How satellites have revolutionized the study of volcanoes

Developments in satellite technology over the past decade have allowed the world to witness the devastating Hunga Tonga-Hunga Ha’apai eruption and its aftermath in real time and in unprecedented detail. The findings might shed light on the anatomy of rare explosive volcanic eruptions and their effects on the planet. But satellites are also helping volcanologists keep an eye on Earth’s more common (though less eye-catching) outbursts. 

The last time a volcano erupted as violently as Hunga Tonga-Hunga Ha’apai was 30 years ago. At that time, satellites monitoring Earth were few and far between. Those watching the planet’s surface were mostly run by the military. The European Space Agency (ESA), now an Earth-observing super-power, was only about to launch its first Earth-observing mission, the Remote-Sensing Satellite-1 (ERS-1). Cubesats that have since become a cornerstone of commercial Earth-observing constellations, such those of the U.S.-based company Planet, were yet to be invented.