Processed Sentinel-1 InSAR data of the multi-year gradual flank destabilisation of Anak Krakatau volcano, Indonesia

The Dec 22nd 2018 flank collapse and tsunami at Anak Krakatau in Indonesia is a key event in geosciences as little is known about the lead-up processes and deformation changes prior to flank failure. We processed Sentinel-1 satellite radar data in both ascending (orbit 171) and descending (orbit 47) acquisition using multi-temporal InSAR with the Small BAseline (SB) method during the 4 years prior to the collapse. The data shows that the flank was already moving for years prior to collapse, demonstrating that developing instability in volcano can be monitored long before a collapse. The southwest flank movement rates averaged approx. 27 cm/yr, but underwent intermittent accelerations coinciding with distinct intrusion events in Jan/Feb 2017 and in Jun 2018. The data archived here supplements the material detailed in Zorn et al. (202X, https://doi.org/XXXXX).