To predict when a volcano will erupt, researchers rely on indirect signals. However, without long-term and ground-based observations, it is difficult to determine whether these signals are normal disturbances or indicators of a looming eruption. New research suggests satellite data could help to fill that gap and improve scientists understanding of the complex warning signs a volcano may issue before it erupts.
The multidecadal study analyzed 17 years of remote sensing observations of 47 volcanoes in Latin America, where more than 60 per cent of active volcanoes are unmonitored. The researchers looked at three types of data: sulfur dioxide gas emissions, which often increase before a volcano erupts; thermal measurements and radar data that show how a volcano is changing shape.
On the basis of their analysis of the satellite data, the team found that the majority of the 47 volcanoes were on a spectrum between open systems, able to release gas and pressure and closed systems, which are likely building up internal pressure.
In addition, an in-depth study of the Copahue volcano on the Chile-Argentina border showed that its eruptions are preceded by a regular cycle of ash plumes, gas venting and increased thermal activity and internal pressure, all of which can be effectively tracked from space.
The research also shows that this kind of observations can have weaknesses that prevent satellites from being an accurate predictive tool. For example, despite NASA collecting data on sulfur dioxide emissions over the Colima volcano in Mexico, the volcanic emissions are often masked by pollution from Mexico City. It is important that different types of satellite data are used together and in combination with ground measurements, in order to provide valuable information on normal cycles of volcanic behavior.
Examining the long-term behavior of volcanoes with satellite data is an important step toward a better understanding of the scientific tools available to predict eruptions.