Some years ago, it was found that earthquakes can generate pressure waves in one of the atmospheric layers - the ionosphere - which in turn can affect Global Positioning System (GPS) signals. Since atmospheric signals travel much faster than tsunamis, they constitute a potential means to warn countries of upcoming tsunamis. With her ERC Starting grant, Dr Elvira Astafyeva at the Institut de Physique du Globe de Paris (France) studies the ionosphere’s response to large earthquakes by continuous GPS monitoring of the upper atmosphere. The outcome of her innovative research would contribute to determine parameters of seismic source from ionospheric data shortly after an earthquake. This would open new possibilities of early tsunami warnings.