Since 14 January, the Tungurahua volcano in Ecuador has seen a continuous build-up in seismic and eruptive activity. Located 140 km south of the capital city Quito, the volcano rises to 5,023 m and becomes active every 100 years or so. Eruptions are taking place at the summit crater, generating loud explosions, pumice clouds and lava flows. Volcanologists are expecting a violent eruptive climax soon and have alerted the Ecuadorian authorities to evacuate the population in the volcano’s vicinity.

Authorities and international relief teams need a rapid mapping tool to identify urban areas and settlements, and to define evacuation plans according to different levels of eruptive intensity.

A SPOT 5 image acquired 20 January 2005 was delivered at the request of the members of the International Charter on Space and Major Disasters. This archive image is the foundation for the required mapping tool and will serve as a baseline to assess the impacts of the eruption.

The mapping tool was produced in two stages: first, urban areas and settlements were identified; second, different evacuation zones were traced around the volcano according to levels of eruptive intensity.

Urban areas are easily identified in band 1 of the SPOT 5 multispectral image. Features in the image are classified according to brightness to highlight buildings, which are then coloured and draped over the initial image.