August 22, 2003 Earthquake in South-central Maine

The New England Seismic Network reports that two small earthquakes occurred in the Augusta-Waterville area on Friday, August 22, 2003.

The following parameters have been calculated for the larger earthquake, which happened at 2:32:39 PM Eastern Daylight Time:

Magnitude 2.4 Mn
Location 44 deg 26 min North latitude; 69 deg 40 min West longitude
Depth 16 kilometers
This places the epicenter in the town of Vassalboro, about 10 miles north-northeast of Augusta. Because of the very small size of the earthquake, there is a statistical uncertainty of almost two miles associated with the location calculated from instrumental readings.

Further Information:

A slightly smaller earthquake (Mn = 2.1) occurred at 2:31:26 pm, just over a minute before the main shock. The smaller earthquake was probably centered in the Oakland area, but the calculated error is greater than 15 miles.

The Maine Geological Survey received 19 felt reports through its on-line form, from several towns in the Augusta area. Those reports indicate a Modified Mercalli Intensity of III in the immediate area. Several reports specifically mentioned noticing two events, in agreement with the instrumental record.

Town Intensity
Augusta IV
Augusta (9 reports) III
Windsor III
Farmingdale III
Hallowell (2 reports) III
Chelsea (2 reports) III
Gardiner III
West Gardiner III
Augusta II

Last updated on October 6, 2005