Theron Finley

The Canadian Quaternary Association (CANQUA) Biennial Meeting is taking place at McGill University in Montreal, June 3-6, 2026.

Abstracts are due March 6th!
event.fourwaves.com/canqua2026/p...

If you work on geohazards, please consider submitting an abstract to our session:

This was a really fantastic team effort and it was fun to see it come together so fast in comparison to the usual pace of scientific writing (I guess we were excited!). More to come!

We also compiled a preliminary inventory of over 200 landslides along with other surface effects caused by the earthquake. Interestingly, despite there being some very large landslides, their areal distribution was considerably smaller than expected for an earthquake of this magnitude.

We applied double-difference relocation to the mainshock and 3280 aftershocks to illuminate the fault rupture geometry, and we explore the implications in terms of regional tectonics.

In response to the Dec. 6 Mw 7.0 earthquake in southwest Yukon, colleagues and I put together this short paper for the YGS's annual Yukon Exploration and Geology volume.

data.geology.gov.yk.ca/Reference/96...

Thanks for sharing this post - super interesting! We recently submitted a paper with a very similar theme, where we characterize a short fault scarp in the interior of the Canadian Cordillera. It's also a mature and slowly-deforming orogen with recent glaciation, making paleoseismology challenging!

Rock avalanche below Mt King George triggered by the 6 December 2025 Hubbard Glacier Earthquake. The runout distance is 1.4 km.

A sensational guest post by Derek Cronmiller, Theron Finley Panya Lipovsky and Jan Dettmer of the Yukon Geological Survey: Photos and Preliminary Observations from an Overview Flight of the 6 December 2025 Hubbard Glacier Earthquake, Yukon Territory, Canada.
eos.org/thelandslide...

We collected 100s of photos, hopefully enough to build rough 3D models with photogrammetry software. Good pre-event images may be hard to come by though

it’s certainly one benefit of living at this latitude. Days might be short but it’s golden hour all day!

It was a pretty incredible day at work this past Friday!

he first Sentinel1 images are in after the Alaskan M7 earthquake beneath Hubbard Glacier - no shortage of new landslides. Below are 28/11 and a 9/12 images! @watershedlab.bsky.social @davepetley.bsky.social

Thanks John :)

I was on CBC's Yukon Morning today speaking about Saturday's Hubbard Glacier M7.0 earthquake and its aftershocks.

Coincidentally, I got an audible alert on my phone for the M7.6 earthquake in Japan while we were on air!

www.cbc.ca/listen/live-...

Very preliminary relocation results from the December 6th #Alaska - #Yukon #earthquake, The Hubbard Glacier Earthquake. Double difference locations (343) derived from catalog epicentres (372), both manual and automatic. Squares are catalog epicentres, circles are relocations.

A USGS map of aftershocks (first 5 hours) show more than 60 located, some as large as M5.1. Coloured dots indicate the age of the events. These extend in a NW-SE direction along a 50-km-long fault.

Today's shallow M7 #earthquake near the Yukon-Alaska border has produced more than 60 #aftershocks (some as large as M5.1) during the first 5 hours.
Live #shaking from a seismic station at Haines Junction (YT) shows a steady stream of aftershocks:
www.earthquakescanada.nrcan.gc.ca/stndon/wf-fo...
⚒️🧪

A hypothesized fault connecting the Fairweather and Totshunda faults. It's evident in GNSS block models and seismicity patterns, but surface trace is obscured by the St. Elias icefield

Wow! 6.8 earthquake in Yukon near the border with Alaska! Shallow! Wondering if there is surface rupture? Or possibly landslides?

Pretty good shake here in Whitehorse. I didn’t feel it (I seemingly never do) but lots of other people did!

This is fantastic news!

Map showing extent of data coverage, primarily over southern Canada

A hillshade colored by elevation of downtown Toronto draped on Google Earth imagery.

A three panel figure of a section of the Athabasca River in Alberta. Figure A is the Digital Surface Model which includes buildings, trees and other structures. Figure B is the Digital Terrain Model and is a bare-earth representation of the topography. Figure C is the Canopy Height Model (CHM) which is the difference between the DSM and the DTM.

OpenTopography is excited to announce a major expansion to its international data catalog with the addition of the High Resolution Digital Elevation Model from Natural Resources Canada. This 1-meter resolution dataset is ideal for a wide range of applications.

opentopography.org/news/opentop...

Thanks Britta! I’m headed up in two weeks and also can’t wait. The Yukon is truly the best!

Glad you find it helpful, Jeff! Lots more work to do, now that we know this hazard exists.

Indeed! I'm always amazed at the prescience of previous researchers, and it's great to be able to prove some of these hypotheses now that we have better data (ArcticDEM and lidar). Mortensen and Von Gaza speculated about these lineaments back in 1992(!) in an somewhat obscure YGS report!

Certainly! The main point we were making here is that old, mature faults like this that were likely much more active in the past, and played a major role in the development of the Cordillera, still persist as crustal weaknesses and seismic hazards.

Yes, the majority of the Canadian landmass, including BC, was covered by ice during the last glaciation. The southern ice limit was in the northernmost United States. Only northwest Yukon (and broader region extending across northern Alaska) remained ice free.

Also, in the rest of Canada where the landscape is much younger, evidence of this sort of fault activity would be largely erased, highlighting a preservation problem in the paleoseismic record.

More broadly these results highlight the seismic hazard of mature, low‐slip‐rate intraplate faults in orogenic belts, which may have very long recurrence intervals and elude detection via instrumental networks.

Satellite imagery map showing Dawson City, the location of the Moosehide Slide immediately of town, and the location of the Sunnydale landslide west of town across the Yukon River.

For example, this figure from Bodtker et al (2022) shows the position of the Moosehide and Sunnydale landslides above Dawson City.

A large rupture on the Tintina fault would cause significant shaking in the Klondike region, potentially damaging buildings, highways, and mining infrastructure. Compounding the hazard from seismic shaking, the region is prone to landslides, which could be seismically triggered.

Notably, 12,000 year old landforms are not offset across the fault, which implies that it may be at a relatively late stage of an interseismic period, having accrued a slip deficit of ~6 m. From this, we estimate that ruptures of at least magnitude 7.5 are possible in the future.