Scientists are planning a “CAT scan” of a British Columbia volcano to help harness geothermal energy.
“Canadians are often surprised to know there are volcanoes in the country,” said Steve Grasby, a geologist with Natural Resources Canada, according to CTV News Canada. “But there are active volcanoes.”
Grasby and his crew are headed about 24 kilometers (15 miles) west of Whistler, B.C., to Mount Cayley, part of the same mountain chain as well-known volcanic peaks such as Mount St. Helens in Washington State.
Mount Cayley is an eroded but potentially active stratovolcano. Part of the Garibaldi Volcanic Belt, Mount Cayley was formed by subduction zone volcanism along the western margin of North America.
Eruptive activity began about 4,000,000 years ago and has since undergone three stages of growth, the first two of which built most of the volcano. The latest eruptive period occurred sometime in the last 400,000 years with lesser activity continuing into the present day.
The volcano towers over the Cheakamus and Squamish river valleys, where all of the summits tower over 2,000 meters (6,600 ft). Mount Cayley is the highest at 2,385 m (7,825 ft).
The surrounding area has been inhabited by indigenous peoples for over 7,000 years and geothermal exploration has taken place over the last 40 years. The Geological Survey of Canada (GSC) has been monitoring the volcano and its surroundings.
Cayley’s last lava flow was back in the 1700s, but plenty of heat remains. At nearby Mount Meager, a well drilled in the 1970s showed temperatures of 250 C at 1.5 kilometers depth.
That much heat at such a relatively shallow depth is a great opportunity for geothermal energy, said Grasby. “In terms of temperature, it’s a world-class resource,” Grasby said.
How will they tap that energy?
Geothermal plants generate power through the heat contained in underground water. Their success depends on sinking wells in just the right place to find the most water at the highest temperatures, according to Castanet.
Grasby says that because the drilling is so expensive, they are looking for very high success rates, like 50 percent or better, unlike oil and gas drillers that only need to be right one time out of seven.
So, to get the best possible outcome for the drill team, Grasby and his team are going to create a 3-D map of Mount Cayley, without using traditional tools such as seismic lines.
Part of the map will be drawn through basic geology. The team will analyze which rock types are present to find out how permeable or porous they are, and will also be locating and diagramming fault systems that may hold hot water.
But here is something surprising – They will also use methods such as examining how electromagnetic energy moves through the volcano. For example, when lightning strikes — even in a remote part of the world — the geologists can examine how that energy moves through the earth, where it is being absorbed, and where it passes through.
“We have to go all around the volcano, so you’re looking into it from all these different angles,” Grasby said.
“You can start to develop a 3-D image of what’s underground. By collecting these observations all around the volcano, you can start to see there’s a magma chamber at 10 kilometers depth or a hot fluid-filled reservoir at two kilometers.
In other words – Hoorah! – we have a CAT scan.
Canada is the only Pacific Rim country that does not have geothermal wells that are producing energy. It is not for ,lacvk of trying, though. ompanies in Saskatchewan and B.C. have drilled wells and a couple more have plans. Alberta has recently joined B.C. in developing a regulatory regime for geothermal development.
The energy source could be a significant zero-carbon contributor to Canada’s energy needs, Grasby said. “Until someone sees a producing geothermal well, it’s hard to believe it could be true. You need to see that first one,” he said.
