Luca Malatesta
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geoluca.bsky.social
Luca Malatesta
@geoluca.bsky.social
1.3K followers 600 following 290 posts
Geologist at GFZ (gfz.bsky.social). Interested in all things tectonic and climatic geomorphology.
https://www.gfz-potsdam.de/en/staff/luca.malatesta/sec47
ORCID https://orcid.org/0000-0003-0983-715X
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geoluca.bsky.social
It makes a whole lot of sense yes, the coastal slope hosting the initial road is very landslide prone. (Actually the initial road has been wiped down). Google map has been updated, but the satellite images are still pre-EQ. Free flat land!
November 14, 2025 at 10:10 PM
geoluca.bsky.social
On Noto Peninsula where coseismic uplift was ~2m.
Sequence pre-earthquake, EQ +3 months, EQ +23 months. I thought we would be able to monitor this nice flat surface for weathering efficiency over the years…
Noto coast in Nov. 2023. Waves come all the way up to a concrete embankment protecting a cliff Noto Coast after 2 m coseismic uplift. 100 m wide rock platform is now emerged A road is now built on the bedrock platform, protected by a new sea wall
November 14, 2025 at 9:43 PM
geoluca.bsky.social
🙌🏻
November 7, 2025 at 8:42 AM
geoluca.bsky.social
Ha! What a neat little app. Makes you pay attention to relative speeds around you
Train tracks and train In front of a building. Moving Train is rendered in three successive shots in R G and B.
October 10, 2025 at 11:50 AM
geoluca.bsky.social
We'll try a 360º camera to document field sites google-streetview-style and to plunge it under our kayak looking for faults. In the meantime, enjoy this gimmicky autumnal snapshot @gfz.bsky.social .
October 7, 2025 at 10:32 AM
geoluca.bsky.social
We had the chance to do just that a month or so ago! We could play around with quick sand until someone starts to sink. (We got them back)
June 25, 2025 at 6:51 PM
geoluca.bsky.social
Just off the @weareseismica.bsky.social press: Annabel Händel & Co. on IDing seasonal variations in seismic site responses across Japan 🫨vs🌡️❄️🌧️. Very grateful to have been invited to join this puzzling investigation.
And lots of work remain!
doi.org/10.26443/sei...
(a) Location of the 188 KiK-net sites analyzed in this study (gray triangles) and the 13 sites with pronounced seasonal variation in ∆κ0 (highlighted triangles). The different colors indicate clusters of sites that respond differently to environmental change. (b) Zoom on the northeast corner of Hokkaido and (c) Honshu. The crosses indicate the locations of JMA weather stations. Stack of all 4626 ∆κ0 values observed in the pe- riod 2004–2020 in one year for the Honshu site cluster (blue triangles in Fig. 1). Gray dots: Mean ∆κ0 values for each day of the year and for each of the Honshu sites. Black curve: Mean curve computed from all gray dots, smoothed with a Gaussian filter of 6 days width. Red: Daily mean tempera- ture stacked to one year (red bars) and smoothed a Gaus- sian filter of 6 days width (red curve). Stack of all 1331 ∆κ0 values observed in the pe- riod 2004–2020 into one year for the Hokkaido site cluster (red triangles in Fig. 1). The data is plotted from July to July to have the winter month in the middle. Gray dots: Mean ∆κ0 values for each day of the year and for each of the Hokkaido sites. Black curve: Mean curve computed from all gray dots, smoothed with a Gaussian filter of 6 days width. (a) Orange: Daily minimum temperature stacked to one year (bars) and smoothed with the same Gaussian filter (orange curve). Red: Same for the daily maximum temperature. The orange and red dashed lines mark the times where the mini- mum and maximum daily temperatures start to be below or above 0°C. (b) Blue: Total daily precipitation stacked to one year (bars) and smoothed using a Gaussian filter of 6 days width (blue curve). Green: Average depth of snow cover. Stack of all 145 ∆κ0 values observed in the period 2009–2014 at YMTH07 (green triangle in Fig. 1) into one year. Gray dots: Mean ∆κ0 values for each day of the year. Black curve: Mean curve computed from all gray dots, smoothed with a Gaussian filter of 6 days width. (a) Blue curve: Total daily precipitation stacked to one year (bars) and smoothed with the same Gaussian filter (blue curve). Green: Average depth of snow cover. (b) Olive curve: Same as for (a) but for daily soil moisture content.
June 17, 2025 at 8:23 AM
geoluca.bsky.social
We are looking for a postdoctoral researcher to study submarine faults "just offshore". The postdoc will participate in all steps of the research from the development of an autonomous kayak w/ sonar to the analysis of bathymetric data for active tectonics. 📆 22 June!
www.gfz.de/en/career/jo...
Eastern Adriatic coast, with an outline of the large shallow water domain. a map of Cephalonia showing active faults at shallow water depths The kayak in the process of outfitting for autonomous surveys.
June 17, 2025 at 8:02 AM
geoluca.bsky.social
Distribution of permafrost around and above the Birch glacier assembled with swisstopo's online tools. Satellite image from May 30th.
s.geo.admin.ch/5yidukhr2udy

And go check @stim3on.bsky.social 's great work to explore the geometry of this permafrost area in 3d!
Satellite image of the Blatten collapse with permafrost extent as overlay. The unstable north-facing slopes of the Kleines Nesthorn that collapsed on the Birch glacier are mapped as "extensive permafrost"
June 2, 2025 at 9:19 AM
geoluca.bsky.social
In Gampel & Steg, bridges are closed/removed and excavators are deployed preventively in town & in Rhone to remove sediment that could block the water.
Today 22ºC, rain on Mon–Wed (16–18ºC) but not expected to cause significant problems.

(source: Pomona and SRF)
pomona.ch
www.srf.ch/news
4/4
an excavator at the confluence of the Lonza and the Rhone. Source: Pomona Media. the Lonza River flows across an alluvial fan on which the towns of Gampel and Steg are built. Source Swisstopo
June 1, 2025 at 10:09 AM
geoluca.bsky.social
Sediment-laden water flows downvalley to the Fersen hydroelectric dam; kept at a low level to catch any large debris flow. Turbines are off and water passes through a sluice. Before reaching the Rhone river, the Lonza passes through the town of Gampel & Steg.

(source: Pomona and SRF)
2/4
Fersen dammed lake kept at a low level. Source SRF/ Sandra Brand
June 1, 2025 at 10:09 AM
geoluca.bsky.social
In Lötschental: the Kleines Nesthorn remains unstable, rocks pile up on what remains of the Birchgletscher-> risk of further rock-ice avalanches. The Lonza flows across the entire deposit, dammed lake is monitored and stable. Deposit too weak for machinery.
(source: Pomona and SRF, 📷 A. Amherd)
1/4
June 1, 2025 at 10:09 AM
geoluca.bsky.social
It is not emptying afaik,but there is enough outflow to match the incoming river discharge. The lake did drop a little overnight according to the latest press conference. That would match the effect of the lower incoming discharge at night. (Light blue curve below)
May 30, 2025 at 5:51 PM
geoluca.bsky.social
The energy release in such collapse events is indeed significant. It played a role in the Piz Cengalo-Bondo rockfall-debris flow of 2017. Below a screenshot of an article by Martin Mergili et al. (🔗 below) discussing the water provenance.

nhess.copernicus.org/articles/20/...
There is still disagreement on the origin of the water that led to the debris flow, particularly to the first surge. Bonanomi and Keiser (2017) clearly mention meltwater from the entrained glacier ice as the main source, whereby much of the melting is assigned to impact, shearing, and frictional heating directly at or after impact, as is often the situation in rock-ice avalanches (Pudasaini and Krautblatter, 2014). WSL (2017) has shown, however, that the energy released was only sufficient to melt approximately half of the glacier ice. Water pockets in the glacier or a stationary water source along the path might have played an important role (Demmel, 2019). Walter et al. (2020) claim that much of the glacier ice was crushed, ejected, and dispersed (Fig. 30), whereas water injected into the rock avalanche due to pore pressure rise in the basal sediments would have played a major role. In any case, the development of a debris flow from a landslide mass with an overall solid fraction of as high as ~0.85 (considering the water equivalent of the glacier ice) requires some spatio-temporal differentiation of the water and ice content. We consider two qualitative conceptual models - or scenarios - possibly explaining such a differentiation:
May 30, 2025 at 10:22 AM
geoluca.bsky.social
2/2 I don't know how much of the water mentioned by Mayoraz is 1) melting of the deposit's ice (massively heated by the collapse itself), or 2) the Lonza seeping through. I'd imagine mostly the former given how muddy (low permeability) the dam is. Below a screenshot from SRF (📷 Thursday)
A helicopter view looking downvalley across the debris deposit. Small lakes and surface drainage are visible on the surface.
May 30, 2025 at 9:57 AM
geoluca.bsky.social
Glacier did not look happy about the whole situation even before the mountain fell on its face.
May 29, 2025 at 10:17 PM
geoluca.bsky.social
Situation this morning, credit zvg/canton Wallis via Pomona media. The water now sadly covers many of the houses that were spared by the collapse.
A lake dammed by the debris from the collapse of the Birch glacier covering Blatten.
May 29, 2025 at 11:18 AM
geoluca.bsky.social
I think that the settlement above the deposit is Weissenried, nearly 250 m above the valley floor! (likely built on top of a lateral moraine, hence the straight slope). Terrifying event.

s.geo.admin.ch/xky6k9n1cnfy
May 29, 2025 at 6:45 AM
geoluca.bsky.social
Helicopter view published by Pomona Media (🔗 below) shows the lake building up by the end of the day. 5 m3/s is a lot of water.
youtu.be/R0YlCNDW2l4?...
May 28, 2025 at 8:30 PM
geoluca.bsky.social
Looking at the various angles provided by SRF and Pomona, that is the extent of the debris cover I could follow. Leading to >130 buried structures, that includes smaller sheds.
NOT VERIFIED AGAINST COMPLETE AERIAL IMAGERY.
satellite image with a polygon showing the extent of the glacier collapse over the village of Blatten.
May 28, 2025 at 4:58 PM
geoluca.bsky.social
The Lonza River was gauged in Blatten. It was flowing at around 5 m3/s over the last weeks. Historically that would double for the month of June according to the last 30 yrs of record.
www.hydrodaten.admin.ch/en/seen-und-...
May 28, 2025 at 4:43 PM
geoluca.bsky.social
Maybe >~100 🏠 buried by the glacier+rockfall collapse in Blatten (polygon quickly drawn from 📷 pomona.ch). Upstream part of village spared. But the Lonza River is now dammed. Over the last month it flew at ~5m3/s, expected to increase 2-3x in June. At 10 m3/s, it's 1M m3 every 28 hours.
NOT VERIFIED, an approximate polygon drawn from media images shows the extent of the Birch glacier collapse above Blatten. The location of the Lonza River gauge station in Blatten (now out of order) last 40 days of the Lonza River discharge at Blatten, light blue, about 5m3/s on average Average flow of the Lonza River at Blatten over the last 30 years. It shows a significant increase from May (average 5.7 m3/s) to June (average 11 m3/s)
May 28, 2025 at 4:39 PM
geoluca.bsky.social
Dimitri Lague guides us through the labs of OSERen at the University of Rennes, here an experiment by Laure Guérit.
Fantastic collection of nimble experiments run by geologists, ecologists, physicists, hydrologists and others. Smart resource sharing
A 3D printed catchment to study sediment transport
May 21, 2025 at 9:37 AM
geoluca.bsky.social
Main takeaway from visiting the Mont St Michel: the next Zelda should be in a mega-tidal environment.
A view of the mt st Michel with the sun behind
May 20, 2025 at 5:53 PM
geoluca.bsky.social
Here's a before-after with a fixed foreground. Hard to make a perfect job with the shaking but it might help to identify changes by flipping back and forth.
May 13, 2025 at 11:33 AM