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John Cassidy

@earthquakeguy.bsky.social

5.2K followers 840 following 820 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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John Cassidy @earthquakeguy.bsky.social · 2h

Thank you. It sure is too short...

John Cassidy @earthquakeguy.bsky.social · 2h

Thank you - yes, such a sad day, and a huge gap to deal with.

John Cassidy @earthquakeguy.bsky.social · 2h

Thank you.

John Cassidy @earthquakeguy.bsky.social · 2h

Oh Winston, our hearts are broken. We are so grateful for the 15+ years that you spent with us. Thank you for the many (many!) 1000's of walks and hikes. Thank you for always being there and for always watching out the window for our return, then greeting us at the door. Miss you forever
#Dogs
#Love

Photo of a young Winston, our black, white and tan English setter, sitting out on the deck. Green grass in the background.

Photo of Winston, at about 5 years of age, relaxing on a lounge chair on the deck, soaking up the sun.

A close-up photo of Winston lying on the carpet, relaxing.

Photo of a 15+ year-old Winston sitting on his brown chair in the window watching for our return.

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John Cassidy @earthquakeguy.bsky.social · 3d

It is nice to see the tall, pampas grass plumes return. They are beautiful - until the rains begin in November! Enjoy while they are here...
🌱📷

Photo of tall, white plumes of pampas grass. Green leaves below, and a tall green cedar tree behind.

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John Cassidy @earthquakeguy.bsky.social · 9d

Great question! I didn't know until this year...
They look like watermelons but are about the size of your thumb. They taste like a cross between a pickle and a cucumber. Very tasty!

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John Cassidy @earthquakeguy.bsky.social · 9d

September may be winding down, but my #VancouverIsland garden sure isn't! Just picked - green beans, yellow beans, cucumbers, beets, snap peas, cucamelons, apples, lemons and tomatoes... so many tomatoes! Lots of kale, spinach, arugula and lettuce planted for the Fall and Winter. 🌱🇨🇦

Photo of fresh-picked tomatoes, beets, yellow and green beans, cucumbers, apples, lemon, snap peas and cucamelons ( that look like tiny watermelons).

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John Cassidy @earthquakeguy.bsky.social · 15d

Great question! I don't know, but will try to find the answer! It could be that it indicates a "significant" or "protected" tree.

John Cassidy @earthquakeguy.bsky.social · 15d

On #VancouverIsland you don't have to go far to find trees that are perfect for #ThickTrunkTuesday
This is a large Douglas Fir in #Victoria. 🌱📸🌲
#Photography
#Trees
#Canada

Photo of a large Douglas Fir tree on southern Vancouver Island.

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John Cassidy @earthquakeguy.bsky.social · 18d

For my friends in #Washington #Oregon and northern #California - a great summary of #earthquake hazards and probabilities for the three types of earthquakes in #Cascadia has been released by the USGS:
pubs.usgs.gov/publication/...
note that this also applies to southern #BritishColumbia.
⚒️🧪

USGS Publications Warehouse

Earthquakes and their cascading consequences pose a significant threat to the people, environment, infrastructure, and economy of the U.S. Pacific Northwest. The Pacific Northwest is susceptible to th...

pubs.usgs.gov

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John Cassidy @earthquakeguy.bsky.social · 18d

It is great to see you back here!

John Cassidy @earthquakeguy.bsky.social · 19d

Thanks - you are absolutely right! These are aftershocks of the July, 2025 M8.8 earthquake. That was a "megathrust earthquake" - the world's largest type of earthquake that can produce large aftershocks, over a large area, for a long time (for several years). So not an unexpected aftershock sequence

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John Cassidy @earthquakeguy.bsky.social · 19d

Seismic waves (not felt) from today's M7.8 #earthquake near Kamchatka have already rolled through #Victoria, BC (5131 km distant).
If you are looking for the latest #tsunami risk evaluation (and preparedness info) for the British Columbia coast, see
www.emergencyinfobc.gov.bc.ca/event/tsunam...
🌊⚒️🧪

Seismogram showing seismic waves from today's M7.8 Kamchatka earthquake that have rolled through Victoria, Canada (5131 km away and not felt here). Image thanks to IRIS/Earthscope.

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John Cassidy @earthquakeguy.bsky.social · 20d

Thanks, Jay!

John Cassidy @earthquakeguy.bsky.social · 20d

Did you feel shaking on southern #VancouverIsland at 5 a.m. today?
That was a M3.0 earthquake located 16 km SW of Duncan and 40 km WNW of #Victoria. Shaking was lightly felt across the region.
Details and report shaking:
www.earthquakescanada.nrcan.gc.ca/recent/2025/...
⚒️🧪

Seismograms showing ground shaking from the M 3.0 earthquake on southern Vancouver Island (40 km WNW of Victoria) at 5 a.m. PT, September 18.

Map showing the location of the M3.0 earthquake on southern Vancouver Island at 5 a.m. on September 18. The earthquake was located 40 km WNW of Victoria and 16 km SW of Duncan.

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John Cassidy @earthquakeguy.bsky.social · 22d

Thanks. Yes, you can always count on the west coast to provide those friendly little shaking reminders of an active earthquake zone. Only a few weeks now until the ShakeOut exercise!
California: www.shakeout.org/california/
British Columbia: www.shakeoutbc.ca

Earthquake Preparedness BC | The Great British Columbia ShakeOut

Sign Up for ShakeOut, an annual earthquake preparedness BC event, and practice how to be safer during earthquakes: Drop, Cover, and Hold On.

www.shakeoutbc.ca

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John Cassidy @earthquakeguy.bsky.social · 22d

Did you feel shaking on Haida Gwaii at 1:45 p.m. today (September 15)?
That was a M4.2 earthquake located off the west coast, 75 km west of Daajing Giids.
Details/report shaking: www.earthquakescanada.nrcan.gc.ca/recent/2025/...
This is not an unusual event for this region. No impacts expected. ⚒️🧪

Seismograms showing ground shaking from this afternoon's (1:45 p.m. PT 15 September) M4.2 earthquake located just to the west of Haida Gwaii (75 km west of Daajing Giids).

Map showing the location of today's (September 15) M4.2 earthquake located 75 km to the west of Daajing Giids.

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John Cassidy @earthquakeguy.bsky.social · 29d

Did you feel a slight shake east of Vancouver at 9:28 last night? That was a M2.6 earthquake located 33 km NW of Abbotsford and felt by many in the area.
earthquakescanada.nrcan.gc.ca/recent/2025/...
A reminder of an active earthquake zone, and to register for:
www.shakeoutbc.ca/join-the-dri...
⚒️🧪

Seismograms showing ground shaking from last night's M2.6 earthquake located 33 km northwest of Abbotsford.

Map showing the location of last night's felt M2.6 earthquake in southwest British Columbia. It was located 33 km northwest of Abbotsford.

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John Cassidy @earthquakeguy.bsky.social · Sep 7

At 8:00 a.m. PDT today, a M4.8 earthquake occurred in Canada's most seismically active region - offshore between #HaidaGwaii and #VancouverIsland. No damage or tsunami expected. ⚒️🧪🇨🇦
Details and to report felt shaking: www.earthquakescanada.nrcan.gc.ca/recent/2025/...

Map showing the location of the 7 September M4.8 earthquake located offshore between Haida Gwaii and Vancouver Island.

Seismograms showing ground shaking from this morning's M4.8 earthquake located offshore, about 75 km south of Haida Gwaii.

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John Cassidy @earthquakeguy.bsky.social · Sep 6

Yes, exactly! It was originally located in the pink Customs House building downtown on the waterfront. Now on display at the Pacific Geosciemce Centre, Geological Survey of Canada on Pat Bay.

John Cassidy @earthquakeguy.bsky.social · Sep 6

Thanks, yes, an interesting bit of Canadian history and an important step in earthquake science!

John Cassidy @earthquakeguy.bsky.social · Sep 6

High-tech in 1898!

John Cassidy @earthquakeguy.bsky.social · Sep 6

Yes - it works well! For the lemon tree (5-6 feet high) one string of 5W bulbs works. For the hummingbird feeder, I use a single 5W bulb if it goes below freezing. That works to about -5C / 23F. If it is colder than that you have to get more creative.

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John Cassidy @earthquakeguy.bsky.social · Sep 5

5 Sept. 1944: A damaging M5.8 #earthquake struck near Cornwall, #ON and Massena, #NY. Chimneys came crashing down and many masonry structures were damaged. Felt from Quebec City to New York to Toronto ⚒️🧪
www.earthquakescanada.nrcan.gc.ca/historic-his...
articles.adsabs.harvard.edu/pdf/1945JRAS...

Map showing the shaking intensity from the September 5, 1944 M5.8 earthquake near Cornwall, Ontario and Massena, New York. Ground shaking was felt from Quebec City to New York City and from Toronto to Boston.

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John Cassidy @earthquakeguy.bsky.social · Sep 4

Wow! 127 years of recording large, global #earthquakes in Victoria, Canada!
On September 3, 1898, a Milne seismograph began operation in the basement of the old Customs House building on the Victoria waterfront. It was one of the first seismographs in Canada:
science.gc.ca/site/science...
⚒️🧪🇨🇦

Photo showing the Milne seismograph that was first deployed in Victoria, Canada, in 1898.

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