Analysis of Evacuation Routes of St. Louis Area in Event for Major Earthquake

    By Kathleen Berger, Executive Producer for Science and Technology

    For decades, experts have warned that a large swath of the central U.S. is at risk for a devastating earthquake produced from the New Madrid Fault Line. The St. Louis region has two seismic zones, including the New Madrid Fault Line, which last caused a series of major earthquakes more than 200 years ago. 

    Three magnitude 7.5 to 7.7 earthquakes rang church bells as far away as South Carolina and briefly caused the Mississippi River to flow backward. And experts say there’s up to a 10% chance a major earthquake could happen again within the next 50 years.

    “Scientists say every day that we’re closer to an earthquake, but they can’t plan for when that date is,” said Michael White, Emergency Management Coordinator for Missouri Department of Transportation.

    According to FEMA, a magnitude 7.7 earthquake in the New Madrid zone could displace nearly 850,000 people in up to eight states including people in the St. Louis area.

    “If you look at electricity, power,” explained White. “Injuries, and the hospitals are impacted, we (St. Louis area) may have 250,000 to 350,000 evacuees.”

    So MoDOT launched a study focused on forming evacuation routes for St. Louis metro in the event of a major earthquake. This is accomplished by partnering with the University of Missouri College of Engineering, as St. Louis is considered a challenging location.

    “The number of river crossings and how much traffic those roadways carry, I-70, 270, and all of those corridors. So that’s a big challenge,” said Praveen Edara, PhD, Professor and Chair of Civil and Environmental Engineering at the University of Missouri. “The other is the proximity to the Wabash Valley Seismic Zone, in addition to the New Madrid, and some of the buildings that are historic. They may not have been designed to the current standards.”

    Funding from MoDOT will provide software for the Mizzou engineers to see how roads, bridges and other infrastructure might be impacted by a major earthquake. They will use U.S. Geological Survey (USGS) ShakeCast data to build simulation models to evaluate various roads and bridges in the event of a large earthquake.

    “We request data for varying severity levels starting from a 5.0 magnitude to all the way to 7.0.,” said Edara. “We do look at how we load the demand. Is everyone leaving right away? Or is 20% leaving in the first few hours, then the remaining 20%? And so on.”  

    It’s expected emergency aid would be cut off.

    “Identify alternative routes and how best to move people in and out,” said White.

    The project involves several steps over a two-year period. The research team completed the first step, a survey of St. Louis area residents. The survey asked residents which routes they would take to evacuate.

    “Primarily saying that they’ll stick with the interstates. So I-70, 270, 55, the major interstate system,” said Edara.

    The research team will assess bridge structures along those routes using National Bridge Inventory (NBI) data that will be added to the data from different pieces of the project.

    “It will be combined into a network model or a traffic simulation model that routes evacuees,” said Edara. “There’s been a lot of progress made in transportation engineering. These models wouldn’t have been possible maybe 15, 20 years ago. So, all the computational advances are what makes it easier today to even think of assigning such high traffic volumes and come up with reasonable estimates of how the road network will look like under different earthquake scenarios.”

    “We’re looking at the engineering and upgrades for the bridges,” said White. “I think one key planning piece for us is accessibility across state lines, probably planning that those bridges are impacted. So, we’re really planning to bring everybody to the west. Kansas City and Springfield will be key reception centers for evacuees.”