From gradual spreading to catastrophic collapse – Reconstruction of the 1888 Ritter Island volcanic sector collapse from high-resolution 3D seismic data

Research output: Contribution to journalArticle

Authors

  • Jens Karstens
  • Christian Berndt
  • Morelia Urlaub
  • Aaron Micallef
  • Melanie Ray
  • Ingo Klaucke
  • Sina Muff
  • Dirk Klaeschen
  • Michel Kühn
  • Theresa Roth
  • Christoph Böttner
  • Bettina Schramm
  • Judith Elger
  • Sascha Brune

Colleges, School and Institutes

External organisations

  • GEOMAR - Helmholtz Zentrum für Ozeanforschung Kiel
  • University of Malta
  • University College London
  • Climate Dynamics and Landscape Evolution, GFZ German Centre for GeoSciences

Abstract

Volcanic island flank collapses have the potential to trigger devastating tsunamis threatening coastal communities and infrastructure. The 1888 sector collapse of Ritter Island, Papua New Guinea (in the following called Ritter) is the most voluminous volcanic island flank collapse in historic times. The associated tsunami had run-up heights of more than 20 m on the neighboring islands and reached settlements 600 km away from its source. This event provides an opportunity to advance our understanding of volcanic landslide-tsunami hazards. Here, we present a detailed reconstruction of the 1888 Ritter sector collapse based on high-resolution 2D and 3D seismic and bathymetric data covering the failed volcanic edifice and the associated mass-movement deposits. The 3D seismic data reveal that the catastrophic collapse of Ritter occurred in two phases: (1) Ritter was first affected by deep-seated, gradual spreading over a long time period, which is manifest in pronounced compressional deformation within the volcanic edifice and the adjacent seafloor sediments. A scoria cone at the foot of Ritter acted as a buttress, influencing the displacement and deformation of the western flank of the volcano and causing shearing within the volcanic edifice. (2) During the final, catastrophic phase of the collapse, about 2.4 km 3 of Ritter disintegrated almost entirely and traveled as a highly energetic mass flow, which incised the underlying sediment. The irregular topography west of Ritter is a product of both compressional deformation and erosion. A crater-like depression underlying the recent volcanic cone and eyewitness accounts suggest that an explosion may have accompanied the catastrophic collapse. Our findings demonstrate that volcanic sector collapses may transform from slow gravitational deformation to catastrophic collapse. Understanding the processes involved in such a transformation is crucial for assessing the hazard potential of other volcanoes with slowly deforming flanks such as Mt. Etna or Kilauea.

Details

Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalEarth and Planetary Science Letters
Volume517
Early online date23 Apr 2019
Publication statusPublished - 1 Jul 2019

Keywords

  • 3D seismic interpretation, landslide, Ritter Island, tsunami, volcanic sector collapse