Lightnews — Scholar-powered news

Claudio Satriano

@claudio.seismicsource.org

120 followers 75 following 9 posts

Seismologist, Continuous learner

https://github.com/claudiodsf
https://seismicsource.org

Posts Replies Media Videos

Reposted by Claudio Satriano

Simeon Schmauß

@stim3on.bsky.social

I also derived a new elevation model from the aerial images, allowing me to visualize the elevation change in the affected areas.
The rocks and debris in the valley are locally up to 32m thick and I estimate the total displaced volume is about 11 million cubic meters. #Blatten

Map of the Lötschtal showing the area affected by the glacier collapse.
Blue colors show lost elevation, red areas elevation gains.
The two most notable areas are the collapsed peak of Kleines Nesthorn and the collapsed glacier which are shown in deep blue with elevation loss of up to 128m and 51m respectively.
The material slid down the mountain in an approximately 400m wide path and accumulated in a 2,5km long area on the valley floor which is up to 32m thick.
The newly formed lake above the village of Blatten is also drawn in.

The Map text reads:
Kleines Nesthorn and Birchgletscher collapse / Blatten im Lötschental (VS)
On Wednesday, May 28th, a2025, the Birchgletscher glacier collapsed under the weight of rock and debris following the partial collapse of the Kleines Nesthorn.
Approximately 10 million cubic meters of debris flowed into the valley, burying large parts of the villages of Blatten and Ried. The debris also blocked the Lonza River, forming a small lake that destroyed several more houses in Blatten.
Analyis
Using Oblique imagery collected and provided by swisstopo on May 30th, 2025, a photogrammetric DEM was created and compared to the swissALTI3D DEM.

The following volume change was measured in the affected area:
Above Volume (m³): 11.2 Mio
Below Volume (m³): 10.1 Mio

June 1, 2025 at 9:39 AM

Claudio Satriano

@claudio.seismicsource.org

My automated inversion of source spectrum captured the largest one (Mw 3.3), with an interesting peak at 10 Hz at all the recording stations 🤔. More details: ssphex.ipgp.fr/catalog/fr20.... The SspHex website: ssphex.ipgp.fr

June 1, 2025 at 9:22 AM

Reposted by Claudio Satriano

Tom Gabrieli

@tgabrieli.bsky.social

Very (very) rough analysis indicates >6 m of slip.
I resolve pixel offset using DIC in experimental cm sized samples with speckle pattern, and never used it before on satellite images. However the dextral offset is pretty clear, and I trust my calibration so the slip magnitude should be about right.