On the 28th of September, a series of earthquakes struck central Sulawesi province, the strongest a 7.4 magnitude earthquake with an epicentre only 10 kilometres deep. The earthquake triggered a tsunami that hit the provincial capital Palu and the coastal city of Donggala with waves up to six meters high. The earthquake, tsunami, aftershocks and resulting liquefaction and landslides caused significant damage, loss of life and challenges for the delivery of aid in the worst affected areas.

Since the onset of the disaster, IMPACT, through its humanitarian data initiative REACH, supported the Government of Indonesia and the PP Cluster by assessing the scale of the damage through remote sensing. With the aid of satellite images, the collaboration resulted in a series of maps identifying, for example, damaged buildings, displacement sites and locations of liquefaction and landslides. The rapid deployment soon developed to a humanitarian needs and shelter assessment of disaster-affected areas.