<p>Cumbre Vieja is the most active volcano of the Canary Islands since it has been the scenario of  8 of 17 historical eruptions in this archipelago. A recent magmatic reactivation started at Cumbre Vieja volcano on October 2017, and 9 additional seismic swarms occurred until the recent eruption which started on September 19, 2021, and ended on December 13, 2022 after 85 days of eruption. Since the first day of the eruption, extending to current days, INVOLCAN performed the monitoring of SO<sub>2</sub> realesed by this eruption using a miniDOAS on terrestrial (car), sea (ship) and air (helicopter) mobile position. More than 360 measurements of SO<sub>2</sub> emission rates were carried out daily. The standard deviation of the estimated values obtained daily was ~ 20%. During the first days of the eruption, estimated SO<sub>2</sub> emission rates reached more than 30,000 tons/day, and maintaining weekly average values above 10,000 tons/day until the end of the eruption. After a final paroxysmal phase with an eruptive column of 8,500 m altitude, decreased significantly to averages values of 250 tons/day. Estimated SO<sub>2</sub> emission rates from the 2021 Cumbre Vieja eruption became a powerful tool to contribute to the understanding of eruptive dynamics.</p>

<p>La Palma Island (708 km<sup>2</sup>) is located at the north-west and is one of the youngest (~2.0My) of the Canarian Archipelago. The current stage of shield-building is manifest by the construction of Cumbre Vieja volcano, at the southern part of the island, where volcanic activity has taken place exclusively in the last 123 ka. On September 19, 2021, a new volcanic eruption occurred at Cumbre Vieja volcanic system (Tajogaite eruption). The erupting fissure (~1.0 km-length) is characterized by lava effusion, strombolian activity, lava fountaining, ash venting and gas jetting. After 85 days, the eruption finished on December 13, 2021. The 2021 Tajogaite eruption, with a magnitude VEI=3 (Bonadonna et al., 2022), resulted in the longest volcanic event on the island during the last 600 years and the most important eruption of Europe during the last 75 years.</p> <p>At the time of this study, the volcanic gas emissions observed at Tajogaite volcanic cone consisted mostly in diffuse CO<sub>2</sub> degassing and residual fumarolic activity. Here we report the first diffuse CO<sub>2</sub> and H<sub>2</sub>S emission surveys that have been carried out in Tajogaite volcanic cone.The measurements of soil CO<sub>2</sub> efflux have been performed following the accumulation chamber method in 94 sites and the spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) procedure to show the location of CO<sub>2</sub> and H<sub>2</sub>S diffuse degassing structures (DDS) and to quantify the diffuse CO<sub>2</sub> and H<sub>2</sub>S emission from the studied area. The diffuse CO<sub>2</sub> emission released to the atmosphere from Tajogaite volcanic cone ranged between 0 to 11.4 kgm<sup>-2</sup>·d<sup>-1</sup> with an average of 0.90 kgm<sup>-2</sup>·d<sup>-1</sup>. The main DDS was located in the easternmost area of ​​the cone. Regarding the diffuse H<sub>2</sub>S emission, the data ranged between 0 to 44. 7 kgm<sup>-2</sup>·d<sup>-1</sup> with an average value of 3.0 kgm<sup>-2</sup>·d<sup>-1</sup>. Two main DDS were identified: one coinciding with the CO<sub>2</sub> DDS, in the easternmost zone, and other in the northern area of the cone. This study represents a starting point to study the degassing of the residual magma bodies beneath Tajogaite volcanic cone.</p> <p>Bonadonna, C. et al. (2022), EGU22-11927, https://doi.org/10.5194/egusphere-egu22-11927.</p>

<p>Urban geoturism is a relatively recent type of tourism that has increased a lot in recent years. The elaboration of geotouristic trails is the main way to develop this type of tourism in cities. Urban geotourism aims at exploiting the cultural heritage (churches, hermitages, cemeteries, houses, squares, streets, etc.) and the urban layout itself. But too the geographical and natural elements (volcanoes, ravines, cliffs, beaches, dunes, etc.) that have not been wiped out by the urban growth and transformation processes. In this study we have chosen the old centre of las Palmas de Gran Canaria (LPGC) in Gran Canaria. The Canary Islands are an active volcanic region located in the Eastern Atlantic Ocean, about 100 km off the west coast of Africa and at a subtropical latitude. The choice of the city of LPGC is due to the fact that it is the main city of the Canary Islands (378.675 inhabitants) and has one of the oldest, largest and best preserved centers in the Canary Island. The aim of this work is to propose an urban geotourism itinerary through the historical centre of Vegueta and Triana neighbourhoods in LPGC city (Gran Canaria, Canary Islands, Spain). The methodology will consist of identifying, selecting and characterizing different geomorphosites in the city (cliffs, beaches, fossil dunes) and describing the main types of stone used for the construction and ornamentation of buildings from the foundation of the city in the 15th century to the present day. Based on the variety of resources identified and inventoried, we have proposed a geographical urban geotourism itinerary to satisfy and diversify the tourist offer of the city, which consists of 24 points distributed between the historic neighborhoods of Triana and Vegueta, in which elements of the volcanic heritage of the island and/or that present important natural and cultural value linked mainly to religious (10) and civil (15) heritage. This proposed route is of low difficulty and can be done in two hours. The material identified mainly in elements of the facades of the buildings is gray, white, and green ignimbrite and scoria volcanic rocks. Part of this material comes from the Tirma, Teror and Galdar quarries. Elements of sandstone, limestone, pumice, organogenic sand, boulders, red scoria were also identified, as well as structures with the presence of sandstone as cement. (Volturmac-MAC2/4.6c/298).</p>

<p>Anomalous CO<sub>2</sub> degassing of volcanic origin was observed by the end of November 2021 in the neighborhoods of La Bombilla and Puerto Naos, located in the western flank of La Palma, about 5 km distance southwestern of the 2021 Tajogaite eruption vents (Hernández et al., 2021). In this study zone, continuous monitoring of CO<sub>2</sub> concentration in the outdoors ambient air at 200 cm from the surface has reached a daily average of maximum and mean values about 28,000 and 10,000 ppm, respectively. We started recently to perform CO<sub>2</sub> concentration and stable isotope surveys in the outdoors ambient air of Puerto Naos at 140 cm from the surface by means of a Delta Ray analyzer installed in an electrical car which was driving through the streets of Puerto Naos. This instrument is a high performance, mid-infrared laser-based, isotope ratio infrared spectrometer (IRIS) which offers the possibility of performing simultaneous determination of δ<sup>13</sup>C and δ<sup>18</sup>O in CO<sub>2</sub> at ambient concentrations with a precision as low as 0.05‰. One major advantage of IRIS techniques with respect to more traditional ones (e.g., isotopic ratio mass spectrometry -IRMS-) is the possibility to perform (semi)continuous measurements at high temporal resolution. Since October 2022, seven surveys have been performed at Puerto Naos making up a total of about 600 measurements. The observed CO<sub>2</sub> concentrations and the δ<sup>13</sup>C-CO<sub>2</sub> values in the outdoors ambient air ranged from 420 to 3,500 ppm and from -9.0 to -3.2 ‰ vs. VPDB, respectively. Survey data analysis showed a good spatial correlation between relatively high CO<sub>2</sub> concentrations with δ<sup>13</sup>C-CO<sub>2</sub> values less <sup>13</sup>C-depleted (<em>i.e.</em>, volcanic CO<sub>2</sub>). These observations highlight that stable isotope surveys allow to evaluate the impact of volcanic degassing on the air CO<sub>2</sub> concentration and provide valuable results to identify the volcanic CO<sub>2</sub> gas hazard zones.</p><p>Hernández, P. A., Padrón, E., Melián, G. V., Pérez, N. M., Padilla, G., Asensio-Ramos, M., Di Nardo, D., Barrancos, J., Pacheco, J. M., and Smit, M.: Gas hazard assessment at Puerto Naos and La Bombilla inhabited areas, Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7705, https://doi.org/10.5194/egusphere-egu22-7705, 2022.</p>

<p>Carbon dioxide (CO<sub>2</sub>) is one of the first gases to escape from the magmatic environment due to its low solubility in basaltic magmas at low pressures. Monitoring of volcanic gases in Tenerife Island (2,304 km<sup>2</sup>) has been focused mainly on diffuse CO<sub>2</sub> degassing and other volatiles due to the absence of visible gas manifestations except fumaroles at the summit of Teide volcano. An inexpensive method to determine CO<sub>2</sub> fluxes based in the absorption of CO<sub>2</sub> through an alkaline medium followed by titration analysis has been used with the aim of contributing to the volcanic surveillance of Tenerife. During summer 2016, a network of 31 closed alkaline traps was deployed along the three volcanic rifts of Tenerife (NE, NW and NS) and at Cañadas Caldera. To do so, an aliquot of 50 mL of 0.1N KOH solution is placed inside the chamber at each station to absorb the CO<sub>2</sub> released from the soil. The solution is replaced in a weekly basis and the trapped CO<sub>2</sub> is later analyzed at the laboratory by titration. Values are expressed as weekly integrated CO<sub>2 </sub>efflux. We present herein the results of one year CO<sub>2 </sub>efflux estimated by closed alkaline traps. The CO<sub>2</sub> efflux values ranged from 1.0 to 14.5 g·m<sup>-2</sup>·d<sup>-1</sup>, with average values of 8.5 g·m<sup>-2</sup>·d<sup>-1</sup> for the NE rift-zone, 5.2 g·m<sup>-2</sup>·d<sup>-1 </sup>for Cañadas Caldera, 6.4 g·m<sup>-2</sup>·d<sup>-1</sup> for NW rift-zone and 6.1 g·m<sup>-2</sup>·d<sup>-1</sup> for NS rift-zone. The estimated CO<sub>2 </sub>efflux values were of the same order than the observed ones in 2016. Relatively high CO<sub>2</sub> efflux values were observed at the NE rift-zone, where maximum values were measured. The temporal evolution of CO<sub>2 </sub>efflux estimated by closed alkaline traps did not show significant variations during 2019. However, small seasonal variations are observed during the period 2016 – 2019. To investigate the origin of the soil CO<sub>2</sub>, soil gas samples were weekly sampled on the head space of the closed chambers. Chemical and isotopic composition of C in the CO<sub>2</sub> were analysed in the gas samples. The concentration of CO<sub>2</sub> on the head space of the closed chambers showed a range of 355-50,464 ppm, with an average value of 1,850 ppmV, while the isotopic composition expressed as d<sup>13</sup>C-CO<sub>2</sub> showed a range from -5.03 to -30.44 ‰, with an average value of -15.9 ‰. The heaviest values of d<sup>13</sup>C-CO<sub>2</sub> are in the NW rift-zone. The systematics of closed static chambers alkaline traps can be a simple and economical tool with volcanic surveillance purposes in system where visible volcanic gases manifestations are absence.</p>