Researchers from Institut Teknologi Sumatera, Institut Teknologi Bandung, and Indonesia's National Research and Innovation Agency used three years of satellite ground motion data to track how the Earth's crust is slowly deforming. The study was published in the journal Geodesy and Geodynamics .
"Central Sumatra sits on a highly active plate boundary," explains corresponding author Irwan Meilano. "The Indo-Australian Plate is slowly diving beneath the Sundaland Plate. As these two plates grind against each other, certain sections become locked. Instead of sliding smoothly, they get stuck, causing strain to build up over decades or centuries until it is suddenly released as an earthquake."
Using data from 35 continuous GNSS stations collected between 2018 and mid-2021, the team found that deformation across the region is dominated by crustal compression, with the most intense strain concentrated in two areas: near Siberut Island in the Mentawai Islands, and along sections of the Sumatran Fault Zone on the mainland.
"We deduced that large earthquakes in this region tend to repeat roughly every 200 years," says Meilano. "Since the last great earthquake struck in 1833 (a magnitude of 8.8), about 200 years of tectonic strain has built up."
Based on this assumption, the researchers studied two segments of the undersea fault to assess the potential for a future major earthquake:
The researchers also examined the Sianok segment of the Sumatran Fault Zone , a major crack that runs the length of Sumatra. "GNSS measurements indicate that the fault is slipping at a rate of around 16.5 mm per year and remains locked to a depth of about 15 km," shares Meilano. "This suggests strain is continuing to build within the fault system on land as well."
Overall, the study provides a detailed map of where Central Sumatra is currently deforming. "By pinpointing the areas of greatest strain accumulation, the study offers critical information for updating seismic hazard assessments and long-term disaster planning," adds Meilano.
While the team could not predict exactly when an earthquake will happen, their findings nonetheless show that substantial energy continues to build beneath parts of Central Sumatra.
"With these results, we can confirm that Central Sumatra will face massive earthquakes and requires long-term urban planning, structural engineering adjustments, and community emergency preparedness along both the coastlines and the mainland," notes Meilano.
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Contact the author:
Irwan Meilano
Faculty of Earth Sciences and Technology, Institute of Technology Bandung (ITB), Bandung, Indonesia
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Geodesy and Geodynamics
Data/statistical analysis
Not applicable
Present-day crustal deformation in central Sumatra, Indonesia derived from GNSS observation and tectonic implications
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Ongky Anggara reports a relationship with Sumatra Institute of Technology that includes: employment. Lecturer If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.