themselves."

The largest earthquake ever reported in Maine occured on March 21, 1904, when, according to the Maine Department of Conservation, "a shock overthrew some chimneys at Calais and Eastport, Maine, and St. Stephen, New Brunswick. The total felt area covered most of New England and the Canadian Provinces of New Brunswick and Nova Scotia, approximately 150,000 square miles. There were several light shocks near the origin a few hours after the main earthquake."

In Maine, earthquakes are not uncommon, according to the Maine Department of Conservation's Bureau of Geology, Natural Areas and Coastal Resources, which compiled the following list.

Maine Earthquakes 1997 to Present

Asterisk (*) indicates earthquakes felt in Maine, but with epicenters outside Maine.
Most microquakes (magnitude less than 2.0), which are generally too small to feel, are not listed here.
(C) indicates a Coda magnitude; all others are Nuttli magnitudes.
Dates are given in local Maine time (EST or EDT).

Information Sources: Weston Observatory of Boston College, U. S. Geological Survey, Earthquakes Canada G.S.C., Maine Geological Survey

http://earthquake.usgs.gov/earthquakes/dyfi/events/us/c000dxll/us/index....