Multi-Temporal InSAR Analysis for Monitoring the Ground Deformation of Mount Sinabung

Deformation of a volcano’s surface is a geohazard caused by volcanic activities and seismicity. Monitoring the
deformations serves as a part of an early warning system that can mitigate disasters. Between 2017-2022, Mount
Sinabung volcano’s ground deformation was monitored and analyzed using Multi-Temporal Interferometry
Synthetic Aperture Radar (InSAR) and spatial statistics. The results showed substantial changes in surface
elevation. The maximum monthly inflation was 4.7 cm in 2020, while the maximum monthly deflation was -4.7
cm in 2018. The correlation between the number of monthly eruptions and deformation patterns was very weak
at 0.09 to -0.09, which indicated that the volcano’s eruptions did not lead to ground deformation around Mount
Sinabung and vice versa. Moreover, the ground deformation at Mount Sinabung did not indicate a consistent or
periodic pattern. Some areas experienced higher deformation rates than others, depending on the land cover and
underground magmatic activities. The volcano surface has been inflating over the past six years with an average
rate of 0.14 cm/year. Data from sample observation points recorded the highest rate of 1.74 cm/year at the midslope,
and the lowest rate of 0.62 cm/year at the foot of the mountain. The mountain caldera showed a ground
surface inflation rate of 1.53 cm/year. The data showed that, despite the absence of an explosive or magmatic
eruption since Mount Sinabung returned to activity, its caldera and surface continue to undergo deformations at
higher velocities. Future explosive eruptions are expected, and preemptive preparations for potential disasters
should be planned.