Current-day volcanic activity in the Azores archipelago is characterized by seismic events and secondary manifestations of volcanism. Remote sensing techniques have been widely employed to monitor deformation in volcanic systems, map lava flows, or detect high-temperature gas emissions. However, using satellite imagery, it is still challenging to identify low-magnitude thermal changes in a volcanic system. In 2010, after drilling a well for geothermal exploration on the northern flank of Fogo Volcano on São Miguel Island, a new degassing and thermal area emerged with maximum temperatures of 100 °C. In the present paper, using the ASTER sensor, we observed changes in the near-infrared signals (15 m spatial resolution) six months after the anomaly emerged. In contrast, the thermal signal (90 m spatial resolution) only changed its threshold value one and a half years after the anomaly was recognized. The results show that wavelength and spatial resolution can influence the response time in detecting changes in a system. This paper reiterates the importance of using thermal imaging and high spatial resolution images to monitor and map thermal anomalies in hydrothermal systems such as those found in the Azores.

<p>Insular ecosystems are natural laboratories in which evolution processes may be isolated and examined before being connected and expanded to the more complicated patterns displayed by more extensive systems. Similarly, islands can provide insights into effective land/costal management techniques. In the current climate change context, and with most of these territories being highly vulnerable to natural hazards (e.g., landslides, volcanic eruptions, earthquakes, etc.), it is critical to detect and monitor relevant land surface, and land use/land cover (LULC) changes as soon as they occur, to identify and address their drivers and triggers through effective land/coastal planning and management policies. This research aims to evaluate the current state-of-the-art in remote sensing-based multi-sensor land surface and LULC change detection in terms data availability/complementarity, methodological approaches, data processing strategies, and parameters. A systematic literature review was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses declaration (PRISMA) as a guideline to reach this goal. A search was run by applying nine combinations of relevant keywords and Boolean operators to the title, abstract, and keywords of pre-selected works. Review papers, conference papers, publications authored in languages other than English and  those that were not open access were not included. The search period was between January 2010 and June 2022 (the last access was done on 30 June 2022). As a result, a database including  167 journal articles from the Web of Science was created. The main results revealed an increasing number of published papers using remote sensing to map and quantify LULC change areas. Multispectral data were the most relevant source for identifying and analyzing surface changes (e.g., Landsat mission). The results revealed also that the highest number of studies was published in 2020 and 2021. The continent with more case studies was Asia, with China being the more productive country in this field. Most articles (26%) analyzed in this study were published in the Remote Sensing journal (MDPI). Moreover, this analysis showed that the combination of different parameters studied in this paper, namely the data source, data type, sensors, approaches, algorithms, software, platforms, spatial resolution and temporal resolution, might foster new opportunities for improved remote sensing-based LULC monitoring in oceanic islands and coastal areas.</p>