Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026We estimate that the event accommodated 2-4 m of plate separation, of which ~10% corresponded to slip on axis-bounding faults. 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026We later modeled the horizontal and vertical displacements that had been measured by the geodetic array. While many models can fit the data, all of them point to substantial drainage of a magma pocket several km deep, meter-scale opening of a dike, and slip on adjacent faults. 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026By comparing the bathymetric map we acquired in 2025 vs. the one from 2024, we calculated that ~160 million cubic meters of lava had poured out onto the seafloor. That’s over 60,000 olympic pools worth of lava! 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026Lava effusion continued for several weeks, with a few bursts of activity. When we returned to the site in early 2025, we were shocked to find that up to 100 m thick lava flows had been emplaced along the axis. 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026The temperature of the deep ocean also rose by a fraction of a degree, a clear sign that hot stuff was flowing out of the seafloor! 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026Seafloor subsidence continued for a few days, reaching a total of 4.2 meters. Meanwhile, our hydrophone network started picking up "impulsive" sounds characteristic of lava encountering water. 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026At the same time, our acoustic beacon array measured over 1 m of extension between the middle of the axial valley and the first abyssal hill to the SW: a combination of dike-accommodated stretching and normal fault slip. 111
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026The swarm migrated to the SE, and was quickly followed by a second one, which migrated to the NW at ~2 m/s, along the ridge axis. This is a typical signature of magma-filled fractures (dikes) propagating from a magmatic segment center. 121
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026On April 26, 2024 at about 8 pm UTC, a big swarm of (mag~5) normal faulting earthquakes started in the middle of segment I1, at 37°S on the Southeast Indian Ridge… just below our geodetic network! 121
Reposted by benoit ildefonseThe OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · 08/07/2026The news is out today in @nature.com ! The OHA-GEODAMS observatory had the incredible luck to capture a major seafloor spreading event back in 2024, just 2 months after its deployment. You can read all about it at: www.nature.com/articles/s41... Here’s how it unfolded 👇nature.comAnatomy of a seafloor spreading event captured by in situ seismogeodesy - NatureBy combining hydroacoustic, direct-path ranging and bottom-pressure measurements, in situ observations of a rifting event at a segment of the Southeast Indian Ridge are reported, providing insight int... 21311
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 02/07/2026The #NODSSUM docked @ Brest Sun 28th. Exciting science: 19 Nautile dives to 4700 m, more than 100 barrels imaged, sediment, biota & water filter, coring, fish traps... peek to photos & videos for a week here: www.swisstransfer.com/d/22d399c8-a... From tomorrow here: sdrive.cnrs.fr/s/t7jH3ofqfk... 24416
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 26/06/2026And after a night camera tow photographing the seafloor, a last, short Nautile dive for the #NODSSUM cruise - over a whale fall and its ecosystem and final inspection of radioactive waste barrels. Now en route to Brest: writing, packing, back ups of data, cleaning labs… ETA Sunday afternoon 0104
Reposted by benoit ildefonseGDR-SciNEE @scinee.bsky.social · 22/06/2026Thanks to the use of the submersible Nautile, the #NODSSUM campaign have been able to collect samples from the barrels as well as seawater, sediment and marine organisms. At each return of Nautile from a dive, radiation levels on the sub and in the samples are controlled by the radioprotection team. 095
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 21/06/2026Rainy day start - with preps for the #NODSSUM cruise dive 2194, 16th of this cruise: launch the elevator to 4700 m with corers for Nautile, checks on the sub, prep of the basket… and the tool shack. 074
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 21/06/2026And during #NODSSUM, to gather additionnal images from biota, ecosystems, and dumped radioactive waste barrels, the deep-sea camera system SCAMPI, that flies two to three meters above the seafloor, taking snaps every 10 seconds, over several km, towed behind the ship. 064
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 21/06/2026Sediments provide a good environmental record of both natural and artificial radionuclides. To sample them, #NODSSUM deploys from the ship a coring system with multiple tubes, that preserves the interface between water and sediment, critical to our studies. 7 coring sites to date, more to come. 043
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 10/06/2026The #NODSSUM cruise reaches cruise speed. Three Nautile dives have recovered sediment, biologic specimens, water, and video of dumped barrels and ecosystems- plus towed camera runs and fish traps (2 abyssal grenadines to date) - with fair weather ahead after a stormy start. 0144
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 05/06/2026#NODSSUM Pourquoi Pas? is in stand by - waiting on weather (WOW), with a depression passing over us. Sunday we plan our first Nautile dive after 1 week of unfriendly seas, and operations will start rolling. 1st dive over one of the selected radioactive waste barrel sites 1116
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 25/05/2026#NODDSUM the new home till the end of June - Le Pourquoi Pas? de la flotteoceanographique.fr, w/ Nautile submarine onboard. The team converges to Brest this Monday w/ more material & instruments. Tomorrow boarding & lab set-up, departure Wed 27th 1st thing in the morning. 093
Reposted by benoit ildefonseJavier Escartín @jescartin.bsky.social · 19/05/2026#NODSSUM a week away from departure for 2nd NODSSUM cruise @ NE Atlantic nuclear waste dump site we visited last year. Last-minute prep w/ transport of cruise material towards Brest - Including an important box just received. W/ the French Oceanographic Fleet, onboard #pourquoipas + #nautile 084
Reposted by benoit ildefonseCNRS @cnrs.fr · 11/12/2024#EnDirectDesLabos🔎 Nouvelles actualités scientifiques 🔬, création de laboratoires 🧑🔬 annonce de prix 🥇... Retrouvez toutes les deux semaines les informations issues des laboratoires du @cnrs.bsky.social 👉 www.cnrs.fr/endirectdesl... 03816
Reposted by benoit ildefonseUniversité de Montpellier @umontpellier.bsky.social · 03/12/2024Universités en Danger 🚨 Présidentes & Présidents ont alerté le Ministre sur la situation financière intenable des universités, conséquence des mesures nationales prises par l’État sans qu’elles ne soient compensées 🔗 Récap sur @franceuniversites.bsky.social 👉 franceuniversites.fr/actualite/un... 1910
Reposted by benoit ildefonseCNRS @cnrs.fr · 03/12/2024#SciencesPourDemain Avec cette grande consultation citoyenne, le CNRS vous invite à partager vos réflexions sur la manière dont les sciences peuvent aider à façonner le monde de demain. Partagez vos idées en 3 minutes ! 👉 make.org/FR/consultat... 16330
