News Release No. 406

DEPARTMENT OF NATURAL RESOURCES RECORDS
EVIDENCE OF SUMATRA EARTHQUAKE IN MISSOURI

Volume 32-406

Contact: Jim Palmer

(For immediate release)

573-368-2182

ROLLA, MO, DEC 30, 2004- An earthquake off the west coast of Northern Sumatra was observed as far away as Missouri. According to the Department of Natural Resources, shortly after the magnitude 9.0 quake rocked the far east, shock waves reached Missouri causing fluctuations in groundwater levels as recorded in the water supply monitoring network wells around the state. The department's Geological Survey and Resource Assessment Division (DGLS) in Rolla operates a network of 73 groundwater-level observation wells located in about 50 Missouri counties that measure and record the depth to groundwater below land surface in many of Missouri's aquifers.

The earthquake, which occurred at about 6:58 PM Central Standard Time (CST) on Dec. 25, caused water levels to fluctuate in a number of the network observation wells. Most fluctuations were small, but the water level in the Aurora observation well in Lawrence County varied about 8 ½ inches. The fluctuating water levels did not pose a problem for Missourians; however, they are evidence of how large earthquakes can be tracked around the world in a short time period. To view the graph on the internet see: www.dnr.mo.gov/geology/geosrv/gdam/sumatranEQ.htm.

Missouri has its own risks caused by earthquakes in the New Madrid Seismic Zone in southeast Missouri. While tsunamis or earthquake-induced tidal waves are not a threat to Missouri, DGLS is working to provide adequate geologic data to Missouri's citizens so as to anticipate the other hazards posed by mid-continental earthquakes. Landslides, sandblows and liquifaction of alluvial materials are some of the natural hazards anticipated in our state.

Mimi Garstang, DGLS director and state geologist, explains, "We are collecting data that will be used to map and evaluate potential earthquake shaking hazards in developed and

growing areas of the southeastern region of our state. Engineers, planners and property owners will use these maps and data as tools to determine the measures necessary to protect human life and property. Sound scientific knowledge of where the risks are greatest will allow Missourians to be as prepared as possible in the event of a major earthquake in the New Madrid area."

Data from all of the observation wells can be viewed on the Internet at: www.dnr.mo.gov/water.htm. Under the "Monitoring" entry, then click on "Current Groundwater Conditions."

For news releases on the Web, visit www.dnr.mo.gov/newsrel. For a complete listing of the department's upcoming meetings, hearings and events, visit the department's online calendar at www.dnr.mo.gov/calendar/search.do.

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NOTE TO EDITOR: A graph related to this release is available online at: www.dnr.mo.gov/newsrel/samatEQ.jpg, Caption: Groundwater level hydrograph from the Aurora Observation well showing seismically--induced water level fluctuations. Graph: courtesy of Missouri Department of Natural Resources' Geological Survey and Resource Assessment Division