Communiqué OVPF-IPGP – 10/03/2026
🌋 1 site éruptif actif (flanc SSE)
✅ front du bras de coulée actif à ~1,7 km de la RN2
📈 inflation de l’édifice
📊 trémor globalement stable sur les dernières 24h
▶️ Niveau d’alerte : 2.1
▶️ Communiqué complet ici: www.ipgp.fr/volcanoweb/r...
Káldy et al, 2025. Funding supported by: project RINGEN - research infrastructure upgrade No CZ.02.1.01/0.0/0.0/16_013/0001792 and Education and project SYNERGYS - systems for energy synergies No CZ.10.02.01/00/22_002/0000172.
How well can we detect tiny, human-made earthquakes?
Káldy et al, answer this question by testing automatic earthquake detection and localization with synthetic seismograms: a powerful validation tool!
Read more: doi.org/10.26443/sei...
Schematic illustration of the OHA-GEODAMS seafloor observatory. Credit: J.-A. Olive (LG-ENS) & J.-Y. Royer (Geo-Ocean)
If it all goes well, our now-complete observatory will be the first to document seafloor spreading and transform faulting events with geodesy, hydro-acoustics, and seismology! 🤞
An A-0-A pressure sensor, encased in a frame attached to four buoys floating on the ocean surface, waiting to be picked up. Credit: J.-A. Olive, LG-ENS / FOF
Last, but not least, we also recovered and re-deployed an A-0-A pressure sensor, right in the middle of the ridge's axial valley. This state-of-the-art instrument corrects its own drift by regularly re-calibrating itself against an inner chamber where the pressure is known.
Water color drawing of an acoustic transponder at the seafloor. Credit: J.-A. Olive, LG-ENS
But last week we succeeded in recovering and re-deploying 1 beacon from the ridge network, and 1 from the transform network. The first year of data did not disappoint! #ToBeContinued
2 iXblue/Exail Canopus acoustic transponders encased in yellow floats, atop 2-m tall metal tripods, waiting to be deployed on the back deck of R/V Marion Dufresne during the 2024 GEODAMS cruise. Credit: J.-A. Olive, LG-ENS / FOF
The core of the OHA-GEODAMS project is to measure active deformation for 3 years on the Southeast Indian Ridge and the Amsterdam transform fault. To this end, in February 2024, we deployed 15 acoustic beacons that have been pinging each other every few hours ever since.
@sismolise.bsky.social and @jaodynamics.bsky.social trying to figure out the most efficient schedule of operations in front of a post-it-covered whiteboard
a whiteboard covered in colored post-it notes representing the order of our instrument recoveries and deployments
Planning our upcoming deployments like they schedule sketches on Saturday Night Live
(with multiple new versions since that v1 😜) #GEODAMS
a hydrophone encased in an orange float just surfaced right in front of the R/V Marion Dufresne, on a calm sea. Credit: J.-A. Olive, LG-ENS / FOF
We also recovered and redeployed five hydrophones that were first deployed last year during the #GEODAMS 2024 cruise.
water color by D. Pacaud illustrating the deployment of an ocean bottom seismometer from the Marion Dufresne
We deployed 7 Ocean Bottom Seismometers (OBSs) to record earthquakes and other signals emitted by the Southeast Indian Ridge and the Amsterdam transform fault.
Julie & Jean-Arthur bringing the glider to the workboat for deployment. Credit: E. Klein
A few days ago, we deployed a Sea Explorer glider developed by ALSEAMAR and owned by ENSTA Bretagne at the location of our first hydrophone, southeast of Amsterdam island.
Data coming live from the ship's multibeam echosounder
As we make our way to our study area, we map the seafloor under the ship! 🌊 Our multibeam echosounder sends acoustic waves to the ocean floor and records how much time they take to bounce back.
Getting closer to our site!
Yesterday @geodams.bsky.social
Group picture of the GEODAMS 2025 team, on the deck of R/V Marion Dufresne, in front of Crozet Island
Meet the #GEODAMS 2025 team! ⚒️ @earth-science.bsky.social Right to left, back to front 👇
the cliffs of Crozet's Possession Island. Credit: S. Furst
the spectacular cliffs of Crozet's East Island in the distance. Credit: S. Furst
curious penguins swimming all around the ship. Credit: S. Furst
Today we were treated to spectacular views of Crozet's Possession Island and East Island, while the local penguins put on quite a show! 🐧🌤️⛰️
The R\V Marion Dufresne making its way through some fog
Happy new year from the R\V Marion Dufresne! Our journey began last year on xmas day, by heading straight South from La Réunion to the Crozet Islands.
Our planned route across the Southern Indian Ocean. Credit: Claire Lo Monaco
Our target site is located on the Southeast Indian Ridge, near Amsterdam Island. But to get there, the R/V Marion Dufresne will first loop across the Southern Indian Ocean to do all kinds of oceanographic and geochemical measurements, and swing by the Crozet Islands and Kerguelen. #OBSAustral2025
Schematic overview of the OHA-GEODAMS observatory. Credit: J.-A. Olive & J.-Y Royer
The goal of #GEODAMS is to deploy and maintain the first-of-its-kind seafloor seismo-geodetic observatory across a mid-ocean ridge and adjacent transform fault, to document seafloor spreading as it happens on a time scale of a few years.
starry night from the deck of the R/V Marion Dufresne
turns out the R/V Marion Dufresne is a spaceship
a cloudy sunset from the R/V Marion Dufresne
Hi! We are the OHA-GEODAMS team, a research project documenting how the Indian Ocean grows in (almost) real time. Between 2024 and 2027, we'll have 4 cruises to maintain a seafloor seismo-geodetic observatory across the Southeast Indian Ridge. We just started cruise #2, follow our adventures here!
