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 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.
This contribution provides an analysis of the 1995–2009
eruptive period of Soufriere Hills volcano (Montserrat) from
a unique offshore perspective. The methodology is based on
five repeated swath bathymetric surveys. The difference
between the 2009 and 1999 bathymetry suggests that at
least 395 Mm3 of material has entered the sea. This proximal
deposit reaches 95 m thick and extends ∼7km from shore.
However, the difference map does not include either the
finer distal part of the submarine deposit or the submarine
part of the delta close to the shoreline. We took both
contributions into account by using additional information
such as that from marine sediment cores. By March 2009,
at least 65% of the material erupted throughout the eruption
has been deposited into the sea. This work provides an
excellent basis for assessing the future activity of the
Soufriere Hills volcano (including potential collapse), and
other volcanoes on small islands.
Abstract. The aragonite shell-bearing thecosome pteropods are an important component of the oceanic plankton. However, with increasing pCO2 and the associated reduction in oceanic pH (ocean acidification), thecosome pteropods are thought to be particularly vulnerable to shell dissolution. The distribution and preservation of pteropods over the last 250 000 years have been investigated in marine sediment cores from the Caribbean Sea close to the island of Montserrat. Using the Limacina Dissolution Index (LDX), fluctuations in pteropod calcification through the most recent glacial/interglacial cycles are documented. By comparison to the oxygen isotope record (global ice volume), we show that pteropod calcification is closely linked to global changes in pCO2 and pH and is, therefore, a global signal. These data are in agreement with the findings of experiments upon living pteropods, which show that variations in pH can greatly affect aragonitic shells. The results of this study provide information which may be useful in the prediction of future changes to the pteropod assemblage caused by ocean acidification.
We model the submarine emplacement of a debris avalanche generated by the last flank‐collapse event of Montagne Pelée volcano. We estimate the collapsed volume (1.7 km 3 ) using both the volume of the missing material in the horseshoe‐shaped structure and the volume of submarine deposits. This avalanche is treated as the gravitational flow of a homogeneous continuum. It is simulated by a finite‐difference model, solving mass and momentum conservation equations, that are depth‐averaged over the slide thickness. Numerical simulations show that the emplacement of this debris‐avalanche can be suitably modeled by a Coulomb‐type friction law with a variable friction angle below 10°. We propose that variations of the friction angle are mainly influenced by the thickness of the flowing mass.
Research Article| July 01, 2006 Submarine pyroclastic deposits formed at the Soufrière Hills volcano, Montserrat (1995–2003): What happens when pyroclastic flows enter the ocean? J. Trofimovs; J. Trofimovs 1Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar L. Amy; L. Amy 1Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar G. Boudon; G. Boudon 2Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France Search for other works by this author on: GSW Google Scholar C. Deplus; C. Deplus 2Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France Search for other works by this author on: GSW Google Scholar E. Doyle; E. Doyle 3Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar N. Fournier; N. Fournier 4Seismic Research Unit, The University of the West Indies, St Augustine, Trinidad, West Indies Search for other works by this author on: GSW Google Scholar M.B. Hart; M.B. Hart 5School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK Search for other works by this author on: GSW Google Scholar J.C. Komorowski; J.C. Komorowski 6Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France Search for other works by this author on: GSW Google Scholar A. Le Friant; A. Le Friant 6Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France Search for other works by this author on: GSW Google Scholar E.J. Lock; E.J. Lock 7School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK Search for other works by this author on: GSW Google Scholar C. Pudsey; C. Pudsey 8British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK Search for other works by this author on: GSW Google Scholar G. Ryan; G. Ryan 9British Geological Survey, Natural Environment Research Council, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK Search for other works by this author on: GSW Google Scholar R.S.J. Sparks; R.S.J. Sparks 10Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar P.J. Talling P.J. Talling 10Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar Author and Article Information J. Trofimovs 1Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK L. Amy 1Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK G. Boudon 2Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France C. Deplus 2Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France E. Doyle 3Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK N. Fournier 4Seismic Research Unit, The University of the West Indies, St Augustine, Trinidad, West Indies M.B. Hart 5School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK J.C. Komorowski 6Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France A. Le Friant 6Institut de Physique du Globe de Paris et Centre National de la Recherche Scientifique (CNRS) Case 89, 4 Place Jussieu, 75252 Paris, Cedex 05, France E.J. Lock 7School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK C. Pudsey 8British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK G. Ryan 9British Geological Survey, Natural Environment Research Council, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK R.S.J. Sparks 10Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK P.J. Talling 10Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK Publisher: Geological Society of America Received: 11 Nov 2005 Revision Received: 09 Feb 2006 Accepted: 13 Feb 2006 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 The Geological Society of America, Inc. Geology (2006) 34 (7): 549–552. https://doi.org/10.1130/G22424.1 Article history Received: 11 Nov 2005 Revision Received: 09 Feb 2006 Accepted: 13 Feb 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. Trofimovs, L. Amy, G. Boudon, C. Deplus, E. Doyle, N. Fournier, M.B. Hart, J.C. Komorowski, A. Le Friant, E.J. Lock, C. Pudsey, G. Ryan, R.S.J. Sparks, P.J. Talling; Submarine pyroclastic deposits formed at the Soufrière Hills volcano, Montserrat (1995–2003): What happens when pyroclastic flows enter the ocean?. Geology 2006;; 34 (7): 549–552. doi: https://doi.org/10.1130/G22424.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The Soufrière Hills volcano, Montserrat, West Indies, has undergone a series of dome growth and collapse events since the eruption began in 1995. Over 90% of the pyroclastic material produced has been deposited into the ocean. Sampling of these submarine deposits reveals that the pyroclastic flows mix rapidly and violently with the water as they enter the sea. The coarse components (pebbles to boulders) are deposited proximally from dense basal slurries to form steep-sided, near-linear ridges that intercalate to form a submarine fan. The finer ash-grade components are mixed into the overlying water column to form turbidity currents that flow over distances >30 km from the source. The total volume of pyroclastic material off the east coast of Montserrat exceeds 280 × 106 m3, with 65% deposited in proximal lobes and 35% deposited as distal turbidites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Abstract Hole U1395B, drilled southeast of Montserrat during Integrated Ocean Drilling Program Expedition 340, provides a long (>1 Ma) and detailed record of eruptive and mass‐wasting events (>130 discrete events). This record can be used to explore the temporal evolution in volcanic activity and landslides at an arc volcano. Analysis of tephra fall and volcaniclastic turbidite deposits in the drill cores reveals three heightened periods of volcanic activity on the island of Montserrat (∼930 to ∼900 ka, ∼810 to ∼760 ka, and ∼190 to ∼120 ka) that coincide with periods of increased volcano instability and mass‐wasting. The youngest of these periods marks the peak in activity at the Soufrière Hills volcano. The largest flank collapse of this volcano (∼130 ka) occurred toward the end of this period, and two younger landslides also occurred during a period of relatively elevated volcanism. These three landslides represent the only large (>0.3 km 3 ) flank collapses of the Soufrière Hills edifice, and their timing also coincides with periods of rapid sea level rise (>5 m/ka). Available age data from other island arc volcanoes suggest a general correlation between the timing of large landslides and periods of rapid sea level rise, but this is not observed for volcanoes in intraplate ocean settings. We thus infer that rapid sea level rise may modulate the timing of collapse at island arc volcanoes, but not in larger ocean‐island settings.
<p>The early development and growth of seamounts are poorly known as the birth of a volcano on the sea bottom has been rarely observed. The on-going Mayotte seismo-volcanic crisis is associated with the formation of a new seafloor volcano at a water depth of 3300 m and provides the opportunity to study its early development.</p><p>Four oceanographic cruises, MAYOBS 1 to 4, were carried out between May and July 2019 aboard the French R/V Marion Dufresne. High resolution bathymetry and backscatter data as well as sub-bottom profiler, gravity and magnetic profiles were collected during each cruise. A dense network of profiles has been achieved over the new volcano at different epochs, allowing to assess its detailed morphology and the evolution through time. During MAYOBS4, a deep-towed underwater camera provided sea bottom videos and photos on the volcano.</p><p>First results indicate that the new volcano is still growing at the end of July 2019. Repetitive surveys in May, June and July 2019 allow to document the morphological evolution of the volcano, to estimate the volume of material emplaced between each epoch and to discuss the emitted lava rate.</p><p>The new volcano has a starfish shape and is now 820 m high. Steep slopes are observed close to the summit and several radial ridges developed from its central part, displaying hummocky morphology similar to the ones observed along mid oceanic axial volcanic ridges. At the bottom, flat areas with high backscatter could indicate channelized lava flows emplaced at higher effusion rates. The morphological analysis combined with video imagery brings constraints to the eruptive processes yielding to the formation of a nascent volcano.</p><p>&#160;</p>
Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
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