Veteran earthquake researcher Stephen Gao likes to stay close to the
A decade ago, Gao lived in southern California, one of the
world's most active earthquake zones, while completing a doctoral
degree in geology at the University of California, Los Angeles.
Gao joined the faculty of Kansas State University in 1999 as
assistant professor of geology.
Although Gao no longer lives and works in the shadow of
California's infamous San Andreas Fault, he continues to monitor
seismic activity in an unlikely place -- eastern Kansas' less-well
known Humboldt Fault Zone.
"Studying earthquakes here is not like looking for tornadoes,"
Gao said. "You don't go out and chase one down. But you can record
As Kansas' leading quake recorder, Gao has had plenty of
earthshaking news to send back to colleagues in California.
During the past six months, nearly 50 small "microearthquakes"
have been detected in the vicinity of the Humboldt Fault line and
neighboring seismic zones in the Sunflower state, Gao says.
"The majority of Kansas people have no idea about the earthquake
potential in this area," Gao said.
Most of the recent Kansas temblors probably went unnoticed by
humans, Gao says, and none measured above a 2.0 on the Richter
In comparison, last month's quake that caused significant
structural damage in the Pacific northwest registered a 6.2 on the
Richter scale, the standard scale for measuring earthquake intensity
since 1935, Gao said.
Kansas' Humboldt Fault is a 300-million-year-old subterranean
fracture in a vast plate of granite stretching from Nemaha County on
the north to Sumner County at the Oklahoma line.
In the Manhattan area, the Humboldt Fault is broken by series of
bisecting underground fissures, a possible explanation for a series
of recorded quakes that have topped out at 5.5 on the Richter scale
in Pottawatomie and Riley counties.
An 1867 temblor centered between Wamego and Manhattan cracked
plaster walls and demolished chimneys in both communities, while
knocking a horse to its knees in Louisville, according to newspaper
"In reality, we really have no idea about the current stress
field beneath us in Kansas," Gao said. "In California, maybe we can
have some idea because people spend millions of dollars studying the
San Andreas Fault. But here, we do almost nothing."
Geologists theorize that earthquakes erupt along fissures deep
within the Earth's crust, sending violent vibrations to the surface,
occasionally inflicting catastrophic damage to man-made structures,
while killing or injuring thousands of people.
Gao's recent Kansas quake data has been gathered by a network of
eight portable seismographs that were installed last summer
throughout northeast and north central Kansas, and funded by a
$46,000 grant from the National Science Foundation.
Last month, KSU's department of geology installed a new
permanently-mounted $40,000 seismograph on campus, funded by a
combination of public and private resource monies, Gao said.
Geologists at the Kansas Geological Survey office in Lawrence
estimate that the Humboldt Fault is capable of producing a
6.5-magnitude quake every 2,000 to 5,000 years, said University of
Kansas seismologist Don Steeples.
"In geologic time, that's a long period to wait for a return
event," Steeples said. "The fact of the matter is, we don't know
when the last 6.5 occurred. So the next one could be 10 years from
now, or in 10 days. In any case, it will be a major event, the
Kansas version of 'the big one.' "