July 10, 2013
Have You Seen This Cessna? Low-Flying Plane Scans New Madrid For Geological Activity
Brett Smith for redOrbit.com - Your Universe Online
Folks living near the Mississippi River where Arkansas, Tennessee, Missouri and Kentucky converge should expect to see a low-flying, red-and-white Cessna today. Do not be alarmed, U.S. Geological Survey officials announced.
The region, known as the New Madrid seismic zone, is of particular interest to geologists and the federal agency is using low-level flights, being performed by specially trained pilots, to detect subtle local changes in the Earth's magnetosphere.
The Earth's magnetic field is correlated to rock formations that sit just below the surface of the land. Today's USGS flights are designed to detect subtle, hidden geologic features that could result in a better understanding of New Madrid's geology and hydrology. The survey may pick up small cloaked faults that could later give way to seismic activity.
"Faults sometimes bring together rocks with different magnetic properties," said Richard Blakely, the project leading USGS geophysicist. "These variations in magnetic properties produce very small magnetic fields that can be measured with low-flying aircraft, allowing us to map and characterize faults even though they may be completely hidden by vegetation or young sediments."
According to the USGS, this small corner of the Midwest has been the most seismically active area in the United States east of the Rocky Mountains. While experts are not predicting a catastrophic quake anytime soon, the USGS has voiced concerns about destructive seismic activity similar to the series of tremors that rocked the region in the winter of 1811-1812.
The early nineteenth-century quakes began during the pre-dawn hours of December 16, 1811 when a magnitude-9 tremor struck the region around what would become Memphis, Tennessee. Felt as far away as New York, the earthquake knocked chimneys to the ground and forced water back up rivers and creeks. An aftershock of similar magnitude hit northeast Arkansas about six hours later.
After countless small tremors and a couple of bigger ones, the final major event of this series of earthquakes struck New Madrid, Missouri on February 7, 1812, destroying the small town. This seismic event was also blamed for damage to houses in St. Louis and creating waterfalls in the Mississippi River.
In addition to this string of seismic events, geologists have found evidence of a sequence of 7- and 8- magnitude earthquakes that took place in the same region around 1450 AD, 900 AD and 2300 BC. These large earthquakes produced protracted and intense ground motions in the region where several million people live today, the USGS said in a statement.
The agency said the data collected from today's flight will take several months to a year until results can be analyzed and released. The USGS noted that the flights are being performed in collaboration with the Federal Aviation Administration to ensure public safety.
While they are not as well-known as their West Coast counterparts, Midwestern seismic zones have produced considerable activity in the past. On April 28, 2008, the Wabash Valley seismic zone unleashed a 5.2-magnitude earthquake near Belmont, Illinois. The fault zone is situated along the southern end of the Indiana-Illinois border.