{"id":520447,"date":"2026-03-07T13:16:08","date_gmt":"2026-03-07T13:16:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/520447\/"},"modified":"2026-03-07T13:16:08","modified_gmt":"2026-03-07T13:16:08","slug":"powerful-yukon-earthquake-sheds-light-on-changing-seismic-risk","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/520447\/","title":{"rendered":"Powerful Yukon earthquake sheds light on changing seismic risk"},"content":{"rendered":"

Open this photo in gallery:<\/a><\/p>\n

Jeremy Gosselin and his team at the Geological Survey of Canada map soil rigidity near a baseball diamond in Haines Junction, Yukon.Jeremy Gosselin\/Supplied<\/p>\n

On the morning of Saturday, Dec. 6, Jan Dettmer was working on the construction of his new house in Whitehorse, Yukon, when the concrete slab beneath his feet began to shake.<\/p>\n

Dr. Dettmer, who is the geoscience research manager for the Yukon Geological Survey, instantly knew it was an earthquake. It took only a second more to realize it was the biggest he\u2019d ever experienced in his life.<\/p>\n

\u201cI actually went under a table,\u201d Dr. Dettmer said. \u201cYou never know what\u2019s going to happen.\u201d<\/p>\n

Fortunately the only thing that fell over was a sheet of plywood. <\/p>\n

Ottawa launches consultation with insurance sector on earthquake costs, homeowner coverage<\/a><\/p>\n

Elsewhere in Yukon, damage was minimal and people escaped harm, in large part because the epicentre of the earthquake was 250 kilometres west of Whitehorse, under an ice-covered mountain range near the Alaska border. <\/p>\n

But it was a fearsome event all the same. Registering a magnitude 7.0, it was the Canada\u2019s largest land-based earthquake in over 75 years.<\/p>\n

Three months later, scientists are piecing together what they learned from the quake and the more than 4000 aftershocks that have continued to rattle the Yukon landscape since then. <\/p>\n

The key takeaways include a glimpse at the region\u2019s complex geology and a growing awareness that Yukon could be subject to a new form of seismic risk tied to permafrost thaw.<\/p>\n

There are two large fault systems in the region of the Dec. 6 quake. One is the Fairweather fault, which runs along the Pacific coast. The second, called the Denali fault, is located further inland. <\/p>\n<\/p>\n

For decades, researchers have speculated about the possibility of a \u201cconnector\u201d fault running between the two systems. Such a connector could be absorbing energy created by a fragment of ocean crust called the Yakutat microplate being forced underneath the North American continent.<\/p>\n

But proving the connector fault exists is not easy because the entire region consists of glaciers and rugged mountains.<\/p>\n

\u201cEverything is under ice up there. It\u2019s really hard to see things,\u201c said Julie Elliott, a geophysicist and research professor at Michigan State University. <\/p>\n

Dr. Elliott is among the scientists who regularly track minute changes in the positions of geographic benchmarks in the region to try and better understand how the crust is responding to geological forces. <\/p>\n

When the earthquake happened on Dec. 6, she was especially interested to learn that its epicentre falls exactly on the line of the hypothesized connector fault. <\/p>\n

Like a bright light switched on in a dark room, the quake and its aftershocks have helped to reveal a portion of the hidden fault, she said. <\/p>\n

In a separate analysis<\/a>, researchers with the Yukon and Canadian geological surveys showed that the aftershocks are clustered in two distinct groups. <\/p>\n

One group follows the path of the probable connector fault. The second lies along a separate plane that appears to indicate the existence of another structure, called a conjugate fault, running at a 60-degree angle to the connector.<\/p>\n

All of this is useful information for helping to determine what to expect the next time an earthquake rocks the region. <\/p>\n

\u201cOne major question is what the structure of the connector fault might be as you continue north, and how that might change as the plate motions change,\u201d Dr. Elliott said.<\/p>\n

Open this photo in gallery:<\/a><\/p>\n

Mr. Gosselin fixes a Natural Resources Canada (NRCan) seismic station.Jeremy Gosselin\/Supplied<\/p>\n

The data also offer a glimpse at the kind of energies that may be involved when an earthquake sweeps through the region. In another study led by Jeremy Gosselin<\/a> of the Geological Survey of Canada, researchers examined the potential for local amplification of seismic waves near Haines Junction, one of the communities that was nearest to the Dec. 6 quake.<\/p>\n

The concern is that earthquakes can deposit energy in very uneven ways, so that places that are far from the epicentre still experience severe shaking. This can be a risk whenever seismic waves move from rigid to loose soil and suddenly deposit a lot of energy in one place.<\/p>\n

Why this now matters in Yukon is that climate change is thawing permafrost in many areas, creating these kinds of abrupt changes in the stiffness of soil. <\/p>\n

\u201cWe\u2019re finding that thawing permafrost is adding an extra layer of complexity,\u201d said Dr. Gosselin. In the future, this change may need to be reflected in building codes.<\/p>\n

For his part, just experiencing the earthquake first-hand was a revelation, said Dr. Dettmer.<\/p>\n

\u201cIt\u2019s a good reality check that makes you understand how people might feel in a serious situation.\u201d <\/p>\n","protected":false},"excerpt":{"rendered":"Open this photo in gallery: Jeremy Gosselin and his team at the Geological Survey of Canada map soil…\n","protected":false},"author":2,"featured_media":520448,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-520447","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/520447","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=520447"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/520447\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/520448"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=520447"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=520447"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=520447"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}