This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Magma moving beneath a volcano can make the ground rise, sink or shift sideways. Measuring these changes gives scientists clues about where magma is stored and how it travels.
A study published in Geodesy and Geodynamics used satellite radar to examine the November 2025 eruption of Hayli Gubbi in Ethiopia's Afar Depression. Hayli Gubbi and nearby Erta Ale are separate volcanoes within the same volcanic zone, where three tectonic plates are pulling apart. The research is among the first to use the NASA–ISRO Synthetic Aperture Radar mission, or NISAR, to investigate an eruption.
Radar satellites send signals to the ground and record their return. Comparing measurements from different times can reveal movements as small as a few centimeters. However, a single satellite cannot show the full direction of movement.
To address this issue, the researchers combined NISAR's left-looking radar view with right-looking observations from Europe's Sentinel-1 satellites to reconstruct ground movement in three dimensions. Like photographs taken from different angles, the combined observations allowed the team to measure movement from east to west, north to south and up or down. "By viewing the volcanoes from complementary directions, we reconstructed the three-dimensional deformation field and measured all three components of ground movement at centimeter scale," said corresponding author Wenbin Xu of Central South University in China.
Although the eruption occurred at Hayli Gubbi, the strongest ground movement was detected at Erta Ale. Images showed two new collapse pits and cracks at Hayli Gubbi, while Erta Ale's summit crater partially collapsed. Radar data showed the ground at Erta Ale sinking and moving inward.
The researchers linked this pattern to two shallow dikes beneath Erta Ale. A dike is a steep crack that stores or transports magma. When magma drains from it, the surrounding rock may contract and the surface above may sink.
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