John Cassidy
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earthquakeguy.bsky.social
John Cassidy
@earthquakeguy.bsky.social
5.4K followers 880 following 1K posts
NRCan earthquake seismologist + University of Victoria Adjunct Professor. Works with engineers, emergency managers, and communities to help minimize the impact of #earthquakes. Also, posts on Nature and Gardening (Zone 9a). 🌱 🧪⚒️ 🏞 🇨🇦
My thoughts/posts.
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earthquakeguy.bsky.social
How rare was last night’s widely felt southern #Ontario M3.7 earthquake?
Not unheard of, but rare! Typically only 2-3 earthquakes of M>2.5 are located in southern Ontario each year and an #earthquake of this size occurs every decade or so.
See:
www.earthquakescanada.nrcan.gc.ca/zones/eastca...
⚒️🧪🇨🇦
Seismograms showing ground shaking from the January 27, 2026 M3.7 earthquake located 100 km north of Toronto. Map of southern Ontario showing the location of the 27 January, 2026 M3.7 earthquake located 100 km north of Toronto. Coloured dots show how ground shaking was felt (weak to light shaking) across the region (to distances of more than 300 km).
January 28, 2026 at 7:36 PM
earthquakeguy.bsky.social
Thanks, yes, a M3.7 (or slightly larger) near Orillia, ON at 11 p.m. EST. Felt across southern Ontario.
www.earthquakescanada.nrcan.gc.ca/recent/2026/...
January 28, 2026 at 4:53 AM
earthquakeguy.bsky.social
Do you want to learn about the impacts of the M9 Cascadia subduction #earthquake that struck at 9 p.m. on this night, 326 years ago? Strong shaking, a tsunami and landslides as described in Indigenous oral traditions from #VancouverIsland to #California. ⚒️🧪
hakaimagazine.com/features/gre...
January 27, 2026 at 12:53 AM
earthquakeguy.bsky.social
326 years ago tonight (9 p.m. Jan. 26, 1700) a M~9 Cascadia subduction earthquake rocked the west coast from #VancouverIsland to northern California. The Juan de Fuca Plate slipped up to 20 m, causing a large tsunami, strong shaking and landslides
www.earthquakescanada.nrcan.gc.ca/historic-his...
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Colourful map showing the tectonic plates of the Cascadia subduction zone from Northern California to northern Vancouver Island. Cartoon map showing the tectonic setting of the Cascadia subduction zone, where the Juan de Fuca plate slips beneath the North American Plate from California to northern Vancouver Island.
January 26, 2026 at 4:13 PM
earthquakeguy.bsky.social
Pansies look huge if you get close enough to them...
#WinterGarden
#VancouverIsland
🇨🇦🌱📷
Close-up of red pansies in the garden. Green leaves and a beige house in the background.
January 25, 2026 at 11:51 PM
earthquakeguy.bsky.social
A perfect winters day on southern Vancouver Island 🇨🇦. Sailboats in the Salish Sea with the snow-capped #volcano Kweq'Smánit (Mt. Baker) off in the distance...
#Victoria
📸 🌋
Sailboats in the blue Salish Sea, a rocky landscape behind, a snow-capped volcano in the distance and blue skies above. View from Oak Bay on southern Vancouver Island.
January 25, 2026 at 1:13 AM
earthquakeguy.bsky.social
This is a great opportunity for graduate students at a #Canadian university:
www.oceannetworks.ca/science/scie...
Apply by January 31, 2026
Learn more about the research and legacy of Dr. Roy Hyndman in this Canadian Journal of Earth Sciences special issue:
cdnsciencepub.com/doi/10.1139/...
🇨🇦🧪⚒️🌊
oceannetworks.ca Ocean Networks Canada @oceannetworks.ca · 15d
📣 Calling all #Canadian grad students 📣

Receive $20,000 to support your research using ONC's ocean data!

Apply for the Roy Hyndman Ocean Observing Award by 31 January 2026 🌊 bit.ly/3rI4gHP

#CdnSci #SciSky
January 21, 2026 at 4:29 PM
earthquakeguy.bsky.social
A little glimpse of the Northern Lights tonight in the backyard...
#VancouverIsland
Green and a little red of the northern lights... large Douglas Fir trees also in the photo.
January 21, 2026 at 7:03 AM
earthquakeguy.bsky.social
January 9, 1982 - a rare, M5.7 #earthquake in the Miramichi region of #NewBrunswick. It was felt across Atlantic Canada, parts of #NewEngland and southern Québec and was followed by many aftershocks.
Details:
earthquakescanada.nrcan.gc.ca/historic-his...
Some news footage:
cbc.ca/news/canada/...
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Map showing the felt shaking intensities of the Jan. 9 1982 M5.7 New Brunswick earthquake. It was felt across Atlantic Canada, much of New England, and parts of southern Québec. The largest aftershock (M5.1) occurred on January 11, 1982.
January 9, 2026 at 4:48 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
To wrap up this series - 2025 was a fairly typical year for #earthquakes in Canada (the M7 was an ~decadal event). More than 5000 were recorded from coast to coast to coast, ~75% of those occurred on/near plate tectonic boundaries in western #Canada.
Thanks for following!
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Map showing earthquakes located in or near Canada during 2025.
January 6, 2026 at 12:46 AM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Canada's largest earthquake of 2025? M7 in southwest Yukon on Dec. 6th (the largest in #Canada since 2012):
www.earthquakescanada.nrcan.gc.ca/recent/2025/...
No damage/impacts due to the remote location, but felt across southern Yukon and southeast Alaska.
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Map of southwest Yukon showing the location (yellow dots) of the largest aftershocks of the Decemebr 6, 2025 M7 earthquake. This map does not show the 1000+ small aftershocks, that continue today.
January 5, 2026 at 3:52 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Are you hoping to dodge #earthquakes in #Canada?
Either #Saskatchewan or #Manitoba is the place to be. No earthquakes were located within this elliptical area during 2025 - this is always one of the most seismically quiet parts of the country.
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Map of Canada showing earthquakes located during 2025. No earthquakes were located in the area of Saskatchewan and Manitoba (marked by a red ellipse) during the year.
January 4, 2026 at 9:52 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025 - the “Earthquake Streak”.
In a time span of less than 3 weeks (Feb. 13 to March 5 2025), five #earthquakes (M2.5-4.6) were felt in Victoria, BC. Several of these were felt across much of SW BC. Some were shallow, some were deep (~60 km) and all were on different faults!
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Map of southwestern British Columbia showing the location of the five earthquakes that were felt in Victoria, BC over a time window of 20 days in 2025.
January 4, 2026 at 1:05 AM
earthquakeguy.bsky.social
Cordova Bay Beach is missing,
the day that earth is closest to the sun. The tide is high...
#KingTides
🧪📷🇨🇦
Photo of Cordova Bay Beach during a king tide. Blue water, logs and sand on a very narrow beach. and blue skies with a few white clouds.
January 3, 2026 at 10:43 PM
earthquakeguy.bsky.social
How many earthquakes occurred within 100 km of your Canadian community in 2025?
Here is a partial list - ranging from 0 #earthquakes near Winnipeg to 630 near Daajing Giids, Haida Gwaii.
The "top 3" are the same as in previous years.
Search the database:
earthquakescanada.nrcan.gc.ca/stndon/NEDB-...
Table listing the number of earthquakes recorded within 100 km of select Canadian communities in 2025. The magnitude of the largest earthquake within 100 km is also provided.
January 2, 2026 at 7:50 PM
earthquakeguy.bsky.social
Seismic waves from today’s (Jan. 2 at 05:58 a.m. PST) M6.5 #earthquake in Guerrero, #Mexico have rolled across Canada. It was located ~75 km from Acapulco and felt to distances of ~700 km.
Servicio Seismica Mexicano:
www.ssn.unam.mx/english/seis...
USGS:
earthquake.usgs.gov/earthquakes/...
⚒️🧪
Seismogram showing seismic waves from the 2 January, M6.5 earthquake near Acapulco, Mexico as recorded in Victoria, Canada (4130 km distant).
January 2, 2026 at 3:28 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Southwest #BritishColumbia - #Canada's seismic hotspot where tectonic plates collide. During 2025, 1315 #earthquakes (M0.1-5.0) were located here. 17 were felt and most were offshore along the active faults.
More:
www.earthquakescanada.nrcan.gc.ca/pprs-pprp/pu...
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Map showing the location of the 1315 earthquakes recorded in the southwest British Columbia region during 2025. Most were offshore and the largest was M5.0. A fairly typical year.
January 2, 2026 at 1:21 AM
earthquakeguy.bsky.social
And there it is… Canada’s first felt #earthquake of 2026 - in a region that doesn’t have earthquakes so often!
This M2.0 earthquake (at 11:19 EST today) occurred 32 km south of Windsor, #ON and was felt by many.
Details and to report shaking:
www.earthquakescanada.nrcan.gc.ca/recent/2026/...
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Map of southwest Ontario showing how today's M2.0 earthquake was felt in various nearby communities.
January 1, 2026 at 11:48 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
The Haida Gwaii region is one of Canada's seismic hotspots. During 2025, 1248 #earthquakes (M0.7-4.8) were located here (few were felt). Note that several M7-8 earthquakes have occurred here during the past 100 years.
www.earthquakescanada.nrcan.gc.ca/historic-his...
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A map of western Canada showing the 1248 earthquakes located in the vicinity of Haida Gwaii during 2025. The largest earthquake was a M4.8 earthquake located offshore, to the south of Haida Gwaii.
January 1, 2026 at 10:38 PM
earthquakeguy.bsky.social
For my gardening friends... a change of topic. It's a new year, and the first of the new winter #flowers are blooming on southern #VancouverIsland - Hellebores.
🌱🇨🇦
Pink and white Hellebores blooming on January 1 on southern Vancouver Island. Green bushes and a gravel path in the background.
January 1, 2026 at 8:58 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Next up - the Charlevoix region of #Québec - the seismic hotspot of eastern Canada
During 2025, 314 #earthquakes (M0.0-2.9) were located here. Several were felt. It is worth noting the history of large (M~6-7) earthquakes here
www.earthquakescanada.nrcan.gc.ca/zones/eastca...
Map showing the location of the 314 earthquakes in the Charlevoix seismic zone during 2025. Most occurred beneath the St. Lawrence River in a zone between Baie-Saint-Paul and La Malbaie, Quebec.
January 1, 2026 at 8:37 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Next up - southern #Nunavut
During 2025, 115 #earthquakes of M1.0-4.9 were located in this region. None were reported felt, but it is worth noting that large (M~7) earthquakes have occurred here in the past (e.g., in 1933) ⚒️🧪🇨🇦
www.earthquakescanada.nrcan.gc.ca/historic-his...
Map showing locations of the 115 earthquakes located in Nunavut during 2025. Most were located in the vicinity of northern Baffin Island.
January 1, 2026 at 5:41 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
#Yukon and western Northwest Territories (a region of active plate tectonics and major faults like the Denali) is one of the most seismically active regions of #Canada. During 2025, 690 #earthquakes (including Canada’s largest of 2025 (M7) and 10 M>5) were located here. ⚒️🧪🇨🇦
A map showing the location of the 690 earthquakes located in the Yukon and Western Northwest Territories during 2025. Earthquakes are shown as dots, scaled by magnitude and colours indicate more recent events. This does not include the 100's of aftershocks of the M7 earthquake.
December 31, 2025 at 9:34 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
Eastern #Ontario and western #Québec - a seismic hotspot in eastern Canada. 196 #earthquakes (M0.0-3.6) were located here in 2025 - a typical year. Only eight were felt.
This area also has a history of large earthquakes:
www.earthquakescanada.nrcan.gc.ca/zones/eastca...
⚒️🧪🇨🇦
Map showing the location of the 196 earthquakes located in West Quebec and Eastern Ontario during 2025. The largest earthquake was magnitude 3.6.
December 31, 2025 at 7:09 PM
earthquakeguy.bsky.social
Canada's Quakes of 2025
New Brunswick and Nova Scotia are (most of the time) seismically quiet. During 2025, 126 #earthquakes occurred in these #Atlantic provinces. The largest was M2.4 in central NB. A typical year - see zones 4/5 in:
www.earthquakescanada.nrcan.gc.ca/pprs-pprp/pu...
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A map showing the 126 earthquakes located in/near New Brunswick and Nova Scotia during 2025.
December 31, 2025 at 5:29 PM