Cellphones can track people in disasters

Using data supplied by a mobile operator, Swedish researchers have shown that population movements after the 2010 Haiti earthquake followed regular patterns. The findings suggest movements of people after a disaster can be predicted beforehand, improving chances for aid to be delivered to the right places at the right time, scientists at Stockholm's Karolinska Institutet reported Tuesday. After the earthquake in Haiti, more than 600,000 people left the capital Port-au-Prince, and more than a million people were left homeless. Using mobile data provided by Digicel, the largest mobile operator in Haiti, the researchers looked for patterns in the movements of 2 million anonymous mobile users. "When disaster strikes we tend to seek comfort in our nearest and dearest," researcher Xin Lu said. "We can see by the mobile data that where people were over Christmas and New Year, which was just before the earthquake, tended to be the place where they returned to afterwards." Although people moved greater distances after the earthquake compared with before it, their daily movement patterns were extremely regular, the researchers found. It was possible to predict with 85 percent probability the location of people on a particular day in the three-month period following the earthquake, they said. Lu and fellow researcher Linus Bengtsson, doctoral students at the Karolinska Institutet's Division of Global Health, have created Flowminder.org, a non-profit organization with the aim of disseminating analyses of population movements for free to relief agencies after disasters.