Showing papers in "Journal of Volcanology and Geothermal Research in 2006"

TL;DR: In this article, the authors proposed a four-stage model for kimberlite eruptions to explain the main geological relationships of kimbersites, where the early flow exit conditions are overpressured with choked flow conditions; an exit velocity of ∼200m/s is estimated as representative.

TL;DR: In this paper, a seismic trigger model based on brittle failure of magma in the glass transition is proposed, where the trigger source location marks the transition from ductile conduit flow to friction-controlled magma ascent.

TL;DR: In this article, a database and spreadsheet program is presented to estimate the true crystal habit from raw 2D measurements, which can then be used to investigate magmatic processes with more certainty.

TL;DR: In this article, the authors quantified the thermal effects of two-phase flow in the pore space of shallow silicic mushes that have reached their rheological lock-up point (i.e., rigid porous medium, crystallinity z50 vol%).

TL;DR: In this article, a method was proposed to estimate the decompression rate by using bubble number density (BND) data of natural pumice samples from volcanic eruptions, and it was found that decompression rates increase in the range from 10 6 to 10 8 ǫ(Pa/s) with the eruption column heights.

TL;DR: In this article, a study of the surface deformation occurring in the island of Ischia, which is based on applying the Differential Synthetic Aperture Radar Interferometry (DInSAR) algorithm referred to as Small BAseline Subset (SBAS) technique, is presented.

TL;DR: A simple model for predicting effects of volcanic ashfall on water supplies using available information on ash composition has been proposed in this paper, which suggests that the primary effects of concern are likely to be an increase in acidity (decrease in pH), and increases in concentrations of the metals aluminium, iron, and manganese.

TL;DR: In this article, the authors investigate the effects of viscoelastic rheologies surrounding a vertically dipping prolate spheroid source during an active period of time-dependent deformation between 1995 and 2000 at Long Valley caldera.

TL;DR: In this paper, the authors estimate the geometry of the sill assuming a horizontal, uniformly pressurized crack with unknown periphery and depth, and find the best-fitting sill to be located beneath Sierra Negra's inner caldera at a depth of about 2 km.

TL;DR: A review of the achievements of volcano geodesy in Iceland during the last 15 years can be found in this article, where a variety of geodetic techniques, including leveling, electronic distance measurements, campaign and continuous Global Positioning System (GPS) geodesys, and interferometric analysis of synthetic aperture radar images (InSAR).

TL;DR: In this article, the etna 122 BC basaltic eruption had two Plinian phases, each preceded and followed by weak phreatic and phreatomagmatic activity, suggesting that the 122 BC magma underwent coupled degassing linked to rapid ascent and decompression.

TL;DR: In this article, the authors presented a survey for the Colli Albani volcano (Roma, Italy) surveyed for the Geological Map of Italy at 1:50,000 scale (CARG Project), integrated with previous data, provide insights on caldera evolution.

TL;DR: In this paper, the authors used cross-correlation techniques to quantify the degree of similarity between low-frequency volcanic earthquakes and developed a method to sort events into families containing comparable waveforms.

TL;DR: In this paper, the first order definition of the modem submarine Kermadec arc between 30 degrees and 35 degrees S was established and two new volcanoes with basal diameters > 5 km were discovered or fully mapped for the first time; Giggenbacb, Macauley, Havre, Haungaroa, Kuiwai, Ngatoroirangi, Sonne, Kibblewhite and Yokosuka.

TL;DR: In this article, a coupled morphometric and stratigraphic analysis of several tens of parasitic pyroclastic cones of the SE flank of Mt. Etna volcano, Italy, is presented to explain the structure of a poorly understood, actively deforming zone.

TL;DR: Barren Island (BI) is a subduction-related volcanic island lying in the northeastern Indian Ocean, about 750 km north of the northern tip of Sumatra as mentioned in this paper, and the first historical eruption began in 1787 when a cinder cone grew in the center of a pre-historical caldera 2-km in diameter.

TL;DR: In this paper, an experimental device consisting of a transparent box (60 × 60 × 40 cm) filled with dry quartz sand and a water-filled latex balloon as a magma chamber analogue was used to record the temporal evolution of the collapse and track the evolution of fractures and faults.

TL;DR: In this article, the Ferrar large igneous province of Antarctica contains significant mafic volcaniclastic deposits, some of which are interpreted to fill large vent complexes, and they found several contrasting types, two of which were interpreted to have filled subterranean passageways forcefully opened from below into existing, nonconsolidated debris.

TL;DR: In this article, a series of rapid decompression experiments on three sets of natural samples from Unzen volcano, Japan were performed by dry sieving for particles larger than 250 μm and wet laser refraction for smaller particles.

TL;DR: In this paper, the first direct measurements of water in mafic melts from Arenal volcano, Costa Rica, were provided, where the authors performed ion microprobe analyses of olivine-hosted melt inclusions (MI) from the prehistoric ET3 and ET6 tephra layers.

TL;DR: In this paper, the authors investigated three volcanic centres from the Lago General Carrera-Buenos Aires area (46-47°S) located above the inferred position of the slab window corresponding to a segment subducted 6 Ma ago.

TL;DR: In this paper, the authors describe the micro-physics and parameterization of volcanic ash and hydrometeors through numerical experiments with the plume model ATHAM (Active Tracer High resolution Atmospheric Model) in order to determine the conditions that promote ash particle aggregation.

TL;DR: Clynne et al. as discussed by the authors found that plagioclase phenocrysts are engulfed during intrusion of basaltic to andesitic enclaves, which are composed of a densely packed network of micron-sized glass inclusions.

TL;DR: In this paper, a systematic geochemical survey of mineral and thermal water chemistry from the Azores archipelago was carried out, incorporating new data as well as results from the literature.

TL;DR: In this paper, the authors used multibeam bathymetry and a digital elevation model of the Hawaiian Islands to calculate the volumes of individual shield volcanoes and island complexes (Niihau, Kauai, Oahu, the Maui Nui complex, and Hawaii), taking into account subsidence of the Pacific plate under the load of the Hawaii Ridge.

TL;DR: The 5 April 2003 paroxysmal explosion at Stromboli volcano was one of the strongest explosive events of the last century as discussed by the authors, with bombs up to 4 m wide falling on the village of Ginostra, on the west flank of the island and destroying two houses.

TL;DR: In this paper, a coupling mechanism was proposed to explain local depart of the regional stress field, geometric array of extensional features, and final magmatic evolution in these volcanic domains of the Southern Andes.

TL;DR: The Central American volcanic arc supplies a significant proportion of the persistent annual global sulphur dioxide emissions from volcanoes as mentioned in this paper, with a mean total arc flux of SO2 of 4360 Mg day -1 or 8-16% of the annual estimated global volcanic SO2 flux to the troposphere.

TL;DR: In this paper, the authors present new numerical models of magma chambers hosted by crustal layers of contrasting mechanical properties, such as stiff lava flows and soft pyroclastic rocks.

TL;DR: In this article, the authors used X-ray tomography for pumice clasts from the Bishop Tuff to obtain a 3D map of the linear attenuation coefficient, which is a function of the atomic number and density of the material, and the Xray energy used.