Ground Deformation of Anak Krakatau Volcano Before and After the December 2018 Eruptions Observed by SAR Images

Abstract

On December 22nd, 2018, the area around Sunda Strait was hit by a tsunami which had been associated by most scientists to the eruption of Mount Anak Krakatau. An image from Sentinel-1 satellite captured on December 23rd, 2018 western Indonesia time clearly showed that Mount Anak Krakatau had changed in shape. This article describes the use of Synthetic Aperture Radar (SAR) data that have been observed by Sentinel-1 satellite at 12-day temporal resolution to identify morphological changes of this volcano. In addition, interferometry method was used to identify ground deformation before and after the December 22nd eruption. The study collected and processed SAR data in ground range multi look detected (GRD) and slant range single look complex (SLC) products from June 2018 to May 2019. The result showed that Mount Anak Krakatau’s active period started in early December 2018 and could be classified into destructive and constructive phases. Based on Sentinel-1 image, the destructive phase was identified from December 23rd, 2018 to December 31st, 2018 while the constructive phase was identified from January 3rd, 2019 onward. Line of sight displacement derived from the interferogram indicated ground deformation before the active period and during constructive phase.