Pre-Eruptive Inflation on La Palma (2014–2021): GNSS Evidence for Regional Magmatic Interactions in the Canary Islands

Prior to the Tajogaite eruption (19/09-13/12/2021), several unrest signals were detected on La Palma starting in 2017. In particular, seismic swarms associated with variations in gas emissions and ground deformation were documented between 2017 and the onset of the 2021 eruptive process (Torres-González et al., 2020; Fernández et al., 2021). However, the spatio-temporal relationship between the 2021 eruptive activity on La Palma and the regional tectonic framework of the Canary Archipelago has not yet been thoroughly investigated.

The joint analysis of regional- and local-scale continuous GNSS data from permanent open-access stations across the Canary Islands allowed the identification of anomalous inflation on La Palma beginning in 2014. This anomalous signal is temporally correlated with the cessation of sill intrusion events that drove the long-term uplift of El Hierro Island following its submarine eruption (2012–2014). Our analysis explores whether this inflation can be directly related to the Tajogaite eruption—suggesting that post-eruptive processes at El Hierro may have induced dilatation within La Palma’s magmatic plumbing system—or whether it reflects a broader regional uplift associated with deep intrusions and lateral magma transport across the Canary Archipelago.

References

Torres-González, P.A., Luengo-Oroz, N., Lamolda, H. et al. (2020) Unrest signals after 46 years of quiescence at Cumbre Vieja, La Palma, Canary Islands, J. Volcanol. Geotherm. Res., 392, 106757, https://doi.org/10.1016/j.jvolgeores.2019.106757.

Fernández, J., Escayo, J., Hu, Z. et al. (2021) Detection of volcanic unrest onset in La Palma, Canary Islands, evolution and implications. Sci. Rep., 11, 2540. https://doi.org/10.1038/s41598-021-82292-3.