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Pfanz, H.
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Pfanz, H.
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- PublicationOpen AccessGas hazard related to CO2 degassing at Loutra Ypatis, Greece(Geological Society of Greece, 2019-05-22)
; ; ; ; ; ; ; ; ; ; ; Earthquakes and volcanic eruptions represent a hazard. However, the impact of gases released in geodynamically active areas should not be underestimated. It is commonly known that geogenic sources release great amounts of gases, which, apart from having an important influence on the global climate, can also have a strong impact on human health causing both acute and chronic effects. In particular, CO2 and sulphur gases (mainly H2S and SO2) are the main compounds responsible for acute mortality due to their asphyxiating and/or toxic properties. One of the most known and also worst episodes occurred, took place on the 21th of August 1986 at Lake Nyos, Cameroon, when about 1700 people were killed and 850 injured by a massive CO2 release (D’Alessandro, 2006). Like other geodynamically active areas, Greece is also affected by a large number of geogenic gas manifestations (Daskalopoulou et al., 2018a). These occur either in the form of point sources (fumaroles, mofettes, bubbling gases) or of diffuse soil gas emanations (Daskalopoulou et al., 2018b). D’Alessandro and Kyriakopoulos (2013) made a preliminary estimation of the risk related to geogenic gases in Greece for the time period of 1992-2011; the whole population of the country was considered. In that period, at least two fatal episodes with a total of three victims took place, likely caused to the exposure to geogenic gases (specifically CO2). This would give a risk of 1.310-8 fatality from geogenic gas manifestations per annum. This value, although probably underestimated, is much lower than many other natural or anthropogenic risks. Since deaths due to natural gases are often wrongly attributed, it cannot be excluded that some fatal episode has not been recognized and thus that the risk is somewhat higher than assessed. Although very low, this risk should not be neglected, not only because it is possibly underestimated, but also because simple countermeasures could be adopted for risk reduction. Dangerous areas could be easily identified and delimited by geochemical prospecting and their hazards properly highlighted. Apart from the sites where fatal episodes occurred, many other hazardous sites have been recognized in Greece. Here we present data collected at Loutra Ypatis (central Greece). Study area Sperchios Basin – Evoikos Gulf Graben is a 130 km long actively spreading graben in Central Greece (1 cm/a). The high geothermal gradient of the area is evident by the presence of many thermal springs with temperatures that vary from 24 to 82 °C. In the waters of these springs, discharging along the normal faults bordering the graben, an abundant gas phase is bubbling. Loutra Ypatis is one of the emerging springs and its waters (31 °C) are exploited by a spa. The water is currently drained by a gallery and therefore the water level is about 5 m below ground at the bottom of a funnel-like hole (Fig. 1 left). For safety reasons the hole was covered by a closed building (Fig. 1 left and center). The gas, which is vigorously bubbling in the spring, is mostly (> 96%) composed of CO2 (D’Alessandro et al., 2014). The walls of the hole are covered of sulfur that derives from the partial oxidation of the H2S (2500 ppm) contained in the released gas (D’Alessandro et al., 2014).Methods In October 2015 atmospheric concentrations of CO2 were measured with a Licor LI820 NDIR spectrometer (range 0 to 20,000 ppm, accuracy of 2%), whilst in April 2016, the atmospheric concentrations of CO2 and H2S were measured with a Multi-GAS analyser manufactured by INGV-Palermo equipped with Licor LI-840 NDIR spectrometer (CO2 0-20,000 ppm) and an EZ3H electrochemical sensor by City Technology Ltd. (H2S 0–100 ppm). Simultaneous CO2, CH4 (both 0-100%), CO, H2S (both 0-500 ppm) and O2 (0 – 25%) concentrations within the building were measured with a portable gas analyser GA2000 (Geotechnical Instruments). Results and discussion Due to the fact that a building covers the thermal spring, the intense bubbling activity of its waters creates a strong gas accumulation inside. The main component of the released gases is CO2, which has a higher density with respect to atmospheric air, thus creating the conditions for gas accumulation. About 2 m above the water level, CO2 concentrations of >95% and non-detectable O2 concentrations were measured. At higher levels above the water, CO2 concentrations were decreased but never below 50%. Such concentrations within the building are lethal for both animals and human beings. Of course, access is forbidden, but as the building is not perfectly sealed, the gases permeate to the outside through fissures and cracks. Figure 2 shows the CO2 concentrations measured in the air on October 2015 at 1.5 m height while walking around the walls of the edifice at about 2 m distance. Leaking of CO2 from the edifice is made evident by concentrations reaching values of more than 6000 ppm. The highest values were measured close to the entrance of the edifice were fissures and cracks are concentrated. Due to the tendency of CO2 to accumulate at lower levels, in this place, close to the ground, CO2 levels lethal to small animal can be reached. This was made evident by a dead bird found in that occasion (Fig. 1). In April 2016, due to the much windier conditions, CO2 concentrations at the same places reached values never exceeding 1000 ppm while H2S was always below 1 ppm. These values sharply increased getting closer to the fissures around the main entrance of the building and reached saturation of the sensors (CO2 > 20,000 ppm and H2S > 100 ppm) at a distance of few centimeters. The intense CO2 degassing observed at Loutra Ypatis may be responsible for elevated levels that can have an impact on human beings. It is worth noting that values measured in the atmosphere close to the building exceed the Occupational Recommended Exposure Limit of 5000 ppm (NIOSH, 2005). In closed spaces lethal levels can be easily reached. An older inhabitant of the close by village told us that in his childhood a playmate died by going inside the gallery that drains the thermal water out of the spa due to the high CO2 levels. Such episode underscores the need not to disregard the gas hazard created by intense natural gas manifestations like the thermal spring of Loutra Ypatis.123 97 - PublicationRestrictedGeogenic emission of methane and carbon dioxide at beciu mud volcano, (berca-arbănaşi hydrocarbon-bearing structure, eastern carpathians, Romania)(2012-07-25)
; ; ; ; ;Frunzeti, N.; Babeş-Bolyai University, Faculty of Environmental Science and Engineering, Cluj-Napoca, Romania ;Baciu, C.; Babeş-Bolyai University, Faculty of Environmental Science and Engineering, Cluj-Napoca, Romania ;Etiope, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Pfanz, H.; Institute of Applied Botany, University of Duisburg-Essen, D-45117 Essen, Germany; ; ; As shown by previously performed flux measurements, the mud volcanoes of Berca-Arbănaşi hydrocarbon-bearing structure in Eastern Carpathians Foredeep, including Pâclele Mari, Pâclele Mici, and Fierbători, represent a main gas seepage system in Romania, with considerable emissions of methane. The present work completes these gas emission studies by reporting the flux of methane and carbon dioxide at Beciu mud volcano, belonging to the same structure, not measured previously. In total, 78 measurements were carried out in June 2011 (40 on the vents, 34 on the area covered by mud and 4 in the external area, covered by vegetation). Diffuse fluxes from mud were found ranging from 102 to 105 mg CH4 m-2 day-1, and 102-104 mg CO2 m-2 day-1; the emission from individual vents was in the range of 0.014 to 32 t CH4 year-1 and 0.003 to 2.9 t CO2 year-1. These values are comparable with those typically documented for mud volcanoes worldwide. Gas seepage occurs pervasively throughout the muddy cover, even if it appears to be saturated with water. The total emission of CH4 and CO2 from Beciu mud volcano is conservatively estimated to be at least 190 t year-1 and 35 t year-1, respectively. The Beciu output leads the total CH4 emission from the four Berca mud volcanoes to at least 1350 t year-1, a value comparable with that reported for a similar number of giant mud volcanoes in Azerbaijan. This work contributed to update the geogenic gas flux data-set of Romania and to extend the global data-set of methane and carbon dioxide emissions from mud volcanoes.197 31 - PublicationRestrictedThe Ancient Gates to Hell and Their Relevance to Geogenic CO2(Academic Press, 2014)
; ; ; ; ; ; ; ;Pfanz, H.; University of Duisburg-Essen, Campus Essen, Essen, Germany ;Yüce, G.; Hacettepe University, Ankara, Turkey ;D'Andria, F.; University of Salento, Italy ;D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Pfanz, B.; Ruhr-University, Bochum, Germany ;Manetas, Y.; University of Patras, Greece ;Papatheodorou, G.; University of Patras, Greece; ; ; ; ; ; ; ; ;Wexler, P.; National Library of MedicineNo abstract382 85 - PublicationOpen AccessInfrared remote sensing of Earth degassing - Ground study(2005)
; ; ; ; ;Tank, V.; Remote Sensing Technology Institute, German Aerospace Center, Wessling, Germany ;Pfanz, H.; Lehrstuhl für Angewandte Botanik/Ökophysiologie, Universität Duisburg-Essen, Germany ;Gemperlein, H.; Remote Sensing Technology Institute, German Aerospace Center, Wessling, Germany ;Strobl, P.; Remote Sensing Technology Institute, German Aerospace Center, Wessling, Germany; ; ; Geodynamical processes e.g., volcanoes, often cause degassing at the Earth surface. The geogas emanates via mineral springs, water mofettes, or dry mofettes. It is assumed that the emerging gas influences the temperature of the spring or mofette water, respectively and the surface temperature of the soil at and around the dry gas vents. This causes a thermal anomaly in comparison to the close vicinity. Under specific conditions this effect should be extractable from remotely acquired infrared images allowing detection, mapping and monitoring of gas vents/springs within large areas and short times. This article describes preparatory investigations for which emanating Earth gas was simulated by leading compressed air into the ground and releasing it in some depth via a metal lance. The thermal effect at the surface was observed from a nearby thermovision camera in summer and winter under varying meteorological conditions. A procedure was developed to reliably identify gas release areas within the recorded thermal images of the scene. The investigations are aiming at studies to be performed later in the Western Bohemia (Czech Republic) earthquake swarm region where especially CO2 of magmatic origin from European SubContinental Mantle (ESCM) emanates.186 689 - PublicationRestrictedCarbon dioxide and radon emissions from the soils of Pantelleria island (Southern Italy)(2018-08-15)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; In the period July 2005–October 2006 several soil gas prospections were performed on the island of Pantelleria, an active volcanic/geothermal system at present in a quiescent state. Measured parameters were CO2 concentrations and 220Rn and 222Rn activities at 50 cm depth and CO2 fluxes from the soil. The whole island was covered with a measurement density of 3.5 points/km2 for CO2 (flux and concentration) and 1.6 points/km2 for Rn. Further three main and seven minor areas of previously ascertained or expected exhalative activity were covered with a measurement density up to 100 points/km2. The obtained results ranged from 0.038 to 95%vol for CO2 concentration, from 10 Bq/m3 to 164,000 Bq/m3 from 10 Bq/m3 to 750,000 Bq/m3 for 220Rn and 222Rn activities, respectively and from <0.1 to 4700 g/m2 day for CO2 fluxes. Probability plots evidenced for all measured parameters the presence of three populations (background, mixed and hydrothermal). All anomalous values were found in the central part of the island within the youngest caldera. Flux data allowed us to estimate a total CO2 output of the volcanic/geothermal system of Pantelleria in 24.2 tons per day. Some new exhaling area, significantly contributing to the total output and characterised by stunted or absent vegetation, were evidenced on the southern flank of Mt. Grande. At one of these areas the relationships between the measured parameters and vegetation cover were studied in detail along a 140 m long transect of 15 points. Finally, a first evaluation of the gas hazard related to the geogenic degassing evidenced some high risk area at the mofette along the shores of the Lake Specchio di Venere (CO2) and in the village of Rekale (CO2 and Rn).824 15