The source of the mysterious booms that shook Connecticut during the Thanksgiving Holiday Weekend has been determined. And once again its microquake.
The two microearthquakes (magnitude 2.1), centered about two kilometers below the surface at the intersection of Route 184 and 117, were recorded by the U.S. Geological Survey.
Why do earthquakes make sound?
Seismic energy from earthquakes produces “P Waves,” which move by compressing whatever medium they travel through. When a P Wave hits the earth’s surface it causes the earth’s surface to fluctuate rapidly up and down. Very, very quickly. Basically, the ground mimics the diaphragm of a speaker, amplifying the frequency of the seismic energy, which is low, but high enough for humans to hear as a low-frequency booming noise.
Why does Connecticut get these earthquakes with no tectonic plate boundaries near the state?
Starr said there’s a few theories about this, but one explanation lies in the distinction between inter-and-intra plate earthquakes. Interplate quakes are what they get out in California. Here in New England, we get intraplate, which are quakes that happen within a plate, far removed from any major tectonic fault lines.
In the middle of the plate there are areas of weakness, faults that were formed millions of years ago that today are being reactivated because the North American Plate (under Connecticut) is being compressed by the Mid-Ocean ridge. Thus, stress builds on these old faults which rupture and create an earthquake.
These types of quakes are common to Connecticut and even happen further south. In 2011, a 5.8 magnitude earthquake centered in Virginia damaged the Washington Monument and the National Cathedral.
These microquakes may be the reason for the mysterious Moodus Noises, which have become a big part of Connecticut folklore.