Characterizing spatiotemporal ground deformation at Whakaari (White Island) volcano, New Zealand, using InSAR time-series analysis

Whakaari (White Island) volcano is the most active volcano in New Zealand and has caused some of the deadliest volcanic eruptions in the country’s history. The volcano has a dynamic hydrothermal system and has had 4 eruptive periods since 2016 with the most recent period still ongoing. In this study, we aim to understand the pre-and post-eruption deformation processes occurring at Whakaari using interferometric synthetic aperture radar (InSAR). We analyze Sentinel-1 Bursts spanning the period 2014 to 2024 from 3 different tracks (1 ascending and 2 descending) using small baseline subset (SBAS) InSAR time-series analysis. Three stacks are analyzed spanning the periods (a) 2014 to 2024, (b) 6 months before and after the 2016 eruptions, and (c) 6 months before and after the 2019 eruption. Initial results show several phases of uplift and subsidence spanning the entire period. These phases of observed vertical displacement also vary spatially among the western, central, and eastern sub-craters. These results will be discussed in the context of the long-term deformation rates at Whakaari over the last decade as well as short-term pre- and post-eruptive processes focused on the 2016 and 2019 eruptions. Results will help understand precursory deformation processes at active volcanoes and the use of InSAR as a potential monitoring tool.