CHICAGO — Despite the seemingly significant and frequent natural disasters since the Haitian earthquake in January 2010, experts say there is no connection between the earthquakes around the globe, major flooding in South America and volcanic eruptions in Iceland that have followed since.
“There’s no particularly worrisome or intriguing seismic activity,” said Emile Okal, professor of earth and planetary sciences at Northwestern University.
“The distribution of earthquakes is more or less random,” added Philip Carpenter, professor of geology and environmental science at Northern Illinois University.
According to the U.S. Geological Survey, on average, there are an estimated 15 earthquakes of a magnitude 7.0 each year. And experts say we have just come off a 40-year period that, if anything, had lower than expected activity levels.
“If you average seismic activity over long enough time, you would say that perhaps the 1960 to 2000 period had been a little deficient,” Okal said. “We hadn’t really had any major earthquakes since 1965.”
Okal said the reason for reduced activity remains unknown. But we do know that earthquakes are caused by movements in tectonic plates which lie underneath the earth’s surface. These plates move a few centimeters each year, buckling and deforming at the edges to pass one another but sometimes they snap, similar to a tire screeching on pavement when driving, which is when an earthquake occurs. Scientists can measure levels of deformation but they cannot predict if and when such a snap might occur.
The U.S. Department of Homeland Security, through the Federal Emergency Management Agency, considers natural disasters in the scope of national security. However, because these events are random and unpredictable agencies can only ensure emergency plans are prepared and ready for execution when needed.
In Illinois, April is Earthquake Preparedness Month, reminding residents they are situated by two active seismic zones; the New Madrid, located in the Central Mississippi Valley that extends to several neighboring states and the Wabash Valley, which stretches from southeastern Illinois to southwestern Indiana.
“We are within the most active earthquake area east of the Rocky Mountains,” said Patti Thompson, spokeswoman for the Illinois Emergency Management Agency.
Although the earthquakes would not affect residents of northern Illinois directly, the relocation of families and use of state resources in helping disaster victims would be felt state-wide.
“If we had a 7.7 major earthquake in the southern part of the state, as many as 17,000 homes could be totally destroyed with another 25,000 to 30,000 that could be damaged,” Thompson said.
The largest earthquake in the continental United States occurred in the New Madrid zone in the winter of 1811- 1812. There has been activity on this line since but the quakes have hovered around the magnitude 5.0 range, meaning little damage was caused. There is very little evidence of deformation in the zone but scientists are still actively monitoring the area to better understand if that really means an earthquake is not likely occur in the region.
IEMA estimates that a serious earthquake in the New Madrid zone could result in $60 to $80 billion of damage.
“It is advisable to prepare for the earthquakes,” said Carpenter of Northern Illinois University, “because it’s impossible to make a prediction.”
