Monitoring and forecasting Etna volcanic plumes

In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i) downloading weather forecast data from meteorological mesoscale models; ii) running models of tephra dispersal, iii) plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv) publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed

A Statistical Approach to Evaluate the Tephra Deposit and Ash Concentration from Puff Model Forecasts

In this paper we present a new statistical approach able to provide tephra deposit load and ash concentration using PUFF, a lagrangian model widely used to forecast volcanic ash dispersal during volcanic crisis. We perform a parametric study in order to analyze the influence of each input parameter on model outputs. For this test, we simulate two eruptive scenarios like to the 2001 (Scenario 1) and 1998 (Scenario 2) Etna eruptions using high resolution weather data and a domain of 170 x 170 km. Results show that for both scenarios, we are able to calculate the tephra deposit load and ash concentration but the use of millions of particles is required. Specifically, up to 33 and 220 millions of particles were necessary to accurately predict the tephra deposit and ash concentration in air, respectively. This is approximately two orders of magnitude larger than values typically considered running PUFF. The parametric study shows that the horizontal diffusion coefficient, the time step of the simulations, the topography and the standard deviation of the particle distribution greatly affect the model outputs. We also validate the model by best fit procedures. Results show a good comparison between field data of the 2001 Etna eruption and PUFF simulations, being inside 5 and 1/5 times the observed data, comparable with results of Eulerian models. This work will allow to reliably outlining the areas of contaminated airspace using PUFF or any other lagrangian model in order to define the No Fly Zone and ensure the safety to aviation operations as required after the Eyjafjallajökull eruption

Aircraft observations and model simulations of concentration and particle size distribution in the Eyjafjallajökull volcanic ash cloud

The Eyjafjallajökull volcano in Iceland emitted a cloud of ash into the atmosphere during April and May 2010. Over the UK the ash cloud was observed by the FAAM BAe-146 Atmospheric Research Aircraft which was equipped with in-situ probes measuring the concentration of volcanic ash carried by particles of varying sizes. The UK Met Office Numerical Atmospheric-dispersion Modelling Environment (NAME) has been used to simulate the evolution of the ash cloud emitted by the Eyjafjallajökull volcano during the period 4–18 May 2010. In the NAME simulations the processes controlling the evolution of the concentration and particle size distribution include sedimentation and deposition of particles, horizontal dispersion and vertical wind shear. For travel times between 24 and 72 h, a 1/t relationship describes the evolution of the concentration at the centre of the ash cloud and the particle size distribution remains fairly constant. Although NAME does not represent the effects of microphysical processes, it can capture the observed decrease in concentration with travel time in this period. This suggests that, for this eruption, microphysical processes play a small role in determining the evolution of the distal ash cloud. Quantitative comparison with observations shows that NAME can simulate the observed column-integrated mass if around 4% of the total emitted mass is assumed to be transported as far as the UK by small particles (< 30 μm diameter). NAME can also simulate the observed particle size distribution if a distal particle size distribution that contains a large fraction of < 10 μm diameter particles is used, consistent with the idea that phraetomagmatic volcanoes, such as Eyjafjallajökull, emit very fine particles

Characterising downwind particulate and sulfur dioxide air pollution from volcanic emissions

One of the hazards of volcanic eruptions is the emission of gas and aerosol into the atmosphere, which can cause damage to the environment and human health as well as impacting climate. Emissions from effusive volcanic eruptions and passively degassing volcanoes typically remain in the troposphere where they are advected by the wind and can cause deterioration to air quality across a downwind region. Of the emitted gases, sulfur dioxide (SO2) is often highly concentrated with respect to the background atmosphere and has important air quality and environmental consequences. Over time after emission from the volcanic source, SO2 may be converted to sulfate aerosols through atmospheric processes, leading to additional air quality concerns with an increase in fine particulate matter (PM). This thesis aims to characterise the SO2 and PM air quality in regions downwind of tropospheric volcanic emissions. Three study sites are examined; Kılauea volcano on the Island of Hawai‘i, Masaya volcano in Nicaragua and Fagradalsfjall volcano in Iceland. The SO2 and PM concentrations in the downwind regions are monitored using highly accurate reference-grade air quality instruments, and a variety of lower-cost miniaturised sensors. Low-cost sensors are increasingly used for air quality measurements, and in this thesis I investigate their effectiveness for monitoring in volcanic environments. Low-cost sensors are used at Masaya volcano as a first-attempt to establish an air quality monitoring network. At Kılauea volcano, a long time-series of SO2 and PM data is examined to determine air quality deterioration during a period of extremely heightened volcanic activity. At Fagradalsfjall volcano, the impact of a small eruption in proximity to densely-populated areas is examined and the population exposure to volcanic SO2 is estimated using a plume dispersion model. These studies increase the knowledge of SO2 and aerosol dispersal from volcanic sources, especially for those communities in the affected areas

An interdisciplinary study of the hazards associated with an AD1754 style eruption of Taal Volcano, Philippines

Taal Volcano, 60 km south of Metro Manila in Batangas Province, is one of the most active volcanoes in the Philippines. With 33 known eruptions, Taal has caused tremendous impacts on lives, property, economy and environment. The exposure of people and assets around Taal has increased greatly in recent years with around two million people living within a 35 km radius all at risk to volcanic hazards. The risk from Taal poses multiple challenges for local volcano disaster risk reduction (DRR) efforts. This interdisciplinary study combines a synthesis and critical review of historical eruptions of Taal; physical studies (geologic mapping, stratigraphic analyses and grain size measurements of the AD1754 tephra deposit); reconstruction of tephra dispersal for the AD1754 Plinian event using TEPHRA2 inversion modelling; and consideration of the social aspects of volcanic hazard and risk (e.g. socio-economic, political and DRR contexts for Batangas Province, and a pilot study assessing the knowledge, education, awareness and preparedness of Barangay Captains who are responsible for local level volcano disaster preparedness and response). Key outputs of the research include: 1) the first single, comprehensive chronology of identified historical eruptions of Taal; 2) discovery, mapping and sampling of 41 suspected AD1754 tephra outcrops; 3) first detailed field-based verification of two of the four identified phases of this event; 4) determination of likely eruption source parameters for the AD1754 event and new tephra dispersal isopachs through inversion modelling; and 5) preliminary insights into the knowledge, awareness and preparedness of the Barangay Captains, which show that while they do take volcanic risk seriously, they are ill-prepared to effectively support their communities in the case of a major volcanic crisis at Taal. The results and recommendations are aimed at strengthening volcano disaster risk management plans for Batangas Province

Coexisting with volcanoes : the relationships between La Soufrière and the society of St. Vincent, Lesser Antilles

Human population growth has resulted in increased numbers of people living in areas prone to disasters. Exploring the historical and social context of how volcanoes and their eruptions influence society in different socioeconomic and cultural ways over time helps us to understand the present-day challenges faced by those living in an active volcanic environment. La Soufrière volcano, on the island of St. Vincent, has erupted frequently in the recorded history of the Lesser Antilles. The three eruptions investigated (1812, 1902- 1903 and 1979) occur at three distinct stages of societal development: during the slavery era, post-emancipation and on the eve of independence. These distinct stages enable the investigation of how eruptions of La Soufrière highlighted social issues relevant to each time period. A mixed methodologies approach was used to explore how the society of St. Vincent has come to coexist with the low-frequency, high impact events of La Soufrière through time. The impact of the eruptions was mainly dependent on magnitude and longevity. This study shows the differences between VEI 4 and VEI 3 eruptions on the island and the control of topography on PDCs and lahars. It presents the most detailed chronology of the 1812 event to date and reveals previously overlooked aspects of 1902 eruptive activity of inland- direct base surges and a volcanogenic landslide. The mismatch effect is explored in how people experienced and recollected the 1979 eruption. This study finds that the volcanic hazard impacts occurred in the same places for the three eruptions but, damage to the agricultural sector was not homogenous. The differences lay within the socioeconomic structure of the agricultural systems between each eruption and consequent recovery options available. Furthermore, the volcanic hazard impacts, St. Vincent’s smallness, social capital and opportunities influenced whether people returned to their homes, stayed in evacuated locations or migrated off island. The island also shares typical coping adaptive strategies of Small Island Developing States (SIDS) such as migration/resettlement within and off the island and, temporary and permanent abandonment, which evolved from the loss of indigenous knowledge. This study demonstrates the importance of combining physical and social science to understand the complex interactions between volcanoes and people that lead to coexistence

Applications of the PUFF model to forecasts of volcanic clouds dispersal from Etna and Vesuvio.

PUFF is a numerical volcanic ash tracking model developed to simulate the behaviour of ash clouds in the atmosphere. The model uses wind field data provided by meteorological models and adds dispersion and sedimentation physics to predict the evolution of the cloud once it reaches thermodynamic equilibrium with the atmosphere. The software is intended for use in emergency response situations during an eruption to quickly forecast the position and trajectory of the ash cloud in the near (~1-72 hour) future. In this paper we describe the first application of PUFF model in forecasting volcanic ash dispersion from the Etna and Vesuvio volcanoes. We simulated the daily occurrence of an eruptive event of Etna utilizing ash cloud parameters describing the paroxysm of 22nd July 1998 and wind field data for the 1st September 2005 - 31st December 2005 time span from the Global Forecast System (GFS) model at the approximate location of Etna volcano (38N 15E). The results show that the volcanic ash particles are dispersed in a range of directions in response to changing wind field at the various altitudes and that the ash clouds are mainly dispersed toward the east and southeast, although the exact trajectory is highly variable, and can change within of a few hours. We tested the sensitivity of the model to the mean particle grain size and found that an increased concentration of ash particles in the atmosphere results when the mean grain size is decreased. Similarly, a dramatic variation in dispersion results when the logarithmic standard deviation of the particle size distribution is changed. Additionally, we simulated the occurrence of an eruptive event at both Etna and Vesuvio, using the same parameters describing the initial volcanic plume, and wind field data recorded for 1st September 2005, at approximately 38N 15E for Etna and 41N 14E for Vesuvio. The comparison of the two simulations indicates that identical eruptions occurring at the same time at the two volcanic centres display significantly different dispersal axes as a consequence of the different local wind field acting at the respective eruptive vent. At Vesuvio volcano, a plinian eruptive event with the dynamical parameters of the 79 A.D. eruption was simulated daily for one year, from 1st July 2005 to 30th June 2006. The statistical processing of results points out that, although in most cases the ash cloud dispersal encompasses many different areas, generally the easterly-southeasterly direction is preferred. Our results highlight the significant role of wind field trends in influencing the distribution of ash particles from eruptive columns and prove that the dynamical parameters that most influence the variability of plume dispersal are the duration of the eruption and the maximum column height. Finally, the possible use of cloud simulations for refining hazard maps of areas exposed to volcanic ash dispersal is proposed

Online learning of physics during a pandemic: A report from an academic experience in Italy

The arrival of the Sars-Cov II has opened a new window on teaching physics in academia. Frontal lectures have left space for online teaching, teachers have been faced with a new way of spreading knowledge, adapting contents and modalities of their courses. Students have faced up with a new way of learning physics, which relies on free access to materials and their informatics knowledge. We decided to investigate how online didactics has influenced students’ assessments, motivation, and satisfaction in learning physics during the pandemic in 2020. The research has involved bachelor (n = 53) and master (n = 27) students of the Physics Department at the University of Cagliari (N = 80, 47 male; 33 female). The MANOVA supported significant mean differences about gender and university level with higher values for girls and master students in almost all variables investigated. The path analysis showed that student-student, student-teacher interaction, and the organization of the courses significantly influenced satisfaction and motivation in learning physics. The results of this study can be used to improve the standards of teaching in physics at the University of Cagliar

Maritime expressions:a corpus based exploration of maritime metaphors

This study uses a purpose-built corpus to explore the linguistic legacy of Britain’s maritime history found in the form of hundreds of specialised ‘Maritime Expressions’ (MEs), such as TAKEN ABACK, ANCHOR and ALOOF, that permeate modern English. Selecting just those expressions commencing with ’A’, it analyses 61 MEs in detail and describes the processes by which these technical expressions, from a highly specialised occupational discourse community, have made their way into modern English. The Maritime Text Corpus (MTC) comprises 8.8 million words, encompassing a range of text types and registers, selected to provide a cross-section of ‘maritime’ writing. It is analysed using WordSmith analytical software (Scott, 2010), with the 100 million-word British National Corpus (BNC) as a reference corpus. Using the MTC, a list of keywords of specific salience within the maritime discourse has been compiled and, using frequency data, concordances and collocations, these MEs are described in detail and their use and form in the MTC and the BNC is compared. The study examines the transformation from ME to figurative use in the general discourse, in terms of form and metaphoricity. MEs are classified according to their metaphorical strength and their transference from maritime usage into new registers and domains such as those of business, politics, sports and reportage etc. A revised model of metaphoricity is developed and a new category of figurative expression, the ‘resonator’, is proposed. Additionally, developing the work of Lakov and Johnson, Kovesces and others on Conceptual Metaphor Theory (CMT), a number of Maritime Conceptual Metaphors are identified and their cultural significance is discussed