Folks who live in and around Flomaton down in Escambia County along the Florida line have noticed some unusual seismic activity in the last couple of weeks. Yes, there have been earthquakes felt in southwest Alabama ... three of them since March 6th!
Earthquakes are a global phenomena. Dozens of them occur around the world every day. But it's unusual to have one in Alabama, not to mention three in our state in a 14 day span.
Fortunately, the quakes were weak and caused no problems.
To understand earthquakes, you need to understand that they are measured on the Richter Scale named for its creator, physicist and seismologist Charles Richter (although many scientists have switched to the newer Moment Magnitude scale). The most recent trio of shakers in Alabama and Florida were recorded as a 2.6 tremor in Florida near the Alabama line on Wednesday March 6th, preceded by a 3.1 magnitude quake on Monday, March 11th, (the largest of the three), and a 2.1 quake on March 13th.
It's helpful to understand that the Richter Scale is a logarithmic scale. That means the vibrations measured from a category 4 earthquake are 10 times stronger than for a quake with a rating of 3. A magnitude 5 is ten times stronger than a 4, and so on.
The strongest earthquake ever recorded in our state happened about 4 p.m. on Wednesday, October 18, 1916. It registered a 5.1 on the Richter Scale — the only 5-plus quake ever recorded in Alabama. It originated east of Birmingham and was centered near Easonville in St. Clair County. In downtown Birmingham, buildings were reported to have swayed as the quake rolled through.
The most significant problem was reported near Birmingham in Irondale, where the city's underground water supply was seriously impacted. Authorities reported five water wells in a one-block area in the town went dry immediately after the quake hit and the water levels in many others were lowered.
Freestanding masonry chimneys seem to be the favorite target of earthquakes. In Irondale, authorities reported 14 chimneys in a two-block area were heavily damaged, six others were knocked down to roof-top level and many others were damaged so seriously that they had to be torn down. Residents who lived in the seven-state area surrounding Alabama felt the effects of the earthquake. Scientists say aftershocks were reported off and on for about 10 days after the initial shock was recorded.
Another earthquake shook Northeastern Alabama at 3:59 a.m. CDT on Tuesday, April 29, 2003. The US Geological Survey measured it as a magnitude of 4.6 while others reported it as high as a 4.9. The quake could be felt in 11 states up and down the East Coast and as far north as southern Indiana.
This quake reportedly caused moderate damage in North Alabama including a 29-foot wide sinkhole northwest of Fort Payne.
If you want to learn more about really powerful earthquakes, you need to look west ... not to just to California as you might think — but northwest to Alaska, which has cornered the market on big quakes in the United States.
The top 8 "most severe" quakes in U.S. history all occurred in the 49th state — including the second strongest in world history. Ironically, that 9.2 magnitude Great Alaska Quake occurred on Good Friday, March 27, 1964 .The shaking lasted about four minutes — enough time to inflict huge damage in southwest Alaska and in its most populous city of Anchorage.
When you mention earthquakes in the U.S., many folks recall the famous 7.9 magnitude quake in San Francisco in 1906. While quite powerful, it was not the most powerful quake ever recorded (tied for No. 17).
You may remember the World Series earthquake on Tuesday. October 17, 1989. The Oakland A's were ready to play the San Francisco Giants in Candlestick Park in Game 3 when the 6.9 magnitude earthquake struck south of Oakland. It was the first time millions of viewers had a chance to experience a quake live on national television.
I remember being in the newsroom WSFA TV that night getting ready to watch ABC's coverage of the game. Al Michaels and Tim McCarver were broadcasting the game — doing their routine recap of games 1 and 2, anxiously awaiting the start of the first World Series game in 27 years at Candlestick Park. About four minutes into the broadcast, ABC lost its signal from the ball park when the quake struck. The network put up a full-screen graphic and a short time later Al Michaels' audio only came back on the air as he gathered his thoughts. Finally he said, "That's the greatest open (the beginning of the broadcast) in the history of television... bar none!"
Thank goodness strong earthquakes are something we have never had to contend with in our part of the world.