Updated Feb. 11, 2010 at 10:53 a.m.
by Martha Quetsch
Brad Hruza of Elburn said that the 4 a.m. earthquake Wednesday was a rude awakening.
â€œThe house didn’t just shake, it felt like it was swaying in the wind,â€ Hruza told The Elburn Herald. â€œIt lasted about 10 seconds, and I thought I was dreaming until I realized everyone in the house woke up.â€
Hruza said some things were falling off shelves and his computer desk.
â€œIt was scary for a bit there,â€ Hruza said.
Lights in the houses in his neighborhood immediately began going on, as the earthquake woke residents. By 4:10, Hruza was on the U.S. Geographical Survey website, which already had confirmed an earthquake had occurred just before 4 a.m. in northern Illinois.
The USGS first reported that the earthquake had a magnitude of 4.3, but later in the morning stated that the magnitude actually was 3.8.
The USGS estimated that nearly 11 million people felt â€œa light shakingâ€ during the quake.
Maple Park Police Chief Michael Acosta was abruptly awakened in his Sugar Grove home at about 4 a.m. by the earthquake. He said he heard a loud thunder and crumbling sound and first thought that a car had rammed into his house.
â€œIt felt like the whole east-side walls had moved,â€ Acosta said.
Acosta said some Maple Park residents initially thought that a train had derailed in the village. No one reported any property damage or injury from the earthquake.
The epicenter originally was reported in Sycamore, Ill., but later in the morning the USGS reported it to be just south of Pingree Grove, Ill. The epicenter’s depth was about three miles.
Elburn and Countryside Fire Department received several calls from residents about the earthquake, but no reports of damage or injury.
Ben Draper contributed to this article.
The largest Illinois earthquake ever recorded was on Nov. 9, 1968, in southern Illinois, measuring 5.4 on the Richter scale, according to the U.S. Geological Survey. The quake downed chimneys, cracked plaster, broke windows and overturned tombstones.
Earthquakes occur when an abrupt easing of strain occurs on a geologic fault, causing movement on the earth’s surface. The most common measure of the size of an earthquake is its magnitude-a measure of the amount of energy it releases within the earth.
Earthquakes with a magnitude of 3 to 4 occur about once a year in Illinois. Larger earthquakes are more rare in the state, approximately once in four years for a quake with a magnitude of 4 to 5 and once in 20 years for one with a magnitude of 5-6.
Source: U.S. Geological Survey