The population at risk from sudden hazards, such as volcanic eruptions, is often estimated based on the location of the residents. Crisis management tools, such as evacuation and emergency plans, are usually based on this information. Therefore, they often do not reflect over- and underpopulation in areas where the present population is different from the resident population at the time of the crisis. In the context of data scarcity that characterises Goma city (North Kivu, DRC), the results of the spatial analysis presented in this paper allowed the population to be located hour by hour on each day of the week. The dual movement of those leaving and those arriving in Goma made it possible to establish the temporal variations of the total population located in Goma. The variations are similar on all weekdays but differ for Sundays. Moreover, the spatio-temporal location of the population over time appeared to be strongly influenced by the activity rhythm of the city's vital infrastructures. In other words, areas where commercial activities, employment, and schools are concentrated, are crowded during working hours, while areas with a predominantly residential character become depopulated at these times. Therefore, the various areas of Goma could be impacted differently by sudden natural hazards. If their occupancy is poorly known, the safety of the population and the satisfaction of their expectations are difficult to predict accurately. Modelling these spatio-temporal variations of the population is crucial information for quantifying the resources needed to manage a future sudden crisis in Goma.