MACIV-nodes : An exceptional seismological network on the volcanoes of the Massif Central

As part of the MACIV project, funded by the French National Research Agency (ANR), a team of scientists deployed in September 2025 the largest mobile seismological network ever installed by a university team. This exceptional setup of 624 sensors, covering an area of 80 × 100 km² in the heart of the Massif Central, aims to image volcanic systems in fine detail from 0 to 10 km depth.



From September 15 to 24, 2025, fourteen engineers, PhD students, and researchers from various laboratories, including the Institut des Sciences de la Terre ISTerre-OSUG, CNRS / IRD / UGA / Univ. Savoie Mont-Blanc / Univ. Gustave Eiffel) [1] , installed this network. Composed of 624 sensors spread over an 80 × 100 km² area, the system is designed to image potentially active volcanic systems in the Massif Central, such as the Chaîne des Puys and the Monts-Dore, whose last eruptions occurred less than 10,000 years ago.
ISTerre teams involved in the September and November missions of the MACIV project



Projet ANR MACIV – Carte du réseau de capteurs (installation septembre, récupération novembre).

An unprecedented campaign to probe the Earth in depth

Installed in just 7.5 days, the sensors will record ground motion until their retrieval one month later. This ultra-dense array will provide a detailed image of volcanic systems from 0 to 10 km depth. It complements the permanent broadband networks of the RLBP – Epos-France, as well as temporary networks using instruments from the SisMob – Epos-France pool.

Thanks to ISTerre’s Geophysical Instrumentation Service, a new technological milestone has been reached in experimental seismology, with the development of innovative methods for geolocation and automatic metadata retrieval. These data will help improve understanding of intra-plate volcanism in the Massif Central and refine the characterization of regional seismicity.

By the end of October 2025, 621 of the 624 instruments were retrieved in less than a week by six teams of two people each.

Local Scientific Contacts

– Anne Paul, CNRS Researcher at the Institut des Sciences de la Terre(ISTERRE-OSUG)

This news was originally published by CNRS-INSU.

[1] CNRS Laboratories Involved
Laboratory of Magmas and Volcanoes (LMV – OPGC, CNRS / IRD / UCA)
Geosciences and Environment Laboratory, Toulouse (GET – OMP, CNRS / CNES / IRD / University of Toulouse)
Institute for Research in Astrophysics and Planetology (IRAP – OMP, CNRS / CNES / University of Toulouse)