An earthquake of magnitude 7.3 (Richter scale) was recorded at 18.02 local time in the waters of Indonesia, off the island of Sulawesi, last Friday 28 September 2018.
According to data from the Italian Institute of Geophysics and Volcanology (Ingv) the earthquake had hypocentre at about 20 km of depth. The earthquake triggered a tsunami with six meters high waves that swept away houses in at least two cities, according to the authorities. The capital of the island, Palu, the city of Donggala and other coastal villages have been hit.
Thanks to Sentinel-2 it is possible to have a picture of large-scale destruction, emerging in and around the Indonesian city of Palu after the earthquake and tsunami. Two acquisitions have been taken into account. The first is an image of Palu city acquired by Sentinel-2B on 27 September 2018 before the disaster, whereas the second image has been captured by Sentinel-2A on 02 October 2018.
Below is an image comparison of Palu of these two acquisitions, before and after the earthquake. It is possible to identify in this way changes in the coastline. The third image of the animated gif shows instead the damage and loss assessment. In particular in green it is represented the coast that existed before the tsunami, whereas in violet the coast as it is now.