Map of population density of us 2015
With the pre-earthquake preparations that had been undertaken, the Flowminder team, together with Ncell, could quickly start analysing the mobile operator data. These data are crucial to understand where affected people are located, which is essential for effective humanitarian response operations. Lu pioneered the use of anonymous mobile operator data to assess population displacement after the Haiti earthquake and cholera outbreak. Very limited information is available to understand where affected people are located once these movements have begun. Similar patterns of large population movements occur in most major disasters. In the Kathmandu Valley, large numbers of people moved to sleep in open areas after losing their houses or due to fear of aftershocks.
Initially these occurred as people fled affected areas. In the earthquake aftermath, it was immediately apparent that there were mass movements of the population. It was the worst natural disaster to affect Nepal since the 1934 Nepal-Bihar earthquake. An estimated 500,000 buildings were destroyed or severely damaged and economic losses have been estimated at $7,065 million US dollars. After the initial earthquake, more than 300 aftershocks with a magnitude of 4.0 Mw1 or greater followed. The earthquake had a magnitude of 7.8 Mw1 and in total more than 9,000 people were killed, while 23,000 people were injured.
The devastating earthquake struck on 25th April at 11:56 NST, with the epicentre located in Gorkha District. With support from the Rockefeller Foundation, the project was initiated and rapid response capacity set up by the Flowminder team in Kathmandu, 1 week before the earthquake occurred. In light of this high potential risk, Flowminder and Ncell (the largest mobile operator in Nepal) agreed a collaboration in December 2014 to be able to respond to potential future earthquakes and to support long-term development objectives in Nepal. For many years Nepal has been one of the highest-risk countries in terms of the potential for a devastating earthquake.