Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

Volcanic activity is always accompanied by the transfer of heat from the Earth’s crust to the atmosphere. This heat can be measured from space and its measurement is a very useful tool for detecting volcanic activity on a global scale. MIROVA (Middle Infrared Observation of Volcanic Activity) is an automatic volcano hot spot detection system, based on the analysis of MODIS data (Moderate Resolution Imaging Spectroradiometer). The system is able to detect, locate and quantify thermal anomalies in near real-time, by providing, on a dedicated website (www.mirovaweb.it), infrared images and thermal flux time-series on over 200 volcanoes worldwide. Thanks to its simple interface and intuitive representation of the data, MIROVA is currently used by several volcano observatories for daily monitoring activities and reporting. In this paper, we present the architecture of the system and we provide a state of the art on satellite thermal data usage for operational volcano monitoring and research. In particular, we describe the contribution that the thermal data have provided in order to detect volcanic unrest, to forecast eruptions and to depict trends and patterns during eruptive crisis. The current limits and requirements to improve the quality of the data, their distribution and interpretation are also discussed, in the light of the experience gained in recent years within the volcanological community. The results presented clearly demonstrate how the open access of satellite thermal data and the sharing of derived products allow a better understanding of ongoing volcanic phenomena, and therefore constitute an essential requirement for the assessment of volcanic hazards

Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

Volcanic activity is always accompanied by the transfer of heat from the Earth's crust to the atmosphere. This heat can be measured from space and its measurement is a very useful tool for detecting volcanic activity on a global scale. MIROVA (Middle Infrared Observation of Volcanic Activity) is an automatic volcano hot spot detection system, based on the analysis of MODIS data (Moderate Resolution Imaging Spectroradiometer). The system is able to detect, locate and quantify thermal anomalies in near real-time, by providing, on a dedicated website (www.mirovaweb.it), infrared images and thermal flux time-series on over 200 volcanoes worldwide. Thanks to its simple interface and intuitive representation of the data, MIROVA is currently used by several volcano observatories for daily monitoring activities and reporting. In this paper, we present the architecture of the system and we provide a state of the art on satellite thermal data usage for operational volcano monitoring and research. In particular, we describe the contribution that the thermal data have provided in order to detect volcanic unrest, to forecast eruptions and to depict trends and patterns during eruptive crisis. The current limits and requirements to improve the quality of the data, their distribution and interpretation are also discussed, in the light of the experience gained in recent years within the volcanological community. The results presented clearly demonstrate how the open access of satellite thermal data and the sharing of derived products allow a better understanding of ongoing volcanic phenomena, and therefore constitute an essential requirement for the assessment of volcanic hazards. Peer reviewe

Volcanic activity controls cholera outbreaks in the East African Rift

International audienceWe hypothesized that Cholera (Vibrio cholerae) that appeared along Lake Kivu in theAfrican Rift in the seventies, might be controlled by volcano-tectonic activity, which, byincreasing surface water and groundwater salinity and temperature, may partly rule thewater characteristics of Lake Kivu and promote V. cholerae proliferation. Volcanic activity(assessed weekly by the SO2 flux of Nyiragongo volcano plume over the 2007–2012 period)is highly positively correlated with the water conductivity, salinity and temperature of theKivu lake. Over the 2007–2012 period, these three parameters were highly positively correlatedwith the temporal dynamics of cholera cases in the Katana health zone that border thelake. Meteorological variables (air temperature and rainfall), and the other water characteristics(namely pH and dissolved oxygen concentration in lake water) were unrelated to choleradynamics over the same period. Over the 2016–2018 period, we sampled weekly lake watersalinity and conductivity, and twice a month vibrio occurrence in lake water and fish. Theabundance of V. cholerae in the lake was positively correlated with lake salinity, temperature,and the number of cholera cases in the population of the Katana health zone. V. choleraeabundance in fishes was positively correlated with V. cholerae abundance in lakewater, suggesting that their consumption directly contaminate humans. The activity of thevolcano, by controlling the physico-chemical characteristics of Lake Kivu, is therefore amajor determinant of the presence of the bacillus in the lake. SO2 fluxes in the volcanoplume can be used as a tool to predict epidemic risks