This week, a small earthquake surprised people near Richmond, Virginia, highlighting the fact that the East Coast can also experience seismic activity.

The 2.8 magnitude quake struck approximately 6 miles northwest of Glen Allen and about 13 miles from Richmond’s city center on Tuesday around 5:30 p.m. EST, as reported by the U.S. Geological Survey. Residents in the Richmond area and Henrico County felt the tremors, according to local news station WTVR. Fortunately, no injuries or damage were reported.

In 2011, a significant earthquake occurred near Mineral, Virginia, roughly 50 miles from Richmond, which became the most widely felt quake in U.S. history, according to the USGS. The earthquake on August 23 caused damages exceeding $200 million, affecting landmarks like the Washington Monument and the National Cathedral in Washington, D.C.

Although it registered a magnitude of 5.8, making it less powerful compared to some earthquakes nationwide, its impact was felt over a much larger area due to the unique geological conditions of the East Coast, unlike the more frequent quakes experienced on the West Coast.

Are earthquakes on the East Coast uncommon?

In general, earthquakes happen much less often in the eastern U.S. compared to the western part of the country. However, they have been recorded in every state east of the Mississippi River, with most states experiencing damaging quakes at some point in history.

Globally, seismologists track around 900,000 earthquakes each year, but the vast majority occur along tectonic plate boundaries, which are not found in the eastern or midwestern United States, according to Michigan Technological University’s Department of Geological and Mining Engineering and Sciences.

Occasionally, smaller to moderate earthquakes catch residents off guard in states like New York and New Jersey.

There are records of strong earthquakes in the East, with historical data enabling estimations of their magnitudes. For instance, in November 1775, a 6.0 magnitude earthquake, located 50 miles outside of Boston, caused considerable damage in the city. An earthquake that struck Charleston, South Carolina, in 1886, registered between 6.8 and 7.2 and resulted in significant destruction in the area.

The Virginia earthquake of 2011 also triggered landslides as far as 150 miles away and produced damaging tremors over an area much larger than previously noted, according to a USGS report published the following year.

Why are East Coast earthquakes experienced differently?

While East Coast earthquakes typically have lower magnitudes compared to those in states like California, they can be more alarming because they tend to impact a broader region, according to the USGS.

This difference arises because the rocks in the eastern U.S. are often much older, in some cases by millions of years. These older formations have endured extreme temperatures and pressures over time, allowing faults to become denser and less easy to absorb seismic energy, enabling vibration waves to travel further. Conversely, the newer faults in the West absorb more seismic energy, limiting their reach.

The 2011 Virginia quake was felt by millions, resulting in around 4,000 aftershocks, some continuing even a decade later, according to the USGS.

Additionally, earthquakes on the East Coast produce “higher-frequency shaking (rapid back-and-forth movement) compared to similar events on the West Coast,” the USGS indicated.

“While damaging earthquakes do not often occur in the eastern United States, the potential consequences of underestimating and failing to prepare for such events with their widespread impact could be significant,” stated USGS Director David Applegate in 2021. “Although the next major earthquake on an eastern U.S. fault might not happen for hundreds of years, it could still occur at any moment.”

Contributing: Gabe Hauari.