TY - JOUR
T1 - From gradual spreading to catastrophic collapse – Reconstruction of the 1888 Ritter Island volcanic sector collapse from high-resolution 3D seismic data
AU - Karstens, Jens
AU - Berndt, Christian
AU - Urlaub, Morelia
AU - Watt, Sebastian F.L.
AU - Micallef, Aaron
AU - Ray, Melanie
AU - Klaucke, Ingo
AU - Muff, Sina
AU - Klaeschen, Dirk
AU - Kühn, Michel
AU - Roth, Theresa
AU - Böttner, Christoph
AU - Schramm, Bettina
AU - Elger, Judith
AU - Brune, Sascha
PY - 2019/7/1
Y1 - 2019/7/1
N2 - 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.
AB - 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.
KW - 3D seismic interpretation
KW - landslide
KW - Ritter Island
KW - tsunami
KW - volcanic sector collapse
UR - http://www.scopus.com/inward/record.url?scp=85064519856&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2019.04.009
DO - 10.1016/j.epsl.2019.04.009
M3 - Article
AN - SCOPUS:85064519856
SN - 0012-821X
VL - 517
SP - 1
EP - 13
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -