A magnitude 3.8 earthquake

Earthquake

An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 hit Northern Illinois

Northern Illinois

Northern Illinois is a region generally covering the northern third of the U.S. state of Illinois.-Economics:Northern Illinois is dominated by the metropolitan areas of Chicago, Rockford, and the Quad Cities, which contain a majority of Illinois' population and economic activity, including...

 at 03:59:35 a.m. CST (09:59:35 a.m. UTC

Coordinated Universal Time

Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

) on February 10, 2010. Originally measured at a magnitude 4.3 and a depth of 3.1 miles (5 km), the earthquake's epicenter

Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...

 was about 43 miles (69.2 km) west-northwest of Chicago

Chicago

Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

, 2 miles (3 km) east-northeast of the village of Virgil

Virgil, Illinois

Virgil is a village in Virgil Township, Kane County, Illinois, United States. It was incorporated as a village on November 6, 1990. The population was 329 at the 2010 census, up from 266 at the 2000 census....

 in Kane County

Kane County, Illinois

Kane County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 515,269, which is an increase of 27.5% from 404,119 in 2000. Its county seat is Geneva, and its largest city is Aurora.- Geography :...

, and 2.5 miles (4 km) northwest of the village of Lily Lake

Lily Lake, Illinois

Lily Lake is a village in Kane County, Illinois, United States. The town is 11 miles southwest of Elgin and 43 miles west of Chicago. The village is part of the Chicago metro area. It was incorporated as a village on November 6, 1990...

, also in Kane County, at a depth of 6.2 miles (10 km). The epicenter of the quake was near the Sandwich Fault Zone

Sandwich Fault Zone

The Sandwich Fault Zone is a fault zone that runs northwest from Oswego to Ogle County, transecting Lee County in Northern Illinois. The fault has generally not been active, although there was a minor earthquake in 2002, and another, slightly larger one, in 2010...

, which is less active and less known than the other fault line in Illinois, the New Madrid Fault. The quake was felt throughout the Midwest

Midwestern United States

The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....

, and as far away as Tennessee

Tennessee

Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...

 and Georgia

Georgia (U.S. state)

Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

. According to a local geologist, earthquakes in the area are uncommon, occurring only about once every ten years, and not much is known about the fault that they originate from due to the scarcity of quakes to study.