Queen's Engineers work to mitigate disaster

Posted on November 05, 2015

Mulligan and Take study landslides and the tsunamis they can cause

 Ryan Mulligan and Andy Take

DISASTER PREDICTION: Queen’s Civil Engineering Profs Andy Take and Ryan Mulligan are learning to predict how landslides and landslide-generated waves behave before they happen.

On 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 landslide-propagated tsunamis.

“We’re trying to figure out how much of an individual landslide contributes to making that first wave,” says Take. “How big will that wave be for different water depths and different slide volumes?”

“Tsunamis behave very differently depending on the bathymetry they go over or the different shorelines they hit,” says Mulligan. “A lot of problems are site-specific, so trying understand those types of problems more generally is really important.”

To that end, Take oversees a 50 meter long 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 through funding earned through a Canada Foundation for Innovation grant and is used to simulate landslides, the waves they generate, and the damage they can cause. Take says the 8 metre-long portion of the flume inclined at 30 degrees, enabling researchers to build more realistic landslides which accelerate into the reservoir.

Landslide Flume

BUILDING AN UNDERSTANDING: Graduate students Alanna Carreira and Gemma Bullard configure instrumentation in the 50-metre landslide flume at the Coastal Lab at Queen’s.

“It will lead to better predictive models of landslide risk,” he says. “Rather than seeing how big a wave a short block of material will create, we can now produce model landslides with more realistic geometries.”

This work will help engineers place and design structures to minimize damage and, more importantly, loss of life when landslide disasters, like the one that killed so many in Italy all those years ago, strike populated areas.

“We’re always trying to understand how nature works so we can build better and safer structures or understand erosion better,” says Mulligan. “We want to know where to build buildings, where not to build buildings, and how to stabilize slopes so infrastructure and lives are saved.”