Wednesday, March 30, 2016

Standing on Shaky Ground

It was a hot Sunday afternoon in July, a slight breeze stirred and the sun was poking out of the clouds that had hung around most of the day after some brief showers that wandered through earlier.  My sister was inside the mobile home we lived in cooking while my mom was mowing the back yard.  My dad was working on the farm that day and I was on the porch of our home being a typical six year old; hammering nails into a two by four for whatever reason.  I raised the hammer to strike a nail and as contact was made, the whole porch started violently shaking.  I tossed the hammer down and ran out into the yard, fully thinking I had caused the end of times.  I ran to my grandmother's house next door and my great-aunt was crouched on the floor yelling, "oh honey, it's an EARTHQUAKE!"  In a couple of minutes, the shaking was over but our nerves were still rattled.

The strongest recorded earthquake in Kentucky happened Sunday, July 27, 1980 at around 2:50 p.m.  The magnitude 5.2 quake was centered just west of Sharpsburg and  felt as far north as Canada.  There was some slight damage to brick chimneys, foundations and some small cracks in the ground in Bath County, with more damage noted in Maysville some forty miles north.  According to the United States Geological Survey, some thirty aftershocks were recorded, with a 2.5 magnitude aftershock recorded July 31.  When people think of earthquakes, they usually envision large faults like the San Andreas Fault or the New Madrid event; that they won't occur in the area of Kentucky Bath County lies. So, what exactly is a fault?  A fault is basically a crack in the rocky areas deep in the Earth's crust.  These cracks are from the movement of rock mass against other rock masses.  Large faults are the result of what's called plate tectonic forces, where large masses of rock cause boundaries between the plates the rock beds set upon.  Energy released when one of these plates move causes an earthquake. 
Fault line along I-64 in Bath County
There are a few ancient faults that lie far below the surface of Bath County; one is in plain sight along Interstate 64 near the 117 mile marker headed east bound.  The rocks along the cuts in the hillside reveal a shift in the geology where, millions of years ago, the Earth's tectonic plates collided.  This fault is very old and dormant, running across the interstate to Day Road, where it is deep below the surface and out of sight. 

Earthquakes have been recorded in Kentucky since the late 1700's when the early explorers began settling the Bluegrass State.  The most famous earthquake to affect the state was the New Madrid event in 1811 when a series of magnitude 7+ earthquakes rocked the Missouri/Kentucky border.  Starting December 16, 1811 with a powerful estimated 7.5 quake, the event was felt over 976,000 square miles.  Damage to structures within close proximity was limited due to the area being sparsely populated, but the landscape was changed greatly.  Landslides, sand blowouts from fissures occurred, and in some cases, land simply disappeared; sinking below the ground;  Reelfoot Lake in western Kentucky was formed due to the land sinking.  In some places the land thrust upward and islands in the Mississippi River disappeared totally.  Further away from the epicenter, damage was reported all over Kentucky and Cincinnati, as well as throughout Tennessee and St Louis, Missouri.  Two more powerful quakes struck on January 23, and February 7, 1812, both with a magnitude estimated as 7+.  The stories of the Mississippi River running backwards is not entirely untrue; the intense shaking churned the water with such great force, boats were toppled and portions of the riverbanks collapsed.  There were no modern seismographs in the area back then, so the magnitudes of the quakes were just estimations, and may be underestimated.  Undoubtedly, these earthquakes were felt in Bath County, however there is no mention of them in John Richards' book.

USGS map showing the areas affected by the 1980 earthquake
The Kentucky Geological Survey's website shows in addition the the fault that runs across Interstate 64, there is another that runs from the Montgomery County line near Saltwell Road and extends across the countryside to a point just south of US 60 and west of Bob-O-Link Drive.  Curiously, the fault that sparked the 1980 quake isn't shown on the interactive map.  That earthquake was classed as a right lateral strike slip type event focused in a northeast direction.  Maysville reported the most damage to older buildings in town; mainly cracked chimneys and bricks or tiles knocked off.  The total damage from the July 1980 earthquake reached over a million dollars, with  59 homes and 27 businesses sustaining major damage and 210 homes and 10 businesses with minor damage in Maysville alone.  In Owingsville, the damage was minimal, with some older buildings receiving cracks in foundations, chimneys and mortar.  It was said at the time that the balcony at the Majestic Theater was damaged, however I am unable to verify that information.  The ornate brick and concrete roof facades on the older business district received some damage and was enough concern to have them removed later.  Thankfully, no one was reportedly injured, but nerves were on edge after the earthquake.  Most people, like me, were caught off guard and had no inkling that an earthquake could happen in Bath County.  This event seemed like just a random, isolated incident that was a quirk of nature.

The evening of September 7, 1988 was a typical late summer evening.  Around 10:30 p.m.,I was lying in bed when a loud boom sounded and the house began violently shaking.  I immediately jumped out of bed, thinking a car had ran off Wyoming Road and into the house.  We ran outside as the earth started settling down from the rumbling and checked on my sister and her family next door.  While outside, a low roar started northwest of our location and gradually increased as a strong aftershock rolled across the land.  The 4.6 magnitude earthquake centered along a tributary fault near the location of the 1980 event, but this time the energy moved in a southeastern direction, meaning Owingsville and surrounding communities would feel the most shaking.  It was felt in five states and registered on seismographs in Canada.  There were twenty-three aftershocks within the following two weeks, most too small to feel.  There were some reports of the usual damage to brick walls, chimneys, basement walls and mortar cracking, but no injuries or major structural damage reported.  Once again, we were all rattled physically and emotionally thanks to Mother Nature.

A few more smaller earthquakes have shaken Bath County in recent times; in fact, a total of eight recorded earthquakes have happened since 1980's big one.  Most have been small, ranging around 2.3 to 2.5 on the Richter Scale and rarely felt.  The largest Bath County earthquake since 1988 was a 3.3 magnitude centered near Blevins Valley Road, close to Old State Road, on September 8, 1990.  Another 4.2 earthquake near Hazard, Kentucky was felt as just a slight rumbling in Owingsville on November 10, 2012. The most recent quake in Bath County was December 23, 2013 and registered 2.3 magnitude very near the center location of the 1988 event.  That quake made a loud booming noise and the shaking was felt in Mount Sterling, causing a flood of calls into the 911 center at Montgomery County with people reporting anything from an explosion to a plane crash.  It is very likely that there will be more earthquakes in Bath County as the Earth continues is evolution and the tectonic plates deep underground stay in motion. The New Madrid Fault System has been the focus of concern for scientists and geologists since the massive quakes of 1811-1812; it is anticipated that another equally large or larger earthquake could, and statistically will, strike again.  With the dense population in the area now, the effects will be most certainly devastating.  Emergency officials throughout Kentucky have plans in their local operation plans for a large scale earthquake event if, or more appropriately when, it should happen. 

For further earthquake research go to: 

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