Preliminary Earthquake Report:
An earthquake occurred at 9:06 AM CDT (14:06:30 UTC). This earthquake was located 5 miles ENE of Noble, OK and 8 miles SE of Norman, OK at latitude 35.164 N and longitude 97.316 W. The best estimate of the earthquakes depth is 13 km (8 miles). Felt reports have ranged from Dallas, TX to Wichita, KS and as far east as Arkansas. No aftershocks have been observed as of 5 PM on Oct. 13, but aftershocks are quite likely and some may be felt by local residents. This earthquake did not occur on a known fault, but there are more faults in the rocks in the subsurface of Oklahoma than we could possibly count.
The USGS reported a moment magnitude (Mw) 4.3 and the Oklahoma Geological Survey reported a magnitude (mbLg) of 5.1. So which one is right? They both are, these are two different estimates of an earthquake’s size. They are two common seismological methods for determining the size, or magnitude, of an earthquake, which cannot be measured directly. They often have discrepancies similar to those that we are seeing for this earthquake. It is entirely possible that the magnitude estimates will change over time as further work is done to measure the size of the earthquake. Whether it is a magnitude 4.3, magnitude 5.1, or something in between, it is still a small to moderate sized earthquake. This also makes this earthquake the second or third largest instrumentally recorded earthquake in Oklahoma. Earthquakes of this size have the potential of occurring almost anywhere in Oklahoma at any time.
This earthquake is not related to the ongoing Jones Earthquake Swarm in Oklahoma County nor the recent felt earthquakes in Arkansas. Instead it is a reminder that even though Oklahoma is not on a plate boundary the interior of the North American continent is capable of producing small to large earthquakes. The probability of a large earthquake causing major damage in Oklahoma is small, but it is a real possibility. If you would like to learn how to prepare your family for a disaster of any kind ready.gov is a good place to start.
