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The aim of this study is to assess the importance of geotourism before, during and after the eruption of the Tajogaite Volcano (September to December 2021) on La Palma, Spain. The methodology applied consisted of identifying the geotourism products on the island before the eruption, the importance of the volcano for geotourism – by means of a survey – and the geotourism products developed after the eruption. The findings show that, before the eruption, La Palma's tourism products (hiking, archaeology, stargazing and volcano tourism) were closely related to its volcanic heritage. During the eruption, Tajogaite became a tourist attraction for the island, drawing thousands of visitors and scientists. Lastly, now that the eruption has ended, geotourism is playing a key role in the various island recovery plans through the evaluation of sites of geotourism interest and the design of geotrails in natural and urban areas.

We report in-plume carbon dioxide (CO 2) concentrations and carbon isotope ratios during the 2021 eruption of Tajogaite volcano, island of La Palma, Spain. CO 2 measurements inform our understanding of volcanic contributions to the global climate carbon cycle and the role of CO 2 in eruptions. Traditional ground-based methods of CO 2 collection are difficult and dangerous, and as a result only about 5 % of volcanoes have been directly surveyed. We demonstrate that unpiloted aerial system (UAS) surveys allow for fast and relatively safe measurements. Using CO 2 concentration profiles we estimate the total flux during several measurements in November 2021 to be 1.76±0.20×103 to 2.23±0.26×104 t d -1. Carbon isotope ratios of plume CO 2 indicate a deep magmatic source, consistent with the intensity of the eruption. Our work demonstrates the feasibility of UASs for CO 2 surveys during active volcanic eruptions, particularly for deriving rapid emission estimates. [ABSTRACT FROM AUTHOR]

Historic volcanic activity in Tenerife was concentrated within two of the island's three dorsals and on the Teide-Pico Viejo complex located inside Las Cañadas caldera. Eruptions on the island are primarily characterised by basaltic and trachybasaltic fissural eruptions. However, the Teide-Pico Viejo complex also hosted explosive and effusive phonolitic eruptions. Our study focused on the analysis of the 2004-2005 unrest in Tenerife, which was characterised by an onset of a ground deformation pattern, heightened on-land seismic activity, changes in the chemical composition of fumaroles of the Teide composite volcano, an increase in diffusive emissions of carbon dioxide along the NW rift, and, significant gravity changes. We used the Envisat-ASAR satellite images from 2003 to 2010 to generate the Line-Of-Sight SBAS- DInSAR deformation time series to investigate the source responsible for ground deformation. We applied the Independent Component Analysis (ICA) to separate distinct ground deformation patterns. Specifically, we selected four components for the Independent Component Analysis decomposition: the first one mainly affects the stratovolcano's summit region of Teide and shows a circular symmetry; the second and third components are possibly related to the topography and atmospheric artifacts, while the fourth contains only a noisy signal. We employed a non-linear optimisation approach in a Finite Element modelling environment to determine the source geometry responsible for the first identified ICA pattern of ground deformation within Las Cañadas. Our results revealed the existence of an ellipsoidal ground deformation source oriented along the E-W axis, located beneath the Teide and Montaña Blanca volcanoes at 1,600 m a.s.l. This source became active during the seismic crisis of 2004-2005, which was associated with the degassing of a magma batch that intruded into the northwest rift of Tenerife island. We propose that the ground deformation observed at Teide volcano during the 2004-2005 crisis was related to hydrothermal activity within the volcano. [ABSTRACT FROM AUTHOR]

Biodigestion in farming and agriculture offers environmental and economic benefits, but investing in biodigesters carries real-world risks for enterprises. This study analyzes methane (CH4) emissions from a poultry farm biodigester in Tenerife Island, Canary Islands, Spain, conceptualized as a right-angled prism measuring 45 m wide, 25 m long, and 12 m tall, with an internal volume of approximately 13,500 m3. Using a Neon tracer gas technique, CH4 emission rates were quantified in situ during two surveys in February 2021 and October 2022, capturing seasonal variability in ambient conditions. Biogas analysis was performed using a portable micro-gas chromatograph in less than 5 min, revealing stable CH4 production rates of approximately 200 kg·d−1 (~310 m3·d−1) and 330 kg·d−1 (~500 m3·d−1) for the two experiments, respectively. The composition of biogas indicated CH4 concentrations of around 38–43%, with the remaining composition consisting of carbon dioxide (19–26%), nitrogen (36–27%), oxygen (7–4%), and trace amounts of other gases. A comparison with a theoretical model showed a good correlation. This approach enhances biodigester investment attractiveness by enabling enterprises to optimize efficiency promptly. The obtained data were used to estimate the energy potential of biogas from chicken farms in the Canary Islands. [ABSTRACT FROM AUTHOR]

At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO2 in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset. Before and during the occurrence of the October 2011–March 2012 submarine of El Hierro, Canary Islands, more than 8500 soil He analyses and diffuse CO2 emission measurements were performed. The results show that the soil He/CO2 emission ratio began increasing drastically one month before eruption onset, reaching the maximum value 10 days before. During the eruptive period, this ratio also showed a maximum value several days before the period with the highest magma emission rate. The He/CO2 ratio was also helpful in forecasting the eruption onset. We demonstrate that this tool can be applied in real-time during volcanic emergencies. Our results also encourage a reevaluation of the global He emission from the subaerial volcanism. [ABSTRACT FROM AUTHOR]

We report in-plume carbon dioxide (CO2) concentrations and isotope ratios during an active eruption of the Tajogaite Volcano. CO2 measurements inform our understanding of volcanic contributions to the global climate carbon cycle, and the role of CO2 in eruptions. Traditional ground-based methods of CO2 collection are difficult and dangerous, as a result only 5% of volcanoes have been surveyed. We demonstrate that Unpiloted Aerial System (UAS) surveys allow for fast and relatively safe measurements. Using CO2 concentration profiles we estimate total flux to be 1.19x106 to 2.80x107 t day-1. Isotope ratios indicated a deep magmatic source, consistent with the intensity of the eruption. Our work demonstrates the feasibility of UASs for CO2 surveys during active volcanic eruptions, particularly in calculating plume characteristics. [ABSTRACT FROM AUTHOR]