Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33990552.
- Also identified by DOI 10.1038/s41467-021-22610-5 and PMC identifier 8121911.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
As demonstrated at Anak Krakatau on December 22<sup>nd</sup>, 2018, tsunamis generated by volcanic flank collapse are incompletely understood and can be devastating. Here, we present the first high-resolution characterisation of both subaerial and submarine components of the collapse. Combined Synthetic Aperture Radar data and aerial photographs reveal an extensive subaerial failure that bounds pre-event deformation and volcanic products. To the southwest of the volcano, bathymetric and seismic reflection data reveal a blocky landslide deposit (0.214 ± 0.036 km<sup>3</sup>) emplaced over 1.5 km into the adjacent basin. Our findings are consistent with en-masse lateral collapse with a volume ≥0.175 km<sup>3</sup>, resolving several ambiguities in previous reconstructions. Post-collapse eruptions produced an additional ~0.3 km<sup>3</sup> of tephra, burying the scar and landslide deposit. The event provides a model for lateral collapse scenarios at other arc-volcanic islands showing that rapid island growth can lead to large-scale failure and that even faster rebuilding can obscure pre-existing collapse.