Tim Demko

@timdemko

Geologist interested in the energy transition, bicycling, and public service

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Tim Demko@timdemko· 11d

Same event on my RaspberryShake 4D seismometer in Lexington, Kentucky USA

Screenshot of ShakeNet app showing seismograph of magnitude 7.4 earthquake in Columbia on August 10, 2026, as recorded by a RaspberryShake 4D seismometer in Lexington, Kentucky USA.

Tim Demko@timdemko· 15d

I used these outcrops for the classes I taught at University of Minnesota Duluth. There is actually quite a long section exposed downstream of the dam. Yes there is foliation, but bed boundaries are still discernible, as well as enough sed structures to determine way-up.

Photos of students measuring stratigraphic sections in a river gorge.

Tim Demko@timdemko· Jun 9

Big Irwin Mainway vibes

Dan Ackroyd and Candice Bergen in the Saturday Night Live Sketch about a sleazy toy manufacturer, Irwin Mainway (Ackroyd), who sells extremely dangerous toys. Ackroyd is holding a plastic bag of broken glass, the "Bag O' Glass" toy.

Dan Ackroyd in a Saturday Night Live Sketch about a sleazy toy manufacturer, Irwin Mainway (Ackroyd), who sells extremely dangerous toys. Ackroyd is holding a bag containing a plastic dry cleaning bag, the "Johnny Space Commander" toy.

Tim Demko@timdemko· May 30

Here are responses from nearby Raspberry Shake seismometers, on the left a RS 4D in Titusville, FL 34 km to the NW, and on the right a RS 3D between Vienna and Melbourne, FL 38 km to the SW of the event. The 4D picked up higher frequency vibrations (peak ~6Hz) while the 3D recorded lower (~0.85 Hz).

Illustration of seismic response of the Blue Origin New Glenn rocket test failure. The figure has three sections: the time-series waveforms, a spectrogram of the frequencies, and a power spectrum.

Map of the Florida coast, showing positions of the Blue Origin New Glenn rocket test failure and explosion, and two Raspberry Shake seismometers that recorded vibrations from the event.

Tim Demko@timdemko· May 9

Best film adaptation of The Odyssey, wrong answers only

Movie poster for the 1985 Martin Scorsese film "After Hours". The poster depicts the lead actor, Griffin Dunne, running through a geometrically-confusing urban scene. Dunne is wearing a light colored blazer and pants, a dark striped shirt, and brown shoes.

Tim Demko@timdemko· Apr 11

Astronaut Leland Melvin FTW www.reddit.com/r/space/s/Dn...

Official NASA portrait of astronaut Leland Melvin and his dogs.

Tim Demko@timdemko· Mar 3

I've started my new job as a geologist with the Kentucky Geological Survey. There are exhibits of two types of fossil trees in and around the KGS building: a cast of a Carboniferous lycopod (my MS thesis) and petrified wood from the Triassic Chinle Formation (my PhD). The universe is a closed loop.

Photo of the entrance to the Mining and Mineral Resources Building on the University of Kentucky campus, the home of the Kentucky Geological Survey.

Photos of the geologic map of the State of Kentucky.

Text on the map reads: Celebrating Geologic Mapping in Kentucky, first in the United States: topographic maps (1:24000 scale), geologic maps (1:24000 scale), digital geology, web accessibility

Photo of a fossil casted tree stump and attached rooting structures. This Carboniferous-age tree was a club moss (lycopod), and the rooting structures are called Stigmaria.

Photo of a polished slab of colorful petrified wood. Tree rings are visible in the red, gray, and black mineralized wood.

Tim Demko@timdemko· Jan 27

You could also make the Grand Tour, visiting the Salton Sea Mud Volcanos and visit the tourist haunts of the Republic of Slowjamistan. Don't forget the guacamole recipe! vimeo.com/128414770?fl...

Photo of a woman and man standing in front of a sign which read "Republic of Slowjamistan www.slowjamistan.org". It is in a stark desert landscape, with a blue sky and wispy cirrus clouds/

Tim Demko@timdemko· Jan 18

Same energy

Tim Demko@timdemko· Jan 17

Destiny is all!

Photo of the three main warriors from the TV series "The Last Kingdom", Uthred, Finn, and Sitric.

Tim Demko@timdemko· Jan 8

I rarely post photos of myself, especially in uniform, but the events of today are clashing mightily with the stupendous day I had in the field yesterday. Here I am, mid geologizing mode, waxing eloquently about some fascinating details of the 1.7 byo schist in the background. Must remember...

A photo of a geologist standing on an outcrop, pointing to a cliff face in the background. He is holding a map board, there are trees, and clouds in a brilliant Arizona blue sky. It was a good. No, great.

Tim Demko@timdemko· Jan 2

Here is the response from the earthquake near Acapulco, Mexico on my RaspberryShake 4D seismometer near Phoenix, Arizona USA, 2252 km from the event.

Illustration showing seismometer response to a magnitude 6.5 earthquake which occurred near Acapulco, Mexico on January 2 at 13:58:18 UTC. There is a map on the left which shows the location of the earthquake, connected with a great circle path to the location of the seismometer near Phoenix, Arizona USA. There are time-series plots of the seismic waveform and frequency on the right.

Tim Demko@timdemko· Jan 2

Well, this should be a very interesting year...I think

Tim Demko@timdemko· Dec 31

Same event on my RaspberryShake 4D near Phoenix, Arizona USA, 8,774 km away.

Illustration showing a seismometer response near Phoenix, Arizona USA to an earthquake near Honshu, Japan. On the left, there is a map showing the location of the earthquake and a great circle line to the location of the seismometer. On the right are time-series plots of the waveform (a line showing the amplitude expressed as vertical velocity in microns/second) and frequency (graphically expressed in a color representation in Hertz).

Tim Demko@timdemko· Dec 20

"Ghost Ranch block" (Triassic Chinle Formation), preserving numerous Coelophysis dinosaurs and other reptiles. This block is in collections of the Museum of Northern Arizona in Flagstaff, AZ USA. 16 of these blocks were distributed from New Mexico to museums and schools in the 1980s. #fossilfriday

Photo of a block of Upper Triassic Chinle Formation from Ghost Ranch, New Mexico USA that preserves numerous Coelophysis dinosaurs and other small reptiles. There is a life-size drawing of a Coelophysis dinosaur behind the block of rock. The block is in the crowded collections room back-stage in a museum.

Close-up photo of a block of Upper Triassic Chinle Formation from Ghost Ranch, New Mexico USA that preserves numerous Coelophysis dinosaurs and other small reptiles. There are numerous small bones of a crocodylomorph reptile exposed in a block of light reddish brown siltstone. There is a sign on the block that says "Please do not touch!".

Tim Demko@timdemko· Dec 18

The tracks were so fresh-looking, we could almost smell the critters!

Photo of a rock with the cast of a reptile footprint. There is a pen for scale.

Tim Demko@timdemko· Dec 18

Spectacular scenery, weather, and colleagues! And the tracks and traces weren't bad either!

Photo of a group of people near a white pickup truck. They are in a rocky desert setting, with snow-capped peaks in the distance.

Photo of a rock slab, the base of a sandstone block with numerous tracks, trails, and other trace fossils. There is a boot for scale.

Tim Demko@timdemko· Dec 10

We spent 10 days beach camping in northern Baja, going out every low tide to spy G. palmeri colonies, looking for the slit-like burrows, measuring individual burrow widths, excavating the makers and measuring their shell widths. Ended up with 75 individual measurements.(3/3) doi.org/10.1111/j.15...

Comparison of size-structure in two populations of Glottidia
palmeri from tidal flats of northeastern Baja California. Black bars
denote the population from Campo Don Abel and dotted bars the population from Vega Island. Comparison of size-structure of two populations as revealed by width of shells collected alive. UB. Comparison of the same two populations with use of burrow width.

Comparison of burrow and shell width in two populations of
Glottidia palmeri, northeastern Baja California, Mexico.

Tim Demko@timdemko· Nov 14

For me, it was just looking at the title of this book in a university bookstore, probably sometime Spring semester 1991. I picked it up, turned right to font section, and within minutes, the lightbulb popped up above my head. Never looked back!

Image of the cover of the book "The Mac is not a typewriter". On the cover is an image of an old Corona typewriter.

Tim Demko@timdemko· Oct 6

After liking this post and reading the linked paper, I was keen to see if I'm missing these features in outcrops. Tooling around some basalt flows along Kona Coast in Hawaii today (Shoreline Park, just west of Kealakekua)...well, yep! Will be keeping my eye peeled for these in older flows in AZ!

$Photo of the an outcrop of dark gray vesicular basalt, exhibiting fracture patterns of two natural explosion structures. The structures look like cavities surrounded by radially-oriented fractures. My sandaled foot is also shown, for scale.$

Tim Demko@timdemko· Oct 3

Any self-respecting ichnologist despises fish because they can make the most frustratingly uninterpretable traces. www.livescience.com/63627-puffer...

Photo of a Japanese pufferfish posing defiantly in front of its needlessly complicated and beautiful sea floor sand sculpture. Asshole!

Tim Demko@timdemko· Sep 13

Here is the response from the event on my RaspberryShake 4D seismometer near Phoenix, AZ USA

Seismogram of 7.4 magnitude earthquake off Kamchatka as measured on a RaspberryShake 4D seismometer near Phoenix, AZ USA. The figure is a composite diagram with 3 parts: an upper record of the seismic wave amplitude over time, a middle part showing the frequency spectrum over time, and a lower graph of the complete frequency spectrum over the time interval of the upper two parts

Tim Demko@timdemko· Sep 9

After poking around and finding the base of the flow, the story became much richer: the basalt had flowed over some eolian dunes which sourced the water for the hydrothermal system. The sand might have accumulated as obstacle dunes around a bedrock hill, then buried by the flow in a valley. (2/2)

$Outcrop photo of Miocene eolian dune deposits overlain by vesicular basalt. The dune deposits are light orange-brown and characterized by wind ripple/translatent (pin-stripe) laminations, and the basalt is very dark reddish brown. The basalt exhibits intense fracturing, with light colored fracture fills. the contact is very sharp. There is an archaeologist (Madi Whalen) for scale.$

$Outcrop photo of Miocene eolian dune deposits overlain by vesicular basalt. The dune deposits are light orange-brown and characterized by wind ripple/translatent (pin-stripe) laminations, and the basalt is very dark reddish brown. The basalt exhibits intense fracturing, with light colored fracture fills. There is an archaeologist (Madi Whalen) for scale.$

$Outcrop photo of Miocene eolian dune deposits overlain by vesicular basalt. The dune deposits are light orange-brown and characterized by wind ripple/translatent (pin-stripe) laminations, and the basalt is very dark reddish brown. The basalt exhibits intense fracturing, especially at the contact with the underlying sandstone, with light colored fracture fills. The units and the contact are offset by a small vertical fault.$

Tim Demko@timdemko· Sep 9

Saw these outcrops of the mineralized, brecciated top of a Miocene basalt flow today, evidence of an epithermal hydrothermal system. This indicates the interactions of mineralized, boiling water, explosively flashing to steam, breaking up the rock, depositing minerals in fractures and cavities (1/2)

$Outcrop photo of brecciated basalt, with dark pieces of vesicular basalt separated by lighter interstices, fracture fills, and mineralized cavities. The photo is of a vertical profile of the top of a basalt flow. There is a cell phpne for scale.$

$Outcrop photo of brecciated basalt, with dark pieces of vesicular basalt separated by lighter interstices, fracture fills, and mineralized cavities. The photo is looking down onto the top of a basalt flow. There is a boot for scale.$

Tim Demko@timdemko· Aug 25

Joe's post reminded me of this piece of artwork given to me me by the artist, William "Rockman" Gooder from Duluth, MN. William would come to my office with collections of stones he chose from the gravel beaches of Lake Superior for his artwork, asking me to to tell him the story of each one. (1/2)

Framed artwork made of multicolored rocks and tan sand from the shores of Lake Superior, MN. Artwork by William Gooder: https://www.williamgooder.com/

Tim Demko@timdemko· Jul 30

MEGAQUAKE! 8.7 off of Kamchatka. Here is the response on my RaspberryShake 4D in Phoenix, AZ USA #earthquake #RaspberryShake

Seismograph showing response from a magnitude 8.7 mega earthquake off of the southern Kamchatka peninsulaon a RaspberryShake 4D seismometer in Phoenix, AZ USA. The figure has three graphical sections: 1) a time series of the amplitude of vibrations in meters/second over about 50 minutes, 2) a time series of the frequency response over the same time interval, and 3) an amplitude versus frequency diagram showing a peak frequency of about 0.25 Hertz

Tim Demko@timdemko· Jul 20

Cover of DC Comics Unexpected #157, showing panels from stories "Who Will Kill Gigantus" with a theropod dinosaur chewing a battle tank on the steps of the Capitol, "The Abominable Snowman" with a giant yeti about to throw an enormous snowball at someone viewing it's tracks, and "The Thing from the Dead Letter Office" with a monster peaking into a window in a room with a cowering woman.

Tim Demko@timdemko· Jun 15

Here are some highlights from deep red Surprise, Arizona. There were several hundred folks lining about 4 blocks, both sides of the highway. Well behaved, except for a few drive-by hecklers. The group was very diverse, happy, and fired up! Kudos to the No Kings organizers!

Protest sign that reads "Gestapo 1933, ICE 2025"

Protest in Suprise, AZ; people holding protest signs: "Nobody is illegal on stolen land", "rebellion against tyrants is obedience to God - Benjamin Franklin", "Respect the Constitution, uphold the rule of law", "One wing for justice, one wing for judgement"

Protest sign: "Does this ass (photo of Trump) make my country look small?"

Protest sign: painting of the Statue of Liberty covering her eyes

Tim Demko@timdemko· May 15

Thought of this photo right away: left it all in the field! Clockwise from left: Brian Bodenbender, me, Mark Uhen: Shell, WY, July 2004. We survived.

Three dirty, exhausted, and happy geologists, sleeping sacked out in camp chairs and on the ground.

Tim Demko@timdemko· May 6

Artificial Intelligence when I was a kid: