Earthquakes can happen anywhere
Southwestern Pennsylvania has certainly been enjoying some nice warm weather for the past several weeks. September started out on the cool side with temperatures well below normal, but come mid-month, that quickly changed. The first two weeks saw temperatures average seven degrees below normal and the last two weeks, we have been averaging eight degrees above normal. By the time you read this article, the warm days will be over with the 80s giving way to the 60s, although we do see another period of nice warm weather in early October.
On September 25, 1998, we experienced a different event as an earthquake occurred at 3:53 p.m. that day and was centered 20 miles west of Sharon. Magnitude was 5.2 on the Richter Scale, which is used to measure the severity of earthquakes. This was the strongest earthquake ever measured in our state and although damage was light these events can occur in this region as well. Tremors were felt as far north as southern Ontario and as far west as Detroit. The quake was also felt in the city of Pittsburgh.
The quake came to be known as the Pymatuning Quake and has been studied extensively by hydro geologists. In a recent book by Kathryn Miles titled 鈥淨uakeland,鈥� she discusses the 120 households that lost all the water in their wells as a result of the quake. New springs and small lakes began appearing.
Other wells overflowed and flooded backyards and basements. Mini geysers erupted in vegetable and flower gardens. River gauges on the Little Shenango River rose. In time, some of the wells came back while others stayed dry. This was one of the most studied earthquakes in the East.
Another earthquake that was felt in Pennsylvania occurred in 2011. This event caused major damage in the Washington D.C. area, including the Washington monument, the National Cathedral and Union Station. Because of the slender nature of the Washington monument, it sustained extensive damage, taking 3 years and $15 million to repair.
We usually think of the western states when it come to earthquakes, however they can occur in a lot of places that we don鈥檛 think are vulnerable. Damage from earthquakes has occurred in all 50 states. The largest earthquake in the contiguous United States occurred in 1812 along the New Madrid fault which winds through Missouri, Illinois, Tennessee and Arkansas. It measured 8.0 on the Richter Scale.
Today, more than 12 million people live in this area. It is called St. Louis.
In 1812, it was just rural farmland. In 1964, a quake in Alaska measured 9.2. The Richter scale goes from 1 up to 10. Each whole number on the scale represents a 10 fold increase in severity.