Stress is a part of life.
We all face it, even the Earth- but in a different way, and we all release it- in a different way. When the Earth’s surface builds up stress- it releases with a shake. Earthquakes!
To visualize this put your hands together and apply some pressure- now try to slide one past the other. It’s not exactly smooth right? There’s that stress or friction on plates that make up the Earth’s surface. These plates are constantly moving, rubbing against each other- sometimes it’s smooth with not much resistance, other times… not. That stick then slip releases energy in the form of seismic waves- an earthquake. These slips happen all the time, across the globe. But are focused on areas called faults. These are weak points in the earth’s surface.
“You can imagine if you put pressure on something that already has a crack in it- if it’s going to slip, it’s going to slip where you have that weakness,” Anji Shah said. She’s a research geophysicist with the USGS who is working to better understand our own faults here in the Lowcountry. She continues, “the faults in Charleston are very different from the faults in California, say the San Andreas fault, as these are ancient faults that formed millions of years ago.”
These faults, located a half a mile to a mile beneath our feet, have only been estimated indirectly by looking at those smaller earthquake clusters. A new project, lead by her is mapping these faults using surveys from planes- measuring the magnetic fields of the different rocks underneath the surface.
“We want to map them out in order to determine which ones might go off, might rupture in an earthquake and number two: to better assess the risk or the probability that these will rupture- especially in a stronger earthquake.”
Determining the size of the fault will explain a lot- as the length of the fault which ruptures is directly correlated to the intensity of an earthquake.
This project will not be able to predict when earthquakes will happen, but by better understanding the risk that is under the Lowcountry- we can be better prepared. This project is finishing up surveys with the results coming at a later date.
Storm Team 2 Meteorologist David Dickson