# An Overview of Infrared Remote Sensing of Volcanic Activity
## 2 Infrared Remote Sensing: Theory
More recently, [11] used satellite-retrieved TIR observations, augmented with ground-based observations, to isolate precursory signals, and a subsequent eruption, at Redoubt Volcano in Alaska and [12] demonstrated the utility of satellite TIR observations for determining lava extrusion rates and discriminating different types of lava dome activity, at Merapi Volcano, Indonesia. Likewise, several satellite sensors have MIR detection capabilities, which have been shown to be useful in monitoring both thermally-anomalous volcanic surfaces and, also, those at a more ambient temperature. [PERSON] and [PERSON] [13; 14], for example, utilised MIR bands to quantify the radiant emissions from a number of volcanoes and used the same data \begin{table}
\begin{tabular}{l l} \hline \hline
**Sensor** & **Characteristics** \\ \hline
**Advanced Along-Track Scanning Radiometer (AATSR)** on-board the & 7 bands: VNIR-MIR-TIR \\ European Space Agency (ESA) Envisat satellite & Resolution: 1000 m \\ \hline
**Advanced Land Imager (ALD)** on-board the NASA Earth Observation & 9 bands: VNIR-SWIR \\ (EO)-1 satellite & Resolution: 30 m \\ \hline
**Advanced Spaceborne Thermal Emission and Reflection Radiometer** & 14 bands: VNIR-SWIR-TIR \\ (**ASTER)** on-board NASA Terra & Resolution: 15, 30 and 90 m \\ \hline
**Along Track Scanning Radiometer (ATSR)-1** and **ATSR-2** on-board & 4 bands: SWIR-MIR-TIR \\ the ESA European Remote Sensing (ERS) Satellites & Resolution: 1000 m \\ \hline
**Advanced Very High Resolution Radiometer (AVHRR)** on-board the & 5 bands: VNIR-SWIR-MIR-TIR \\ National Oceanic and Atmospheric Administration (NOAA) satellites & Resolution: 1100 m \\ \hline
**Enhanced Thematic Mapper Plus (ETM+)** on-board the NASA & 8 bands: VNIR-SWIR-TIR \\ Landsat 7 satellite & Resolution: 15, 30 and 60 m \\ \hline
**Imager** on-board the NASA Geostationary Operational Environmental Satellite (GOES) & 5 bands: VNIR-MIR-TIR \\
**Hyperion** on-board the NASA EO-1 satellite & 220 bands: VNIR-SWIR \\  & Resolution: 30 m \\ \hline
**Meteosat Visible and InfraRed Imager (MVIRI)** on-board the ESA & 3 bands: VIS-TIR \\ Meteosat First Generation satellites & Resolutions: 250-5000 m \\ \hline
**Moderate-resolution Imaging Spectroradiometer (MODIS)** on-board & 32 bands: VNIR-MIR-TIR \\ NASA Terra and Aqua satellites & Resolutions: 250, 500 and 1000 m \\ \hline
**Operational Land Imager (OLI)** on-board the NASA Landsat-8 satellite &
\begin{tabular}{l} 9 bands: VNIR-SWIR \\ Resolutions: 15-30 m \\ \end{tabular} \\ \hline
**OPtical Sensor (OPS)** on-board the Japanese Earth Resources Satellite 1 & 7 bands: VNIR-SWIR \\ (JERS-1) satellite & Resolution: 18 m \(\times\) 24 m \\ \hline
**Spinning Enhanced Visible \& Infrared Imager (SEVERI)** on-board & 12 bands: VNIR-TIR \\ the ESA Meteosat Second Generation satellites & Resolution: 1000–3000 m \\ \hline
**Thermal Infrared Sensor (TIRS)** on-board the NASA & 2 bands: TIR \\ Landsat-8 satellite & Resolution: 100 m \\ \hline
**Visible Infrared Imaging Radiometer Suite (VIIRS)** on board the & 22 bands: VNIR-SWIR-TIR \\ NASA Suomi National Polar-Orbiting Partnership (S-NPP) satellite & Resolutions: 375-750 m \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics and attributes of the main sensors used for the infrared remote sensing of volcanoes, with abbreviations used in this paper also defined. to monitor the variability in heat flux from the lava lake at Mount Erbus in Antarctica, respectively, while [15] demonstrated a volcanic activity detection system that harnesses detected MIR signals. Some satellite sensors have been equipped with SWIR detection capabilities, in large part because SWIR image data can be used in land surface reflectance studies [16]; in fact, the SWIR bands on ASTER were chosen for the absorption features of various minerals and clays [17; 18]. However, such bands are also useful in monitoring hot surfaces, especially at night [19], and until the malfunction in 2008, ASTER was regularly used for such purposes.