Large volcanic landslide and debris avalanche deposit at Meru, Tanzania

Delcamp, Audray; Kervyn, Matthieu; Benbakkar, Mhammed; Kwelwa, Shimba; Peter, D.

doi:10.1007/s10346-016-0757-8

Cited by 21 publications

(20 citation statements)

References 38 publications

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“…Meru is one of the active stratovolcanoes in northern Tanzania and had a small ash eruption in 1910 CE (Global Volcanism Program, 2013). Except for an early, well-documented large-scale sector collapse and its associated debris avalanche deposit, estimated to be early Holocene (Hecky, 1971;Delcamp et al, 2017), previous to our work, the pre-historic eruptive history of Meru volcano is poorly constrained.…”

Section: Discussionmentioning

confidence: 71%

“…Despite these deposits being widely dispersed and representing a large Plinian eruption, they are not found on the eastern side of the volcano nor in the summit crater depression. This lack of deposits in the east may be largely explained by a combination of predominant dispersal towards the edifice and left the large Momella debris avalanche deposit which dominates the volcanic geology in the east (Delcamp et al, 2017). The radiocarbon ages obtained in this study strongly suggest that the pyroclastic deposits are of the latest Pleistocene age (covering a range of ca.…”

Section: Stratigraphic Recordmentioning

confidence: 70%

“…The main central edifice has been breached on its eastern side, forming a horseshoe-shaped headwall, interpreted to result from a single large scale flank collapse, which produced a 20 ± 2 km 3 massive debris avalanche deposit (Momella DAD, Delcamp et al, 2017), reaching the western lower slopes of Kilimanjaro (Wilkinson et al, 1986;Delcamp et al, 2016). Deposits from two older collapses were identified on the northwestern (Lemurge DAD) and northeastern (Little Meru DAD) lower flanks (Delcamp et al, 2016;Fig.…”

Section: Tectonic Setting and Geological Contextmentioning

confidence: 99%

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The late Quaternary eruptive history of Meru volcano, northern Tanzania

Kisaka

Fontijn

Shemsanga

et al. 2021

Journal of Volcanology and Geothermal Research

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Mt. Meru, in the northern Tanzania divergence zone within the East African Rift System, is a 14 historically active volcano, with its last eruption in 1910CE. The flank deposits of Meru are dominated 15 by lava flows, debris avalanche deposits as well as major pyroclastic formations, indicative of Plinian-16 style eruptions. The stratigraphy, spatial extent, and chronology of these pyroclastic deposits have, 17 however, not been systematically studied. Here we report on the detailed reconstruction of the 18 stratigraphy and eruptive dynamics of Late Quaternary Meru explosive eruptions, based on field 19 investigations, geochronological and geochemical analyses. The findings indicate that Meru had at 20 least three moderate-to-large-scale explosive eruptions over the past 40,000 years. The oldest Meru 21 explosive event we recognize (MXP1) generated pyroclastic density currents (PDCs), while the second 22 (MXP2), and the third, most intense explosive event (MXP3), generated both pyroclastic fall and 23 PDCs. Conventional radiocarbon dating of 6 palaeosols underlying MXP2 and MXP3, dated ~34.1-24 38.5 kacalBP and ~31.5-36.9 kacalBP respectively, suggesting they may have followed each other 25 relatively close in time. The compositional range of pumice lapilli of both MXP2 and MXP3 is limited 26 to tephriphonolite-phonolite. Dispersal and thickness data of the better preserved and larger MXP3 27 deposits suggest a minimum bulk volume of 2.5 km 3 of pumice fallout and 1.2 km 3 of PDCs, 28 respectively, which corresponds to a total erupted mass of at least 2.74×10 12 kg and a magnitude of 29 5.4. Similar large-scale eruptions in the future would have considerable impacts on the nearby large 30 urban population in Arusha city and its suburbs. This new information is, therefore, vital for the long-31 term volcanic hazard assessment in Northern Tanzania.

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Section: Discussionmentioning

confidence: 71%

Section: Stratigraphic Recordmentioning

confidence: 70%

Section: Tectonic Setting and Geological Contextmentioning

confidence: 99%

See 1 more Smart Citation

The late Quaternary eruptive history of Meru volcano, northern Tanzania

Kisaka

Fontijn

Shemsanga

et al. 2021

Journal of Volcanology and Geothermal Research

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“…A debris avalanche is the product of a large-scale sectorcollapse of a volcanic edifice, often triggered by intrusion, hydrothermal variation, earthquake, intense rainfall, or ice melt [1,2]. This mass of rock fragments and soil moves rapidly down a steep mountain slope or hillside, and produces a debris avalanche deposit (DAD).…”

Section: Introductionmentioning

confidence: 99%

“…the maximum elevation of the moved mass, and runout distance (L). Several studies also suggest to take into account the ratio V/L between collapse volume (V) and run-out distance (L) [2]. DAD can be classified into three different categories due to its lithofacies: syneruptive DAD (bezymianny and Bandai-type with polymodal grain-size); hybrid DAD (gravitational flows, collisional texture, coarsely stratified, poorly sorted breccias); and lahar-transform DAD (rapid flow dynamics, sand fraction of hyperconcentrated flow deposits) [6].…”

Section: Introductionmentioning

confidence: 99%

Hummocky terrain of the Kalibabak debris avalanche deposit, Lombok Island, Indonesia

et al. 2020

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The debris avalanche deposit (DAD) coverage can drastically modify the surrounding landscape of volcanoes. DAD can be distinguished by hummocky irregular surface, jigsaw fissure, and mixing horse-shoe shape. Due to its particular shape of a hummock, the topography can be easily identified using DEM (Digital Elevation Model) and satellite imagery. The aim of this study is to characterize hummocky terrain in Lombok Island, which is located in the Kalibabak formation on the Geological map through the geomorphic approach. Hummocky terrain in this study are analyzed using DEM data from DEMNAS (DEM Nasional: 0.27-arcsecond resolution). Our study of this DAD encompasses seven variables, namely H/L ratio, numbers hummocks, distance to source, slope, area (size), relative height, topographic section, and hummock-spreading shape. A minimum of 756 hills derived from this DEM are considered as hummocks from this DAD, which extends ~18 km (NS) and ~25 km (WE) in the central part of Lombok Island. With an area of ~200 km2 and a volume estimated around 8.8 km3, the Kalibabak DAD is more than three times larger than the one of the Mount St-Helens in 1980. The morphology of hummocky terrain is bounded by a sudden change of slope, which is indicated by a river confluence. Average hummock size is 2.7 ha and average distance between each hummock is 150 m to 300 m. The hummocks are characterized by steep slopes (25 % to 45 %) at the boundary to colluvium plain (debris deposit), which makes them easy to identify using DEM. Hummocks spreading distribution forms a conical-like shape with a H/L ratio of 0.13. The spreading distribution shape, the H/L and V/L ratios are useful as an input for reconstructing the mechanism of debris avalanche emplacement.

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