High-resolution aeromagnetic survey over the Tajogaite Volcano, La Palma, Canary Islands

A high-resolution aeromagnetic survey using a drone was conducted in June 2024 over the Tajogaite volcano on La Palma, Canary Islands. This survey aims to characterise thermal anomalies associated with magma intrusion and the related fault system.

The drone was equipped with a fluxgate magnetometer operating at a sampling rate of 200 Hz, with two sensors separated by 1 m. The constant altitude flights covered approximately a 2.5 km x 2.5 km area, with N-S lines spaced 30–60 m apart. The survey also included tie lines for quality control and calibration flights at very high altitude (low magnetic gradient) to account for the effects of drone pitch, roll, and yaw on magnetic measurements.

Data preprocessing included deriving the total magnetic field from its components, cleaning flight tracks, and compensating for drone-related influences using calibration data. A low-pass filter removed high-frequency noise from the drone’s electronics, and data from both sensors were averaged. Data from all flights were merged and interpolated using linear triangulation onto a 20 m grid with Gaussian smoothing. Diurnal corrections were considered unnecessary due to short flight durations and minimal diurnal variations at low latitudes. Magnetic anomalies were calculated by subtracting the median value from the processed magnetic map.

The new magnetic anomaly map provided critical insights into the thermal and structural characteristics of the volcanic system. This study is part of the GEOTHERPAL project, further detailed at http://pc213fis.fis.ucm.es/GEOTHERPAL/index.html.