Preparing for the unexpected — earthquakes

With part of Northern Arkansas in the New Madrid Seismic Zone, the possibility of feeling the effects of an earthquake in the Natural State are very real. The New Madrid Seismic Zone, also known as the New Madrid Fault Line, has been responsible for intraplate earthquakes in the past and has the potential to produce large earthquakes in the future. Earthquakes that occur in the New Madrid Seismic Zone potentially threaten parts of Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, Oklahoma, and Mississippi. Earthquakes occur suddenly and with no warning, so knowing what an earthquake is and how to respond during one proves helpful when the unexpected happens.

An earthquake is the sudden, rapid shaking of the earth, caused by the breaking and shifting of subterranean rock as it releases strain that has accumulated over a long time. Initial mild shaking may strengthen and become extremely violent within seconds. Additional earthquakes, called aftershocks, may follow the initial earthquake. Most are smaller than the initial earthquake, but larger magnitude aftershocks also occur. Earthquakes may cause household items to become dangerous projectiles; cause buildings to move off foundations or collapse, damage utilities, roads and structures and explosions. They may also trigger landslides, avalanches, and tsunamis.

Earthquakes can happen at any time of the year and occur without warning, although they usually last less than one minute. Aftershocks following the initial earthquake may occur for hours, days, or even months.

Fracking

Hydraulic fracturing, also known as fracking, is a method of oil and natural gas extraction that involves injecting high pressure. As of May 2017, hydraulic fracturing in Arkansas occurred primarily in the Fayetteville Shale, a geological formation that spans northern Arkansas. As of May 2017, there were 46,973 oil and gas wells in Arkansas, according to the Arkansas Oil and Gas Commission. Of that total, 6,335 wells — 13.5 percent — were hydraulically fractured. The term “induced seismicity” refers to seismic events that occur at higher than normal rates due to human activity. Induced seismic events (such as small earthquakes and tremors) can be the result of mining, damming wells during fracking.

In 2014, however, the U.S. Geological Survey concluded that the actual hydraulic fracturing process is only very rarely the direct cause of felt earthquakes. While hydraulic fracturing works by making thousands of extremely small “microearthquakes,” they are, with just a few exceptions, too small to be felt; none have been large enough to cause structural damage. Underground disposal of wastewater co-produced with oil and gas, enabled by hydraulic fracturing operations, has been linked to induced earthquakes.

What to do during an earthquake

During an earthquake — if you are inside a building — drop down onto your hands and knees so the earthquake doesn’t knock you down. Cover your head and neck with your arms to protect yourself from falling debris. If you are in danger from falling objects, and you can move safely, crawl for additional cover under a sturdy desk or table. If no sturdy shelter is nearby, crawl away from windows, next to an interior wall. Stay away from glass, windows, outside doors and walls, and anything that could fall, such as light until the shaking stops and do not run outside or seek shelter in a doorway. A doorway does not provide protection from able to remain standing.

If you are in bed, stay there and cover your head and neck with a pillow. At night, avoid. Attempts to move in the dark result in more injuries than remaining in bed. If you are outdoors when the shaking starts, move away from buildings, streetlights, and utility wires. Once in the open, cover your head and neck with your arms, and if a safer place is nearby that you can get to crawl to it and hold on to maintain cover. This is known as “Drop, Cover, and Hold On.”

The last earthquake caused by the New Madrid fault occurred on Feb. 7, 1812, and was the third in a series of three earthquakes beginning on Dec. 16, 1811, in Northeast Arkansas. It has been more than 200 years since the last major earthquake on the New Madrid fault — but since earthquakes are impossible to predict, those living in the Natural State should be prepared for the unexpected.