Sedimentology of Volcanic Debris Avalanche Deposits

Dufresne, Anja; Zernack, Anke; Kontny, Bernard; Thouret, Jean‐Claude; Roverato, Matteo

doi:10.1007/978-3-030-57411-6_8

Cited by 17 publications

(13 citation statements)

References 151 publications

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“…several studies applied tephrochronology and radiocarbon dating to soil layers above and below a debris avalanche (Zernack et al, 2011;Fujine et al, 2016;Goto et al, 2019). However, a debris avalanche often erodes the ground surface during its flow (Ui et al, 2000;van Wyk de Vries et al, 2001;Yoshida and Sugai, 2007;Dufresne et al, 2021). Thus, the underlying soil does not necessarily represent the time immediately before a sector collapses.…”

Section: Figurementioning

confidence: 99%

“…The Kaminagawa Formation often intrudes into the Tpfl deposit and occurs as a lens (Figures 5C,D). These complex hummock structures were attributed to the non-welded nature of the Tpfl deposit (Goto et al, 2019) and suggest that the Tpfl deposit was mixed with other blocks and fragmented during the transport and emplacement of the ZDA (Dufresne et al, 2021;Paguican et al, 2021).…”

Section: Lithofacies Of the Zenkoji Debris Avalanche Depositmentioning

confidence: 99%

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Re-investigation of the sector collapse timing of Usu volcano, Japan, inferred from reworked ash deposits caused by debris avalanche

Nakagawa

Matsumoto²,

Yoshizawa³

2022

Front. Earth Sci.

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It is essential to establish the timing of past sector collapse events at a volcanic edifice to evaluate not only the evolution of the volcanic system but also potential volcanic hazards. This can be done by determining the age of the collapse-generated debris avalanche deposits. However, without evidence of an associated magmatic eruption, it is impossible to recognize juvenile materials in these deposits. Thus, it is usually difficult to determine the precise age of sector collapse. Usu is a post-caldera volcano of the Toya Caldera (Hokkaido, Japan) and has been constructed since ca. 19–18 ka on top of the caldera-forming Toya pyroclastic flow deposits (Tpfl deposit: 106 ka). A sector collapse occurred after the formation of a stratovolcano edifice and produced the Zenkoji debris avalanche (ZDA) deposit with reported ages ranging from >20 to 6 ka. We investigated the tephrostratigraphy preserved in the soil above the ZDA deposit and in the surrounding area and recognized fine ash fall deposits at two locations, above and east of the ZDA deposit. The glass shards within these deposits were correlated with several tephra layers with the majority being derived from Tpfl deposits. Thus, these ash deposits should be considered reworked tephra. A considerable number of hummocks in the ZDA deposit were also composed of deformed and fragmented Tpfl deposits, which suggests that the ZDA bulldozed and partially incorporated the Tpfl deposit on the flank of the volcano. Deformation and fragmentation of the non-welded soft silicic Tpfl deposit during the transport and emplacement of the ZDA produced an accompanying ash cloud, which deposited the observed glassy, fine, ash fall units. Radiocarbon dating of soil samples directly below and above the reworked ash deposits allowed dating the sector collapse to ca. 8 ka. This age is much younger than previously proposed results. Based on our findings, the transport and emplacement mechanism of the sector collapse should be revised. Our study shows that reworked ash layers caused by the flow of a debris avalanche can be used as an indicator of the timing of a sector collapse of the volcano.

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Section: Figurementioning

confidence: 99%

Section: Lithofacies Of the Zenkoji Debris Avalanche Depositmentioning

confidence: 99%

Re-investigation of the sector collapse timing of Usu volcano, Japan, inferred from reworked ash deposits caused by debris avalanche

Nakagawa

Matsumoto²,

Yoshizawa³

2022

Front. Earth Sci.

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“…They correspond to chaotic breccias, with extremely variable grain size (size from a few micrometers to blocks >10 m), and a main sandy grain size, without internal structures (Figure 6A; Leyrit, 2000). Blocks (blocks are 1-100 m size; megablocks are >100 m size; Figure 10A) and clasts (clasts are 2 mm-1 m size; megaclasts are >1 m) use to show jigsaw cracks (Figure 10B) and the matrix (1 µm-2 mm size) forms mixed facies when combined with clasts (Figure 10C), or matrix facies if it represents the dominant fraction in the deposit (Dufresne et al, 2021). The surface of the deposit is usually hummocky (Figure 10D; Ui, 1983;Bernard et al, 2021;Dufresne et al, 2021).…”

Section: Characteristics Of Debris Avalanche Depositsmentioning

confidence: 99%

“…Blocks (blocks are 1-100 m size; megablocks are >100 m size; Figure 10A) and clasts (clasts are 2 mm-1 m size; megaclasts are >1 m) use to show jigsaw cracks (Figure 10B) and the matrix (1 µm-2 mm size) forms mixed facies when combined with clasts (Figure 10C), or matrix facies if it represents the dominant fraction in the deposit (Dufresne et al, 2021). The surface of the deposit is usually hummocky (Figure 10D; Ui, 1983;Bernard et al, 2021;Dufresne et al, 2021). VDADs are described in terms of their characteristic facies (Ui, 1983;Glicken, 1991Glicken, , 1996Palmer et al, 1991;Capra et al, 2002;Scott et al, 2001;Roverato et al, 2011;van Wyk de Vries and Davies, 2015;Dufresne et al, 2021).…”

Section: Characteristics Of Debris Avalanche Depositsmentioning

confidence: 99%

“…The surface of the deposit is usually hummocky (Figure 10D; Ui, 1983;Bernard et al, 2021;Dufresne et al, 2021). VDADs are described in terms of their characteristic facies (Ui, 1983;Glicken, 1991Glicken, , 1996Palmer et al, 1991;Capra et al, 2002;Scott et al, 2001;Roverato et al, 2011;van Wyk de Vries and Davies, 2015;Dufresne et al, 2021). The mobility of VDADs can be expressed as H/L ratio (height loss v/s run out distance, i.e., coefficient of friction).…”

Section: Characteristics Of Debris Avalanche Depositsmentioning

confidence: 99%

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Volcanic Lateral Collapse Processes in Mafic Arc Edifices: A Review of Their Driving Processes, Types and Consequences

et al. 2021

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Volcanic cones are frequently near their gravitational stability limit, which can lead to lateral collapse of the edifice, causing extensive environmental impact, property damage, and loss of life. Here, we examine lateral collapses in mafic arc volcanoes, which are relatively structurally simple edifices dominated by a narrow compositional range from basalts to basaltic andesites. This still encompasses a broad range of volcano dimensions, but the magma types erupted in these systems represent the most abundant type of volcanism on Earth and rocky planets. Their often high magma output rates can result in rapid construction of gravitationally unstable edifices susceptible both to small landslides but also to much larger-scale catastrophic lateral collapses. Although recent studies of basaltic shield volcanoes provide insights on the largest subaerial lateral collapses on Earth, the occurrence of lateral collapses in mafic arc volcanoes lacks a systematic description, and the features that make such structures susceptible to failure has not been treated in depth. In this review, we address whether distinct characteristics lead to the failure of mafic arc volcanoes, or whether their propensity to collapse is no different to failures in volcanoes dominated by intermediate (i.e., andesitic-dacitic) or silicic (i.e., rhyolitic) compositions? We provide a general overview on the stability of mafic arc edifices, their potential for lateral collapse, and the overall impact of large-scale sector collapse processes on the development of mafic magmatic systems, eruptive style and the surrounding landscape. Both historical accounts and geological evidence provide convincing proofs of recurrent (and even repetitive) large-scale (>0.5 km3) lateral failure of mafic arc volcanoes. The main factors contributing to edifice instability in these volcanoes are: (1) frequent sheet-like intrusions accompanied by intense deformation and seismicity; (2) shallow hydrothermal systems weakening basaltic rocks and reducing their overall strength; (3) large edifices with slopes near the critical angle; (4) distribution along fault systems, especially in transtensional settings, and; (5) susceptibility to other external forces such as climate change. These factors are not exclusive of mafic volcanoes, but probably enhanced by the rapid building of such edifices.

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Volcanic Debris Avalanches: Introduction and Book Structure

Roverato

Dufresne

2020

Volcanic Debris Avalanches

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Sedimentology of Volcanic Debris Avalanche Deposits

Cited by 17 publications

References 151 publications

Re-investigation of the sector collapse timing of Usu volcano, Japan, inferred from reworked ash deposits caused by debris avalanche

Re-investigation of the sector collapse timing of Usu volcano, Japan, inferred from reworked ash deposits caused by debris avalanche

Volcanic Lateral Collapse Processes in Mafic Arc Edifices: A Review of Their Driving Processes, Types and Consequences

Volcanic Debris Avalanches: Introduction and Book Structure

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