The Maine Geological Survey has confirmed that a small earthquake with a magnitude OF 2.3 shook the town of Greenwood late Thursday night. MGS physical geologist Henry Berry said the quake occurred at 10:29 p.m. when rock 3 1/4 miles below the earth's surface broke under pressure.
"Something that deep under pressure if it gives way it sends out energy and generates vibrations....what creates every earthquake is the breaking of rock under stress," Berry said.
Berry said the highest magnitude earthquake recorded in Maine was in 1904 in Eastport, which is estimated to have been a 5.9 on the Richter Scale. He says the chance of Maine having a high magnitude earthquake in the next 50 years is less than 2%.