Geomechanical Characterization of Submarine Volcano-Flank Sediments, Martinique, Lesser Antilles Arc

Lafuerza, Sara; Friant, Anne Le; Manga, Michael; Boudon, Georges; Villemant, Benoı̂t; Stroncik, Nicole A.; Voight, B.; Hornbach, M. J.; Ishizuka, Osamu

doi:10.1007/978-3-319-00972-8_7

Cited by 12 publications

(26 citation statements)

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“…Deposit 1 is ∼135 m thick at this core site located 78 km offshore from Montagne Pelée volcano (Figures , , and ). Lithostratigraphic descriptions show that sediment cored at site U1399 consists entirely of seafloor sediment and is dominated by a combination of hemipelagic mud with interbedded tephra layers and volcaniclastic turbidite deposits (Figures and ) [ Lafuerza et al ., ]. No debris avalanche deposits comprising blocky material from the subaerial volcanic edifice were recognized.…”

Section: Resultsmentioning

confidence: 99%

“…We recovered 434 core sections containing 2384 m of seafloor sediment samples. Information collected included physical properties on cores (thermal conductivity, shear strength, natural gamma ray emissions, P wave, magnetic susceptibility, density), and data obtained in situ by downhole logging operations (gamma rays, P wave, magnetic susceptibility, resistivity) [ Manga et al ., , Le Friant et al ., , Lafuerza et al ., , Wall‐Palmer et al ., ]. Table summarizes the location and characteristics of each hole at every site.…”

Section: Overview Of Iodp Expedition 340–datamentioning

confidence: 99%

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Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODPExpedition 340

Friant

Ishizuka

Boudon

et al. 2015

Geochem Geophys Geosyst

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IODP Expedition 340 successfully drilled a series of sites offshore Montserrat, Martinique and Dominica in the Lesser Antilles from March to April 2012. These are among the few drill sites gathered around volcanic islands, and the first scientific drilling of large and likely tsunamigenic volcanic island-arc landslide deposits. These cores provide evidence and tests of previous hypotheses for the composition and origin of those deposits. Sites U1394, U1399, and U1400 that penetrated landslide deposits recovered exclusively seafloor sediment, comprising mainly turbidites and hemipelagic deposits, and lacked debris avalanche deposits. This supports the concepts that i/ volcanic debris avalanches tend to stop at the slope break, and ii/ widespread and voluminous failures of preexisting low-gradient seafloor sediment can be triggered by initial emplacement of material from the volcano. Offshore Martinique (U1399 and 1400), the landslide deposits comprised blocks of parallel strata that were tilted or microfaulted, sometimes separated by intervals of homogenized sediment (intense shearing), while Site U1394 offshore Montserrat penetrated a flat-lying block of intact strata. The most likely mechanism for generating these large-scale seafloor sediment failures appears to be propagation of a decollement from proximal areas loaded and incised by a volcanic debris avalanche. These results have implications for the magnitude of tsunami generation. Under some conditions, volcanic island landslide deposits composed of mainly seafloor sediment will tend to form 420Geochemistry, Geophysics, Geosystems PUBLICATIONS smaller magnitude tsunamis than equivalent volumes of subaerial block-rich mass flows rapidly entering water. Expedition 340 also successfully drilled sites to access the undisturbed record of eruption fallout layers intercalated with marine sediment which provide an outstanding high-resolution data set to analyze eruption and landslides cycles, improve understanding of magmatic evolution as well as offshore sedimentation processes.

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Section: Resultsmentioning

confidence: 99%

Section: Overview Of Iodp Expedition 340–datamentioning

confidence: 99%

Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODPExpedition 340

Friant

Ishizuka

Boudon

et al. 2015

Geochem Geophys Geosyst

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“…Lafuerza et al . [] analyzed the upper 200 m of cores at Sites U1397, U1398, U1399, and U1400 of the IODP expedition 340. They demonstrated that low hydraulic conductivity of hemipelagic sediments causes low rates of dewatering in turbidity current deposits and tephra layers, leading to excess pore fluid pressures with depth.…”

Section: Discussionmentioning

confidence: 99%

Composition, geometry, and emplacement dynamics of a large volcanic island landslide offshore Martinique: From volcano flank‐collapse to seafloor sediment failure?

Brunet

Friant

Boudon

et al. 2016

Geochem Geophys Geosyst

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+33 (0) 1 83 95 76 38Key points: -First drilling into submarine landslide deposits offshore volcanic island -Large (300 km 3 ) submarine landslide deposit offshore Martinique comprises mainly deformed seafloor sediment, in a single frontally emergent morphology Research ArticleGeochemistry, Geophysics, Geosystems DOI 10.1002/2015GC006034This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of This article is protected by copyright. All rights reserved. 2 AbstractLandslides are common features in the vicinity of volcanic islands. In this contribution, we investigate landslides emplacement and dynamics around the volcanic island of Martinique based on the first scientific drilling of such deposits. The evolution of the active Montagne Pelée volcano on this island has been marked by three major flank-collapses that removed much of the western flank of the volcano. Subaerial collapse volumes vary from 2 to 25 km 3 and debris avalanches flowed into the Grenada Basin. High-resolution seismic data (AGUADOMAR -1999, CARAVAL -2002 and GWADASEIS -2009) is combined with new drill cores that penetrate up to 430 m through the three submarine landslide deposits previously associated to the aerial flank-collapses (Site U1399, Site U1400, Site U1401, IODP Expedition 340, Joides Resolution, March-April 2012). This combined geophysical and core data provide an improved understanding of landslide processes offshore a volcanicisland. The integrated analysis shows a large submarine landslide deposit, without debris avalanche deposits coming from the volcano, comprising up to 300 km 3 of remobilized seafloor sediment that extends for 70 km away from the coast and covers an area of 2100 km 2 .Our new data suggest that the aerial debris avalanche deposit enter the sea but stop at the base of submarine flank. We propose a new model dealing with seafloor sediment failures and landslide propagation mechanisms, triggered by volcanic flank-collapse events affecting Montagne Pelée volcano. Newly recognized landslide deposits occur deeper in the stratigraphy, suggesting the recurrence of large-scale mass-wasting processes offshore the island and thus, the necessity to better assess the associated tsunami hazards in the region.This article is protected by copyright. All rights reserved. IntroductionFlank-instabilities are a recurrent process in the long-term evolution of many volcanoes [Siebert, 1984;McGuire, 1996]. Exceptionally large volcanic landslides have been recognized offshore oceanic intraplate islands such as Hawaii [Moore et al., 1989, Moore et al., 1994, the Canary Islands [Carracedo, 1999; Masson et al., 2002], La Réunion Island [Labazuy, 1996; Oehler et al., 2004Oehler et al., , 2008 and in subduction zones such as the LesserAntilles [Deplus et al., 2001; Le Friant et al., 2003a,b;Boudon et al., 2007]. The scale of some of these events exceeds the la...

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“…Our analysis at site U1399 implies near‐lithostatic fluid pressures in some sediment at depths between 90 and 160 mbsf. Results at U1399 generally agree with analog laboratory experiments and numerical models that infer generally lower permeability and higher sustained pore pressures in distal turbidity deposits [e.g., Iverson , ; Lafuerza et al ., ]. Low permeability combined with high sedimentation rates can lead to elevated fluid pressures.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, Lafuerza et al . [] attribute the overconsolidation at nearby site U1399, not to erosion, but to a secondary compression caused by deformation. Contractive sediment can also develop high pore pressures and liquefy owing to cyclic shear deformation, such as that produced by earthquakes.…”

Section: Implications For Pore Pressure Developmentmentioning

confidence: 99%

Permeability and pressure measurements in Lesser Antilles submarine slides: Evidence for pressure‐driven slow‐slip failure

et al. 2015

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Recent studies hypothesize that some submarine slides fail via pressure‐driven slow‐slip deformation. To test this hypothesis, this study derives pore pressures in failed and adjacent unfailed deep marine sediments by integrating rock physics models, physical property measurements on recovered sediment core, and wireline logs. Two drill sites (U1394 and U1399) drilled through interpreted slide debris; a third (U1395) drilled into normal marine sediment. Near‐hydrostatic fluid pressure exists in sediments at site U1395. In contrast, results at both sites U1394 and U1399 indicate elevated pore fluid pressures in some sediment. We suggest that high pore pressure at the base of a submarine slide deposit at site U1394 results from slide shearing. High pore pressure exists throughout much of site U1399, and Mohr circle analysis suggests that only slight changes in the stress regime will trigger motion. Consolidation tests and permeability measurements indicate moderately low (~10−16–10−17 m2) permeability and overconsolidation in fine‐grained slide debris, implying that these sediments act as seals. Three mechanisms, in isolation or in combination, may produce the observed elevated pore fluid pressures at site U1399: (1) rapid sedimentation, (2) lateral fluid flow, and (3) shearing that causes sediments to contract, increasing pore pressure. Our preferred hypothesis is this third mechanism because it explains both elevated fluid pressure and sediment overconsolidation without requiring high sedimentation rates. Our combined analysis of subsurface pore pressures, drilling data, and regional seismic images indicates that slope failure offshore Martinique is perhaps an ongoing, creep‐like process where small stress changes trigger motion.

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Geomechanical Characterization of Submarine Volcano-Flank Sediments, Martinique, Lesser Antilles Arc

Cited by 12 publications

References 16 publications

Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODPExpedition 340

Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODPExpedition 340

Composition, geometry, and emplacement dynamics of a large volcanic island landslide offshore Martinique: From volcano flank‐collapse to seafloor sediment failure?

Permeability and pressure measurements in Lesser Antilles submarine slides: Evidence for pressure‐driven slow‐slip failure

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