Did you feel it?

Texas isn’t exactly known for its earthquakes.  That’s not to say they don’t happen here.  On the contrary, one or more earthquakes are measured somewhere in the state nearly every day.  Most are negligible, however, and many occur without being felt.

Yet the past 36 hours have been rather surprising when it comes to earthquakes.  That’s because we’ve had eight occur within the DFW metroplex.  (The USGS has the scoop.)

Don’t get too excited, though.  The strongest was a 3.0.  It set off a few car alarms and shook the ground a bit, but its effects were no more noticeable than a heavy truck rumbling through the neighborhood.  There will be no national coverage of collapsed highways or buildings turned to rubble.

As for the other seven temblors, they ranged from 2.5 to 2.9 on the Richter scale.  More than 16 recorded geological events (earthquakes plus aftershocks) have been measured in DFW since 11:30 PM CDT Thursday night when this all began.

All of the epicenters have been in the same general vicinity (western Dallas county).  That obviously begs the question of why so much activity has occurred in such a short time where no earthquake has been measured before.  Prior to this volley, the closest earthquake was recorded in March 1950, a 3.3 in Valley View about 70 km northwest of Fort Worth (one in 1985 and another in 1997 were even further away).

In truth, the best explanation comes from the USGS with regards to earthquakes east of the Rocky Mountains:

At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case. All parts of this vast region are far from the nearest plate boundaries, which, for the U.S., are to the east in the center of the Atlantic Ocean, to the south in the Caribbean Sea, and to the west in California and offshore from Washington and Oregon. The region is laced with known faults but numerous smaller or deeply buried faults remain undetected. Even most of the known faults are poorly located at earthquake depths. Accordingly, few earthquakes east of the Rockies can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. In most areas east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves.

All in all, this apparent swarm of earthquakes probably means little.  An unknown fault—or even a known one—likely is catching its breath after a very long period of dormancy.  Despite the lack of any real threat, this has offered up an unusual kind of excitement in an area where earthquakes are always spoken of in terms of happening someplace else.  To experience eight of them in less than two days, all of them centered right in the heart of the metroplex, gives us something new to talk about besides the terribly boring weather we’ve been having.

5 thoughts on “Did you feel it?”

  1. I think there is an issue with the barnett shale that chesapeake is drilling in. I think they are taking out so much gas, the pockets where the gas were are collapsing. I think Chesapeake is going to have lawsuits on there hands very soon

  2. That’s one of many possibilities. The removal of water, oil and gas from underground reservoirs can lead to significant changes to geological structures. It certainly could explain this sudden activity. And the Barnette Shale runs from Dallas to west of Fort Worth and points south.

    The USGS has already stated they can’t pin this on any one fault in the North Texas area–at least not yet. There are some here, most notably the conjunction of the Ouachita Techtonic Front and the Balcones Fault Zone, both of which converge in western Dallas county (along with the Fort Worth Basin, the East Texas Basin, and an untold number of other geological structures).

    The proof will be in the pudding, as they say, when the whole of the situation is better understood. For now we have the possibility of facing these tremors for up to three weeks–and that’s assuming the cause is understood to even the smallest degree.

    No matter what the underlying issue might be, I find it all rather exciting and intriguing, something worth more than the casual mention we now give tornadoes and the like.

  3. let chesapeake keep taking out the resources and watch the scale of these quakes increase both in strength as well as numbers

  4. I notice it finally ended with 10 earthquakes in 48 hours (not to mention a sizable number of aftershocks too small to pin down to that location). Interesting…

    An article yesterday showed how a deadly and catastrophic mud volcano in Indonesia was the result of drilling. That volcano has been erupting since May 2006 and has displaced many thousands of people, destroyed many homes and business, and killed scores of people. Truth be told, it’s quite possible drilling in the Barnette Shale could be the cause of these earthquakes; more troubling is that the same drilling could produce even bigger problems than these minor temblors.

  5. Now, take that theory into the ocean where drilling is going on and will likely increase over the next 10-20 years…if you start to have earthquakes out there, what else will generally happen? Tsunami…now, I know that is reaching way out but the possibility is still there.

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