Submarine terraced deposits linked to periodic collapse of caldera-forming eruption columns
Gilchrist, J.T.; Jellinek, A.M.; Hooft, E.E.E.; Wanket, S. (2023). Submarine terraced deposits linked to periodic collapse of caldera-forming eruption columns. Nature Geoscience 16(5): 446-453. https://dx.doi.org/10.1038/s41561-023-01160-z
In: Nature Geoscience. Nature Publishing Group: London. ISSN 1752-0894; e-ISSN 1752-0908, meer
|  |
| Auteurs | | Top |
- Gilchrist, J.T.
- Jellinek, A.M.
- Hooft, E.E.E.
- Wanket, S.
|
|
|
| Abstract |
Catastrophic, caldera-forming explosive eruptions generate hazardous ash fall, pyroclastic density currents and, in some cases, tsunamis, yet their dynamics are still poorly understood. Here we use scaled analogue experiments and spectral analysis of well-preserved concentric terracing of seafloor deposits built by submarine caldera-forming explosive eruptions to provide insights into the dynamics governing these eruptions and the resultant hazards. We show that powerful submarine eruption columns in collapsing regimes deliver material to the sea surface and seabed in periodic annular sedimentation waves. Depending on the period between successive waves, which becomes shorter with decreasing jet strength, their impact and spread at the sea surface and/or seabed can excite tsunamis, drive radial pyroclastic density currents and build concentric terraces with a wavelength that decreases with distance, or deposits that thin monotonically. Whereas the Sumisu (Izu–Bonin arc) caldera deposit architecture is explained by either a subaerial or deep-water model involving no interaction between sedimentation waves and the sea surface, those of the Macauley (Kermadec arc) and Santorini (Hellenic arc) calderas are consistent with a shallow-water model with extensive sedimentation wave–sea surface–seabed interactions. Our findings enable an explicit classification of submarine caldera-forming explosive eruption dynamics and quantitative estimates of eruption rates from their terraced deposits. |
|
