A new study has revealed that Indonesia’s Anak Krakatau volcano, which collapsed in a devastating 2018 eruption and triggered a deadly tsunami, had been slipping for years showing warning signs that could have been detected in advance. Researchers at Penn State analyzed satellite data and found that the mountainside had been slowly shifting before its collapse, offering valuable insight into predicting similar disasters in the future.
Published in Geophysical Research Letters, the study used a technique called Interferometric Synthetic Aperture Radar (InSAR) to track surface deformation over a 12-year period. The analysis showed that the detachment fault beneath Anak Krakatau experienced approximately 15 meters (50 feet) of movement from 2006 to 2018, with notable acceleration just before the eruption. This data suggests that monitoring volcanic ground movement through satellites could provide crucial early warnings.
“Ocean volcanoes can collapse catastrophically and generate tsunamis, but in 2018, no one had instruments on the ground to detect the changes,” said Christelle Wauthier, associate professor of geosciences at Penn State. “Our study shows that, with remote sensing, we could have forecasted the collapse.”
The 2018 disaster struck without warning, killing over 400 people and injuring thousands on Java and Sumatra. The absence of ground-based monitoring at Anak Krakatau, due to safety and funding challenges, meant no one could track the acceleration of slip in real time. However, satellite techniques like InSAR, which detect minute surface movements, could offer a solution.
Lead author Young Cheol Kim, a doctoral candidate at Penn State, explained that analyzing such vast amounts of radar data required high-performance computing. “Integrating hundreds of satellite images demands significant computational power,” he said. The study relied on the Roar supercomputer at Penn State to process years of satellite data from ALOS-1, COSMO-SkyMED, and Sentinel-1.
The findings highlight the need for real-time satellite monitoring of active volcanoes worldwide. “If you see a sudden acceleration of slip, it might signal an imminent collapse,” Wauthier said. “Near-real-time InSAR processing could be a game-changer for monitoring volcanoes in remote or hazardous locations.”
With support from NASA, the U.S. National Science Foundation, and Germany’s Federal Ministry of Education and Research, this study underscores the potential of space-based technology in disaster prevention offering hope that future volcanic collapses might be predicted before tragedy strikes.