Volcanoes in Canada, eh? - USGS Volcano Watch

Happy Canada Day/Bonne Fête du Canada! While some past "Volcano Watch" articles have had a July 4th theme for the USA, this year we’re taking the opportunity to ensure readers know that our neighbors to the north have volcanoes, too—including potentially active ones. On the Island of Hawaiʻi, residents are well acquainted with active volcanoes like Kīlauea and Mauna Loa, and have likely also heard about other volcanoes on the US mainland, including Mount. St. Helens and Yellowstone. Many people may not realize it, but the same chain of volcanoes—the Cascade Volcanic Arc—that includes volcanoes such as Mount Rainier, Mount St. Helens, and Lassen Peak along the west coast of the US extends up past the Canadian border. Volcanoes don’t care about international boundaries! The Garibaldi Volcanic Belt (GVB) is the (mostly) Canadian extension of the Cascades, and includes Mount Garibaldi, Mount Cayley, and Mount Meager in Canada, and Mount Baker and Glacier Peak in the US. Closest to the US-Canada border, municipalities just south of Vancouver, British Columbia, sit on deposits from Mount Baker, located in Washington State. So, while the volcano itself is in the US, were it to erupt, the area near Vancouver could still be affected by hazards like mudflows and ash fall. North of Vancouver, and unlike many of their cousins to the south that are conical stratovolcanoes, the Canadian volcanoes of the GVB are complex mountains composed of all sorts of volcanic features, many of which have been eroded by glaciers. Mount Meager had the GVB’s most significant recent eruption—only about 2,400 years ago, it experienced an eruption very similar to the 1980 eruption of Mount St. Helens, complete with an ash plume, a lava flow, and pyroclastic flows. But just because the volcanoes in the GVB haven’t erupted for many years doesn’t mean they can’t erupt again—Mount Meager has hot springs and emits volcanic gases including carbon dioxide and hydrogen sulfide, indicating the persistence of magmatic heat. A small seismic swarm occurred in 2014–2015 to the south of Mount Meager as well. Further north in the province of British Columbia and into the Yukon is where Canada’s more recent volcanism has occurred, at volcanoes such as Mount Edziza, the Alligator Lake Volcanic Complex, and others. Many of those eruptions were of basaltic lava, so they would have looked very familiar to those of us in Hawaiʻi. Around the year 1700, Tseax Cone in the Northern Cordilleran Volcanic Province (NCVP; formerly the Stikine Volcanic Belt) underwent a period of volcanic activity with large outpourings of lava. The nearby Nisga’a First Nations community was devastated by the eruptions. At least two villages were destroyed by the flows, and gases from the volcano killed potentially up to 2000 Nisga’a people. The eruption is thought to be Canada’s deadliest geological disaster. More recently, only about 150 years ago, Lava Fork Volcano—also in the NCVP—produced Canada’s most recent documented volcanic eruption. Lava flowed from the volcanic cone and across the Alaska border, where it blocked the Blue River. The eruption is not known to have been witnessed, but the flows have been mapped and dated. Similar to what we see at Hawaiian volcanoes, pāhoehoe lava erupted from both Lava Fork and Tseax Volcanoes and created many lava tubes and even tree molds. There were reports from miners of an even more recent eruption in November of 1898 at Ruby Mountain in the NCVP—the New York Times even published the news!—but no geologic evidence of the eruption was ever found. In 2007, Nazko Cone, the easternmost volcano in the Anahim Volcanic Belt, and one which hadn’t erupted in about 7200 years, suddenly experienced a swarm of over 800 microearthquakes in three weeks. Hawaiian volcanoes often have many earthquakes, but the area near Nazko Cone had never had any recorded earthquakes before. The swarm was interpreted to be caused by an injection of new magma into the lower crust. Though Nazko didn’t end up erupting in 2007, and nothing else in Canada has erupted for over 100 years, there are many volcanoes that could still erupt there in the future. If and when an eruption does occur, it’ll surely be a new phenomenon for Canadians—they don’t quite have experience living with volcanoes that those of us in Hawaiʻi do! For additional information on volcanoes in Canada, see https://chis.nrcan.gc.ca/volcano-volcan/index-en.php IMAGE CAPTION: At left, a map of select recent volcanoes and volcanic areas in Canada (volcano location data from: Global GIS: volcanoes of the world; volcano basic data. [Shapefile]. American Geological Institute. Retrieved from https://earthworks.stanford.edu/catalog/harvard-glb-volc). Right top, Eve Cone, a cinder cone in the Mount Edziza Volcanic Field in Northern British Columbia, Canada (photo courtesy Ben Edwards, Dickinson College). Right bottom, a cinder cone formed in 2018 at Fissure 22 of Kīlauea's 2018 eruption, appearing almost identical to Eve Cone despite the very different locations of the two cones (USGS photo).