Earthquakes In Illinois, Seismic Anomalies Continue

In News today from northern Illinois a small 4.3 magnitude earthquake interrupted the sleep of many people in the area. According to the USGS the quake was centered on the town of Virgil about 50 miles northwest of Chicago. The Kane County Sheriff’s Office was flooded with calls from concerned citizens this morning, though no major damage was reported.

Some residents and business reported various effects from being shaken out of bed to alarms being set off by the seismic disturbance. According to the USGS information, the quake was centered relatively shallowly at around 3 miles beneath the surface.
Quakes in this area of the country are not that common, at least of any significant magnitude. About every 10 years, plus or minus, people in Illinois feel such tremors. The image below shows the most common areas of activity in the Mississippi and Ohio Rivers region. The “shake map” above from the USGS reveals areas where the quake may have been felt.

Illinois earthquake activity

As you can see, this area of instability is quite broad.

Though this Illinois quake is not cause for alarm, it is interesting to note that this is the first disturbance in this area despite many daily seismic occurrences around the continental United States. Of course most activity is linked to the western faults and occurs in California and surrounding states. but significant numbers of tremors still reverberate out ward from the Haiti event. People have asked us repeatedly if the numbers and intensity of earthquakes has increased since that event, but we can only guess that to an extent they have. The image below shows earthquakes in real time for the United States excluding Alaska. As you can see, the one in Illinois (center of map) is desinated by a blue square – indicating the magnitude (by the size of the square) and that it ocurred in the last 24 hrs. (blue).

USGS map of recent North American earthquakes

Blue squares - 24 hours, yellow - week, red - last hour

The reader should know that hundreds of earthquakes of various magnitudes occur around the globe daily. The USGS monitors all this seismic activity along with any number of other geological and geophysical data. Awareness of earthquakes in the United States has obviously been heightened by the recent disaster in Haiti. The Illinois quake is reason for awareness and nothing more at this point. We will keep you appraised if anything develops as we monitor the USGS daily.

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