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John Dehls

John Dehls

@john.dehls.net

940 followers 470 following 32 posts

Applying InSAR to landslides and other stuff at the Geological Survey of Norway (NGU). Opinions here are my own, not necessarily my employer's.

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John Dehls @john.dehls.net · Sep 22

I’d like to call your attention to a Special Session Drew Rotheram-Clarke (GSC) and I are co-chairing at #ISPRS2026 Toronto:
👉 “Cooperation on Ground Motion Monitoring for Disaster Risk Reduction and Resilience.”
👉 www.isprs2026toronto.com/special-sess...
#DRR #InSAR

ISPRS 2026 Special Sessions

Discover ISPRS 2026 Special Sessions – expert-led, in-depth discussions on emerging topics in photogrammetry, remote sensing, and spatial information sciences.

www.isprs2026toronto.com

Reposted by John Dehls

AnneliiD @anneliid.bsky.social · 8d

Full of leading scientific institutions, Trondheim could be a natural laboratory for world-class collective transport.
But progress remains constrained by car-centric policies that support electried, privately-owned cars. The thinking: Green cars = Green economic growth. A cosmetic solution.

John Dehls @john.dehls.net · 10d

On this International Day for Disaster Risk Reduction, iddrr.undrr.org, I'd like to call attention once again to our idea of an InSAR-based global ground motion service, and our upcoming special session at ISPRS in Toronto. Abstract deadline is Nov 3. www.isprs2026toronto.com/special-sess...

John Dehls @john.dehls.net · 17d

22:03 CET (10:03 PM)

Reposted by John Dehls

AnneliiD @anneliid.bsky.social · 24d

Consume less, live more.
#voluntarysimplicity
share.google/bAcEduwe30I6...

Forget materialism, a simple life is happier: research

In an age where billionaires and conspicuous consumption are increasingly on display, new Otago-led research shows a simple life really is a happier life.

John Dehls @john.dehls.net · 27d

Absolutely. Hydropower dams worldwide face similar risks—yet most have no satellite-based monitoring at all. Time to change that. Join us at #ISPRS2026 Toronto and help make the case for global ground motion services. bsky.app/profile/john...

John Dehls @john.dehls.net · Sep 22

If you’re working on ground motion, hazards, or resilience—we’d love your contribution. Join us in Toronto!
👉 www.isprs2026toronto.com/special-sess...

#InSAR #DisasterRiskReduction #ISPRS2026

ISPRS 2026 Special Sessions

Discover ISPRS 2026 Special Sessions – expert-led, in-depth discussions on emerging topics in photogrammetry, remote sensing, and spatial information sciences.

www.isprs2026toronto.com

John Dehls @john.dehls.net · 29d

We are very much looking forward to global L-band NISAR data! But this is definitely not new! We have been doing this for several decades.

John Dehls @john.dehls.net · Sep 22

We had tremendous response to our initiative for a Global Ground Motion Service at #GP2025 this spring.
The technology is proven. The data exists. Let's go global.
x.com/NorwayInGene...

John Dehls @john.dehls.net · Sep 22

From earlier this year at #GP2025: x.com/NorwayInGene...

John Dehls @john.dehls.net · Sep 22

If you’re working on ground motion, hazards, or resilience—we’d love your contribution. Join us in Toronto!
👉 www.isprs2026toronto.com/special-sess...

#InSAR #DisasterRiskReduction #ISPRS2026

ISPRS 2026 Special Sessions

Discover ISPRS 2026 Special Sessions – expert-led, in-depth discussions on emerging topics in photogrammetry, remote sensing, and spatial information sciences.

www.isprs2026toronto.com

John Dehls @john.dehls.net · Sep 22

That’s what our Special Session at #ISPRS2026 Toronto is about. Topics include:
· InSAR in DRR strategies
· Open services
· Multi-stakeholder cooperation
· Extending services to underserved regions

John Dehls @john.dehls.net · Sep 22

The tools exist to build a Global Ground Motion Service. Open #SAR missions like #Copernicus #Sentinel-1 and NASA/ISRO’s #NISAR can already track vast areas. What’s missing is cooperation.

John Dehls @john.dehls.net · Sep 22

Groundwater & infrastructure: Subsidence in California or Spain’s Guadalentín Valley shows how over-extraction damages farmland, cities, and flood defences. InSAR makes the invisible visible.

European Ground Motion Service map of the Guadalentín Valley, Spain. InSAR deformation points show a gradient from green (stable) to red (strong subsidence), revealing land sinking caused by intensive groundwater extraction in agricultural areas.

John Dehls @john.dehls.net · Sep 22

Mining & tailings dams: InSAR highlights deformation at sites like Uzbekistan. Failures can release toxins, devastate ecosystems, and take lives. Many risks are preventable if we act early.

Satellite image of a large tailings dam in Uzbekistan. InSAR deformation data shows a red band around the dam walls, indicating significant ground movement.

John Dehls @john.dehls.net · Sep 22

Glacial Lake Outburst Floods (GLOFs): InSAR detected precursory deformation at South Lhonak Lake before its catastrophic 2023 flood. These events cascade far downstream. (www.science.org/doi/10.1126/...)

Satellite view of South Lhonak Lake in the Himalayas, overlaid with InSAR deformation data. Red and orange zones along the moraine show precursory ground movement before the catastrophic 2023 glacial lake outburst flood.

John Dehls @john.dehls.net · Sep 22

Here are three examples from San Juan Province, Argentina, highlighted by #InSAR. These slow-moving landslides affect large, high-relief mountain slopes and demonstrate the value of regional-scale monitoring for identifying potential geohazards in remote areas where on-the-ground access is limited.

Satellite images of steep mountain slopes in Argentina. Top row shows natural-colour terrain. Bottom row overlays InSAR ground deformation data, with red areas marking active slope movement, highlighting large, slow-moving landslides across the region.

John Dehls @john.dehls.net · Sep 22

But what about the rest of the world? Most regions still don’t have access to this kind of critical information. Too often, where hazards are highest, monitoring is weakest. That gap must close.

John Dehls @john.dehls.net · Sep 22

#InSAR is a proven technology for disaster risk reduction—and it scales. Examples like InSAR Norway insar.ngu.no and the European Ground Motion Service already provide billions of open measurements.

Image from InSAR Norway showing a fjord with mountainsides. The mountainsides are coloured red where unstable slopes are moving.

John Dehls @john.dehls.net · Sep 22

Why are we organizing this? To push forward a new initiative: making life-saving ground motion data available worldwide, especially where it’s needed most.

Partial globe showing coverage by the European Ground Motion Service, showing dense deformation measurements. Highlights how some regions have access to life-saving data, while most of the world does not.

John Dehls @john.dehls.net · Sep 22

I’d like to call your attention to a Special Session Drew Rotheram-Clarke (GSC) and I are co-chairing at #ISPRS2026 Toronto:
👉 “Cooperation on Ground Motion Monitoring for Disaster Risk Reduction and Resilience.”
👉 www.isprs2026toronto.com/special-sess...
#DRR #InSAR

ISPRS 2026 Special Sessions

Discover ISPRS 2026 Special Sessions – expert-led, in-depth discussions on emerging topics in photogrammetry, remote sensing, and spatial information sciences.

www.isprs2026toronto.com

John Dehls @john.dehls.net · Aug 16

Fantastic!

John Dehls @john.dehls.net · Jul 30

Figure taken from www.isro.gov.in/media_isro/p...

www.isro.gov.in

John Dehls @john.dehls.net · Jul 30

I guess I will be holding my breath until about 14:29 CET today. #NISAR #InSAR

NISAR launch schedule, Launch at 14:10 CET, separation at 14:28.

John Dehls @john.dehls.net · May 22

And in related weird news, a quick clay slide was triggered near Trondheim, Norway, when a container ship ran aground next to a house! www.nrk.no/trondelag/hu...

Hus evakueres etter leirras like ved containerskip på Byneset i Trondheim

Like ved stedet lasteskipet traff land har det gått et 100 meter bredt leirskred.

John Dehls @john.dehls.net · Apr 28

CLICKBAIT VOICE
We processed radar images...
You won't believe how much the ground moved!

HAIKU VOICE
Silent satellites.
Unwrapped phase reveals secrets.
The land shifts unseen.

CONSPIRACY VOICE
Supposed "scientists" claim ground deformation,
based on "interferograms" from secret radar images.

Tom Gauld @tomgauld.bsky.social · Apr 28

My latest @newscientist.com cartoon

Title:
SOME GRAMMATICAL VOICES FOR USE IN SCIENTIFIC WRITING

ACTIVE VOICE
e.g.
Our team collected samples and then we tested them.

CLICKBAIT VOICE
e.g.
We collected some samples...
You won't believe what happened next!

PASSIVE VOICE
e.g.
Samples were collected and tested.

HAIKU VOICE
e.g.
Quiet science lab.
Workers arrive with samples.
The testing begins.

PASSIVE-AGGRESSIVE VOICE
e.g. We did all the collecting and testing.
No need to thank us.
Just doing our job.

CONSPIRACY VOICE
e.g.
Mysterious "Samples" were harvested and covertly "tested" by so-called scientists.

John Dehls @john.dehls.net · Apr 19

A proper tiramisu always starts with making a zabaglioni, to get a nice thick texture. I think the pasteurization is a secondary effect.