Abstract We present the IMAGMASEIS project, a large-N seismic experiment carried out on La Palma (Canary Islands, Spain) between 2023 and 2024, aimed at high-resolution imaging of the crustal and upper mantle structure using passive seismic methods. The project involved the deployment of 235 temporary broadband and short-period seismic stations, supplementing 21 permanent stations, thus creating the densest seismic network ever installed on the island. The main goal is to characterise the magmatic plumbing system beneath Cumbre Vieja volcano, identify magma accumulation zones, and investigate structural changes related to the 2021 Tajogaite eruption. We describe the experimental design, network configuration, instrumentation, deployment strategies, and challenges encountered, including difficult terrain and logistical constraints. Preliminary results demonstrate the potential of the dataset for ambient noise tomography, receiver function analysis, and local earthquake studies. IMAGMASEIS provides a valuable resource for understanding volcanic and tectonic processes in oceanic island settings and serves as a model for cost-effective, high-density seismic deployments in similar environments.

Abstract Waves transport energy through the atmosphere without transporting mass. Often excited in the troposphere, they can propagate horizontally and vertically over long distances, depending on the type of wave and the background atmosphere. The fastest atmospheric waves are (infra)sound and acoustic gravity waves. The list of possible reasons for the generation of these atmospheric waves is not short; here, we concentrate on natural hazards. Due to their comparatively high propagation speed, infrasound and acoustic gravity waves can contribute to or even improve early warning of natural hazards, even when measured at high altitudes. Traditionally, each scientific community—the one that deals with the neutral atmosphere and the one that addresses the ionosphere—usually works on its own. The aim of this manuscript is to bring together observations and results from both communities. The main challenges of the respective communities with regard to the use of these waves in the context of early warning of natural hazards are identified.

Abstract The Lousal Mine (Iberian Pyrite Belt, Portugal) was operated from 1900 to 1988 for the extraction of massive sulphides and was later rehabilitated as a science museum. It was selected as a test site for underground muon tomography applied to geophysical surveys, as part of the LouMu project. This study focuses on seismic tomography to analyse the subsurface above the mine gallery, primarily surveyed by a muography telescope, which was developed specifically for this site by the Laboratory of Instrumentation and Experimental Particle Physics. To validate the muon tomography results, an initial approach using conventional 2D seismic refraction failed to reach the Waldemar gallery depth, due to limited seismic ray coverage. Therefore, an innovative setup using surface shots and in-gallery geophones was implemented, providing full ray coverage. A 3D velocity model was then produced using the ATOM3D code, which enabled the integration of this configuration and performed travel-time inversion for velocity calculation. A regional dextral strike-slip fault, the Corona Fault (CF), crosses the surveyed area, and served as the main focus of this investigation. The 3D velocity model successfully detected this structure, that corresponded to the boundary between positive anomalies of the Volcano-Sedimentary Complex (VSC) and negative anomalies of the Phyllite-Quartzite Group (PQG). The absolute velocity distribution showed a distinct offset around the Corona Fault (CF), indicating a dextral strike-slip mechanism. A subvertical extension of secondary faults was observed, reflecting deformation similar to that of the main tectonic context. Previous data from the gallery confirmed that these results are consistent with the known geology and can serve as a reference for the muon tomography interpretations.