# A Deep Convolutional Neural Network for Detecting Volcanic Thermal Anomalies from Satellite Images
## 2 Materials
### Data Source  
In this study, the Sentinel-2 and Landsat 8 satellite images were used to identify volcanic thermal anomalies. These two collections of data were chosen because they have a similar range of spectral bands in the portion of the spectrum from the visible to the infrared. Therefore, in this range they could be interchangeable, using the Sentinel-2 or \begin{table}
\begin{tabular}{c c} \hline \hline
**Volcano** & **Eruptive Activity between 2013 and 2022** \\ \hline Cumbre Vieja & 2021 \\ Etna & 2013–2014–2017–2018–2019–2020–2021–2022 \\ Pico do Fogo & 2014–2015 \\ Volcan de Fuego & 2017–2019–2020–2021 \\ Geldingadalir & 2020–2021 \\ Klauea & 2020–2021 \\ Klyuchevskaya & 2020–2021 \\ Pacaya & 2020–2021 \\ Stromboli & 2014–2019–2020–2021 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of volcanoes and years with eruptive activity between 2013 and 2022 sampled for the study. Details of volcanoes and associated links are available from the US National Museum of Natural History’s Global volcanism Program ([[https://volcano.si.edu/](https://volcano.si.edu/)]([https://volcano.si.edu/](https://volcano.si.edu/))). Figure 1: Volcano under analysis, (**a**) Cumbre Vieja (La Palma, Spain), (**b**) Etna (Italy), (**c**) Pico do Fogo (Cape Verde), (**d**) Volcan de Fuego (Guatemala), (**e**) Geldingadalir (Iceland), (**f**) Klauea (Hawaii, USA), (**g**) Klyuchevskaya (Kamchatka, Russia), (**h**) Pacaya (Guatemala), (**i**) Stromboli (Italy). All the images were downloaded from Google Earth Pro [[[http://www.earth.google.com](http://www.earth.google.com)]([http://www.earth.google.com](http://www.earth.google.com))]. Landsat 8 scenes based on the availability of the data for the specific situation, due to the passage of the satellite in a specific location and at a specific moment. The Sentinel-2 (S2) mission is part of the Copernicus programme of the European Space Agency (ESA). The mission comprises a constellation of two identical sun-synchronous satellites known as Sentinel-2A (S2A) and Sentinel-2B (S2B), which were launched in 2015 and 2017 respectively ([[https://sentinel.esa.int/web/sentinel/missions/sentinel-2/](https://sentinel.esa.int/web/sentinel/missions/sentinel-2/)]([https://sentinel.esa.int/web/sentinel/missions/sentinel-2/](https://sentinel.esa.int/web/sentinel/missions/sentinel-2/))). Each satellite in the constellation has a revisit time of 10 days, which collectively leads to a global revisit frequency of 5 days. Both satellites are equipped with a MultiSpectral Instrument (MSI) capable of capturing imagery in 13 bands. The spatial resolution of these bands vary, with a resolution of 10 m for the visible and near-infrared, 20 m for the red edge and shortwave infrared part of the spectrum, and 60 m for the atmospheric bands (\"Aerosol,\" \"Water vapor,\" and \"Cirrus\"). Landsat 8 (L8) is an Earth observation satellite launched in the frame of a joint mission between the United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) in 2013 ([[https://landsat.gsfc.nasa.gov/satellites/landsat-8/](https://landsat.gsfc.nasa.gov/satellites/landsat-8/)]([https://landsat.gsfc.nasa.gov/satellites/landsat-8/](https://landsat.gsfc.nasa.gov/satellites/landsat-8/))). It carries two sensors in a circular sun-synchronous orbit, namely Operational Land Imager (OLI) and Thermal InfraRed Sensor (TIRS). The first one (OLI) acquires 9 spectral bands, in the visible, near infrared and shortwave infrared (spatial resolution of 30 m). Moreover, it possesses a Panchromatic band at a spatial resolution of 15 m. The second sensor (TIRS) acquires data with 100 m spatial resolution for 2 thermal bands. Landsat 8 data have a high radiometric resolution (16 bits) and are characterized by a repeat cycle of 16 days. We have acquired all the images via the Google Earth Engine (GEE) platform ([[https://earthengine.google.com/](https://earthengine.google.com/)]([https://earthengine.google.com/](https://earthengine.google.com/))).