19 Dec When disaster strikes: check your mobile (blog by Vincent Traag)

This Christmas it will be ten years ago that a huge tsunami struck the coasts of Indonesia, Malaysia, India and several other countries surrounding the Bengal Bay and the Indian Ocean. The huge waves reached up to thirty meters and were triggered by one of the largest earthquake ever. Its effects were felt as far away as the shores of Africa. Most of the 200 thousand casualties were concentrated in the Aceh province on the island of Sumatra, Indonesia, only a couple of dozen kilometres away from the epicentre. Preparations for remembering this tragedy are under way, and the provincial capital Banda Aceh will be the centre of the commemorations.

Unfortunately, such natural disasters are no exception to the region. Sumatra and Java lie at the fault line between the Eurasian and Indo-Australian tectonic plates, and earthquakes hit with some regularity, sometimes leading to tsunamis. But the region is also home to many volcanoes, with varying activity. Historically, some of the worst eruptions took place in Indonesia. About 70 thousand years ago the Toba eruption triggered a global cooling and is hypothesised to have lead to the near extinction of humanity. The eruption of Mount Tambora in 1815 caused some 100 thousand casualties. The last major eruption is already some time ago, but still people need to be regularly evacuated. A bit further up north, the Philippines are plagued by typhoons, with last year’s typhoon Haiyan being one of the most severe, killing over six thousand people. Recently, it was feared that history would repeat with the landfall of typhoon Hagupit. Although the storm left some victims in its wake, it did not bring about the devastation of last year’s typhoon.

The frustration of such natural disasters is that there is almost nothing we can do to prevent them. We can only do two things: try to warn people as early as possible, and to respond as best we can to the aftermath. Of course, it would be best if scientists could predict exactly when earthquakes, eruptions, tsunamis or typhoons will strike. But that is notoriously difficult, and the goal instead is to spot such disasters as soon as possible. Such early warning systems usually rely on closely monitoring physical sensors: seismometers to register earth’s movement, oceanic buoys to register sea levels, barometers to measure atmospheric pressure and so on. Such networks need a lot of maintenance and expertise, and it is difficult to cover an extensive area.

Increasingly, however, more people have mobile phones, and many of them have smartphones. The latest models are equipped with an impressive array of sensors such as an accelerometer, a magnetometer, an ambient light sensor, a barometer and of course GPS. All these sensors provide a trove of information, giving an unprecedented large sensor network. For example, researchers at Berkeley, California are developing a smartphone app called iShake to use the accelerometer to know if an earthquake occurred. It can also be used to provide a more extensive meteorological sensor network to provide maps of temperature, humidity and atmospheric pressure. In this way, smartphones help to warn people in time to seek help or shelter.

These same phones also play a critical role in the dissemintation of information. Governments can for example alert all mobile phones in a certain region of an imminent threat or danger. Of course they are also vital in searching your friends and family, and knowing if they are all right. Online services and social networks also try to do their share. Google launched a service they called Crisis Response, collaborating with partners to provide a source of information on a wide range of alerts and information in a crisis situation. Similarly, Facebook launched a Safety Check to let your friends and loved ones know you’re safe in case of an emergency situation.

But smartphones are not only useful before and during a disaster. They are also very useful in the aftermath. When typhoon Haiyan struck in the Philippines many people fled the area and more than four million people were displaced. Knowing where they went is essential for effective relief aid. Mobile phones provide a very simple way to estimate where people are. You don’t even need smartphones, because the location can be determined through the antennas used to service them (if they have not been destroyed in the disaster itself). When researchers looked at displacement after the 2010 earthquake in Haiti, they found that people mostly went to where they also went for Christmas and New Year, suggesting displaced people tend to go to close friends and relatives. This is vital information for relief workers, which enable them to target relief there where it is most needed. During such crisis times, the situation is often aggravated by the additional spreading of diseases. Again, it is essential to know where people are, and how they move across the country. Many diseases spread via close physical contact, as West Africa has witnessed with the outbreak of Ebola earlier this year. Without knowing where people move it is difficult to understand how the disease is likely to spread, and even more difficult to try to contain it.

So, mobile phones can contribute to our safety in many different ways. They can be used as sensors for early warning systems. Furthermore they provide a good way for disseminating information and warning people in time to prepare for the coming danger. Finally, they can be used to understand how the population is displaced and where to target relief efforts. Perhaps it would also be possible to use them in the case of man-made emergencies: terrorist attacks, riots or other large scale violence. How can we use mobile phones to keep people safe in such situations? And since such crises are created by people, perhaps we can also understand something of how they come about using mobile phones? In this way, mobile phones can perhaps help to make the world a bit safer.