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Engineering tsunamis
DISASTER PREDICTION: Queen’s civil engineering professors Ryan Mulligan and Andy Take are learning to predict how landslides and landslide-generated waves will behave.
O
n the evening of October 9, 1963, in the idyllic countryside just north of Venice, Italy, a 400-metre chunk of rock sheared off the side of Mount Toc and slammed into the reservoir behind the Vajont Dam. The dam held, but some 50 million cubic metres of water overtopped it, creating a 200-metre-high wall of fluid and compressed air that sped down the Vajont Valley. Whole villages were destroyed and some 2,000 people died.
It’s that kind of loss of life and destruction of infrastructure that Queen’s civil engineering professors Andy Take and Ryan Mulligan hope to mitigate through their research into landslides and the waves they cause. Mulligan, a coastal engineer who studies the behaviour of waves, and Take, a geotechnical engineer and landslide researcher, are combining their knowledge and skills to shed new light on the mechanics of landslidepropagated tsunamis. “We’re trying to figure out how much an individual landslide contributes to making that first wave,” says Dr. Take. “How big will that wave be for different water depths and different slide volumes?” “Tsunamis behave very differently
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THE COMPLETE ENGINEER
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depending on the bathymetry they go over or the different shorelines they hit,” says Dr. Mulligan. “A lot of problems
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Rather than seeing how big
a wave a short block of material will create, we can now produce model landslides with more realistic geometries.”
are site-specific, so trying to understand those types of problems more generally is really important.”
“When we’re looking at landslides there are two problems we’re investigating,” says Take. “One is the mechanics of triggering: What conditions do you need to get a landslide starting to move? The other is how far will it go once it’s moving? We have to understand both of those questions to understand risk.” To that end, Take oversees a 50-metrelong landslide flume at the Coastal Engineering Lab on the West Campus at Queen’s. The apparatus, which looks a bit like a log-slide ride, was built with funding from a Canada Foundation for Innovation grant and is used to simulate landslides, the waves they generate and the damage they can cause. The first
