Volcanic eruptions and slope failures have the potential to trigger destructive tsunamis as recently demonstrated by the 2022 eruption of Hunga Tonga-Hunga Ha’apai and the 2018 sector collapse of Anak Krakatau. The most devastating volcanic tsunami event in historic times was the eruption of Krakatau in 1883, which caused more than 36.000 fatalities. To date, there are no effective early-warning systems for volcanic tsunamis as the underlying processes are still not fully understood. During the proposed ship time, we will survey the deposits of the 2018 sector collapse as well as the 1883 pyroclastic flow deposits using 2D seismic profiles. In addition, we will obtain sediment cores and complement to marine studies by remote sensing data. Based on the expected dataset, we will constrain the most important tsunami source parameters for both events, which will be evaluated using numerical tsunami simulations. This will significantly improve the volcanogenic tsunami hazard assessment for the Sunda Strait and for this type of events in general.