Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018

Authors

J. E. Hunt, National Oceanography Centre Southampton
D. R. Tappin, British Geological Survey
S. F.L. Watt, University of Birmingham
S. Susilohadi, Marine Geological Institute
A. Novellino, British Geological Survey
S. K. Ebmeier, University of Leeds
M. Cassidy, University of Oxford
S. L. Engwell, British Geological Survey
S. T. Grilli, University of Rhode Island
M. Hanif, Lembaga Ilmu Pengetahuan Indonesia
W. S. Priyanto, Lembaga Ilmu Pengetahuan Indonesia
M. A. Clare, National Oceanography Centre Southampton
M. Abdurrachman, Institut Teknologi Bandung
U. Udrekh, Badan Pengkajian dan Penerapan Teknologi

Document Type

Article

Date of Original Version

12-1-2021

Abstract

As demonstrated at Anak Krakatau on December 22nd, 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 km3) emplaced over 1.5 km into the adjacent basin. Our findings are consistent with en-masse lateral collapse with a volume ≥0.175 km3, resolving several ambiguities in previous reconstructions. Post-collapse eruptions produced an additional ~0.3 km3 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.

Publication Title, e.g., Journal

Nature Communications

Volume

12

Issue

1

Citation/Publisher Attribution

Hunt, J. E., D. R. Tappin, S. F. Watt, S. Susilohadi, A. Novellino, S. K. Ebmeier, M. Cassidy, S. L. Engwell, S. T. Grilli, M. Hanif, W. S. Priyanto, M. A. Clare, M. Abdurrachman, and U. Udrekh. "Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018." Nature Communications 12, 1 (2021). doi: 10.1038/s41467-021-22610-5.

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.