USGS Reports 36 Earthquakes Along New Madrid Fault Last 30 Days

There's a whole lotta shaking going on along the New Madrid Fault over the past month. The USGS is reporting at least 36 measurable quakes during the past 30 days.

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I frequently check the USGS Earthquake site for recent activity and every now and then I'll do a search for earthquake history to see if there's been an unusual uptick in quakes. While there was no major quake during September, the activity level along the New Madrid Fault was high. This map shows the threat areas and 36 quakes registered by the USGS over the past 30 days.

There's nothing really concerning here. The largest quakes during September were 2.8 shakers on the Arkansas side of the New Madrid Fault. As we shared a few weeks ago, there was a small swarm of quakes earlier in September that were felt.

What is the probability that the New Madrid Fault will unleash a major quake? The Missouri Department of Natural Resources provides some exact numbers. Here's what they estimate:

Some scientists believe the probability of a large earthquake (magnitude 7.0-8.0) is about 10% in 50 years.

Scientists remind us that forecasting earthquakes is a very difficult thing to do. But, there is some history we can base expectations on including "current modeling of the NMSZ implies a recurrence interval somewhere between 500 to 1,200 years for a major (magnitude 7.0-8.0) earthquakes. The last strong earthquake (magnitude 6.7) in the NMSZ occurred near Charleston, Missouri on Oct. 31, 1895. " By that measure, we may never see a New Madrid quake above 7.0 in our lifetime. Let's hope.

However, even a 10% chance means we need to always be prepared in case the big one ruins our day sometime in the future.