ALEXANDRIA, VA. -- In the winter of 1811-1812, at least three great earthquakes struck
the central United States with magnitudes of 8.1, 7.8, and 8.0. Church bells rang as far away
as Richmond, Va., and people in New York City felt the ground shake. These were not the
first major earthquakes in the quad-state region of Missouri, Arkansas, Kentucky, and
Tennessee and according to seismologists, they will not be the last. In
the May issue of
Geotimes, Roy Van Arsdale, a neotectonics specialist from the University of
Memphis, discusses current research on the New Madrid seismic zone in his article, "Hazard
in the Heartland."
"A magnitude 8 New Madrid earthquake today would wreak havoc on interstate
highways, railroads, Mississippi River shipping, and lifelines -- and on cities such as
Memphis and St. Louis," says Van Arsdale. Studies suggest a recurrence interval of 450
years between earthquakes large enough to produce surface faulting and liquefaction.
Identifying the role of the Reelfoot fault, the most seismically active part of the system, will
help gauge the likelihood and effects of future seismic activity in the area. "The area is one
of the best instrumented and studied seismic zones in the world -- one that can be viewed as
a type section for intraplate earthquakes," says Van Arsdale. "What we learn in the New
Madrid zone should help us understand areas like Charleston, S.C., and the St. Lawrence
Seaway."
The art of war has given birth to many technologies that have been adapted to
civilian life. In his article, "Unmanned Aerial Vehicles That Even Geoscience Departments
Can Afford," Jonathan E. Nyquist, a research geophysicist at Oak Ridge National
Laboratory, discusses recent adaptations of unmanned aerial vehicles (UAVs), originally
developed for military purposes and a military budget. Researchers at Oak Ridge National
Laboratory loaded model airplanes designed for the weekend hobbyist with enough hardware
and software to shoot high-quality aerial photographs. As the technology improves and the
equipment becomes smaller, Nyquist sees a wealth of possible geologic uses for UAVs --
taking aerial photographs for geologic mapping, collecting gas samples from volcanoes,
identifying formation contacts, and collecting magnetic and electromagnetic data for mineral
exploration. "There is no reason that the next generation of smaller and cheaper UAVs
shouldn't be a part of the geoscientist's toolbox," says Nyquist.
In a third feature article, "Responsible Mining: Environmental Management at
Grasberg," Mark Cloos, a professor at the University of Texas at Austin, discusses the
efforts of the mining company, Freeport Indonesia, to safely dispose of mill tailings and to
control sheetwash events at the Grasberg mine in Irian Jaya, Indonesia. The discovery of
large reserves of copper and gold ore has increased production levels at the Grasberg mine
and is extending its lifespan into the next century. But such operating levels put a greater
stress on the sensitive landscape of this remote region. Responding to these challenges,
Freeport Indonesia has created an environmental laboratory that monitors water and tissue
samples and developed engineering solutions to potential flooding problems.
Geotimes is published by the American Geological Institute, a nonprofit
federation of 31 member societies representing geologists, geophysicists, and other earth and
environmental scientists.
