1100 (CD-ROM). [9] Stofan, E.R. et al. (2001) Icarus, 152, 75-95. Table 1. Statistics relating to each morphological class in the catalogue. Volcano class Frequency Mean diameter

Query optimizers built on the Volcano/Cascades framework, which is based on transformation rules, are used in many commercial databases. Transformation rulesets proposed earlier for join order enumeration in such a framework either allow enumeration of joins with cross-products (which can significantly increase the cost of optimization), or generate a large number of duplicate derivations. In t...

Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edif...

Major volcano flank collapses strongly affect the underlying magmatic plumbing system. Here, we consider the magma storage zone as a liquid pocket embedded in an elastic medium, and we perform numerical simulations in two-dimensional axisymmetric geometry as well as in three dimensions in order to evaluate the consequences of a major collapse event. We quantify the pressure decrease induced wit...

[1] Lava dome eruptions are commonly characterized by large fluctuations in discharge rate with cyclic behaviour on time-scales ranging from hours to decades. Examples include Bezymianny volcano (Russia), Merapi (Java), Santiaguito (Guatemala), Mt St Helens (USA), Mt Unzen (Japan), and Soufrière Hills volcano (Montserrat). Previous models have assumed simple cylindrical conduits for magma trans...

In this paper, we summarize some recent results of measurements of temporal changes of active volcanoes using seismic noise cross-correlations. We first present a novel approach to estimate volcano interior temporal seismic velocity changes. The proposed method allows to measure very small velocity changes (≈ 0.1%) with a time resolution as small as one day. The application of that method to Pi...

Deformation monitoring systems seek to detect constant movements with time, varying movements with time or a sudden movement. A slow movement at the millimetre level will not be detected by comparing consecutive session solutions due to inaccuracies between sessions. However, comparisons over several sessions, or days, or weeks, could highlight slow consistent changes. The Allan variance is int...

Different worldwide volcanic areas are densely populated and urbanized. For instance, in Italy, despite being the most active volcano in Europe, Mt Etna is home to approximately one million people. During the last decades, the vulnerability of the Etnean area has increased exponentially due to continued, at times wild, urbanization, with the consequence that new eruptions may involve even great...

We present new radar-based techniques for efficient identification of surface changes generated by lava and pyroclastic flows, and apply these to the 1996 eruption of Manam Volcano, Papua New Guinea. Polarimetric Land P-band airborne synthetic aperture radar (SAR) data, along with a C-band DEM, were acquired over the volcano on 17 November 1996 during a major eruption sequence. The Lband data a...

At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the diffi...