Wisdom-volkano : a novel tool based on open GIS and time-series to analyse and share volcanic data

Active volcanoes threaten life around. In order to predict their eruptions earlier and mitigate their hazards, several variables must be observed and compared. Geographical information systems (GIS) combine different geospatial images from remote or local sensing. However, GIS often miss how maps change during the time. In this thesis Wisdom-volkano is presented, a web GIS based on open source standards that integrates time-series on data such as seismic events and ground deformation from interferograms and global navigation satellite system (GNSS). Based on the data from stations and remote sensing on two different volcanos, the implemented tool allows maps visualization and trend analysis over time, to help detecting changes and eventually leading to volcanic activity alert ahead of eruptions. Integrating the time dimension increases greatly the utility of a GIS, not only for monitoring volcanoes and prevent eventual losses caused by them, but also for detecting land use changes and other purposes with a big economic impact.Active volcanoes threaten life of those living near them. Their eruptions can usually be predicted with some hours of anticipation, though not enough to mitigate their hazards. In order to get alerts earlier, several variables must be observed. A research on an African volcano eruption found that not one but six variables changed weeks (not hours) before. It is well worth studying it further: did it happen in other eruptions? Will it happen again? What about other volcanos? Scientists use tools called Geographical information systems (GIS) to show images over maps. Such images usually come from satellites, but also can be calculated from stations on the ground. However, GIS often miss one of the key variables: time. From a series of images of a same place during the time, one can extract how the points in the space changed along: they are time-series. In this thesis Wisdom-volkano is presented, a GIS based on a web site that integrates both image maps and time-series, developed with open source standards, with data from two African volcanos which are also some of the most active in the world. There were four main requirements: - Analysis of time-series. - Work online (as a web site to share data with other scientists) and offline (in a laptop when going to the volcanos). - Follow international standards, ensuring that the project can be used with others. - Allow plug in functionalities (like mathematically discarding outliers due to clouds or errors). The result is a tool that allows researchers to see maps and time-series of different types at the same time, like earthquakes or ground displacement (detail down to millimetres). Other variables like the sulphur in the air or the temperature will be added to Wisdom-volkano in the future. For the moment, researchers will be able to analyse only data about the past. Further development may define variable values limits, above which alerts could be triggered. When data is acquired and analysed in real time, these alerts may be done earlier, allowing people and assets to be prepared. Integrating the time dimension increases greatly the utility of a GIS, not only for monitoring volcanoes, but also for other purposes with a big economic impact