By JACKIE HAUSLER
Published February 8, 2023
Did you feel the earthquake?
That was the hot topic of conversation on Monday, as many of us awoke to a natural phenomenon that is common in California, but not here on the shores of Lake Erie.
UBNow caught up with Tracy Gregg, professor and director of undergraduate studies in the Department of Geology, College of Arts and Sciences, to get her insights on earthquakes in general and on Monday’s event that had its epicenter in West Seneca — a little more than 16 miles from the UB North Campus.
Rocks underground — typically on fault lines— break and energy is then released. How much the earthquake will be felt depends on how big of an area, how many rocks break and how far the rocks move. Larger earthquakes happen when many rocks under the surface are moving at once. After the rocks move, the surrounding rocks need to also move and adjust into place, which is why aftershocks of the earthquake can be felt even days after the initial earthquake. Volcanos can also cause earthquakes to occur.
It is very rare for an earthquake to happen in Western New York, although the earth is capable. What we experienced was a 3.8 earthquake that occurred on an old fault that is still readjusting from tens to hundreds of millions of years ago. This area of the earth used to be under two miles of ice that caused the Earth’s surface to be pushed down. Think of it like when you sit on a mattress and it gets compressed. When the ice melted, the weight was released — similar to when you get up from sitting or lying on a mattress and it pops back up. The Earth is still very slowly springing back. While the forces that are pushing on the rocks aren’t as big now as when the faults were first formed, they can absolutely still produce an earthquake. This fault gave us another earthquake in the early 1990s. Because it is an ancient fault line, thankfully it is not incredibly active.
Earthquakes typically occur a couple of miles underneath the Earth’s surface. So, the U.S. utilizes seismometers — instruments that listen to the energy and sound waves released — to measure earthquakes. When enough seismometers “listen” to same event at the same time (three or more is better to converge the data), we can measure how big the earthquake was. The U.S. Geological Survey (USGS) captures all of this information. For this particular earthquake in Western New York, input from 26 seismometers were used to determine the size. You can zoom in on the "interactive map" and see the location of the epicenter.
It is all based on the amount of energy released. A magnitude of 3.8 is big for this area, but small for earthquakes in terms of the ones that we truly need to worry about. An earthquake has to be about a 2.5 for people to even feel it. Every number up — like from a two to three magnitude — is actually 100 times more than the previous number. Significant damage usually occurs if an earthquake is over 4-4.5 — windows breaking, bricks falling, etc. I should also note that the earthquake in Turkey had no correlation with the earthquake here. It was a coincidence they occurred at similar times.
The earthquake that occurred in Turkey that is a 7.8 on the scale was actually about 10,000 times stronger than the one we had, as measured by earthquake wave amplitude — how much the ground shook. The Turkey quake released almost a million times (1,000,000) more energy than our quake released. It’s not really even comparable to what we felt here.
Earthquake energy and the Richter scale measure slightly different earthquake phenomena, but they are related. Check out the USGS’s interactive calculator.
A lot of effort goes into trying to predict earthquakes, since they are among the Earth’s deadliest disasters. Predicting them could help a lot of people who live on or near fault lines. Geologists all over the world are working hard on figuring it out but there are still many unknowns. Atmosphere or weather do not impact whether an earthquake is going to happen or not.
Thanks to UB emeritus professor Robert Jacobi dedicating his career to mapping the faults in New York, we now know all about fault lines in the state that previously no one even knew existed. In this part of the world, the fault lines run northeast and southwest. If you’re interested in learning more about the fault lines in Western New York, you can read Jacobi’s research 2002 paper, “Basement faults and seismicity in the Appalachian Basin of New York State.”
UB students can take a natural hazards course offered by the Department of Geology in the fall and spring semesters. Most recently, I taught the class in the fall.