Magma is transported in brittle rock through dikes and sills. This movement may be accompanied by the release of seismic energy that can be tracked from the Earth’s surface. Locating dikes and deciphering their dynamics is therefore of prime importance in understanding and potentially forecasting volcanic eruptions. The Seismic Amplitude Ratio Analysis (SARA) method aims to track melt propagati...

a r t i c l e i n f o We present a new criterion for primary fragmentation of natural rock samples in shock-tube experiments, and new formulae for the effective strength of natural rock samples, for the size of primary fragments, and for fragmentation velocities. These formulae and the fragmentation criterion are given in terms of the physical properties of the rock and in terms of experimental...

[ 1] Volcan Ecuador, a young, active shield volcano at the northwest tip of Isabela Island, Galá pagos, experienced at least one sector collapse event that removed its western half. The compositions of lavas exposed in the old caldera wall and fault scarps dissecting the outer shield together with young postcollapse lavas provide insights into the history of this volcano. Ar/ Ar and cosmogenic ...

New and previously published micro-gravity data are combined with InSAR data, precise levelling and GPS measurements to produce a model for the processes operating at Krafla volcano, 20 years after its most recent eruption. The data have been divided into two periods: from 1990 to 1995 and from 1996 to 2003 and show that the rate of deflation at Krafla is decaying exponentially. The net micro-g...

Crystallization coupled with gravity removal of depleted interstitial melt has long been recognized as a mechanism of magma differentiation. Similarly, heat released by synplutonic basaltic magma intrusions has long been recognized as capable of driving convection in granite chambers. Direct evidence of these processes has seldom been described in granites. In the Tavares pluton, we mapped a nu...

Timescales of magma ascent in conduit models are typically assumed to be much longer than crystallization and gas exsolution for basaltic eruptions. However, it is now recognized that basaltic magmas may rise fast enough for disequilibrium processes to play a key role on the ascent dynamics. The quantification of the characteristic times for crystallization and exsolution processes are fundamen...

In recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thu...

We use 2000–2012 InSAR data frommultiple satellites to investigate magma storage in Kīlauea’s east rift zone (ERZ). The study period includes a surge in magma supply rate and intrusion-eruptions in 2007 and 2011. The Kupaianaha area inflated by ~5 cm prior to the 2007 intrusion and the Nāpau Crater area by ~10 cm following the 2011 intrusion. For the Nāpau Crater area, elastic modeling suggests...

[1] We use 2006–2009 ALOS Interferometric Synthetic Aperture Radar data over the entire west Sunda arc, Indonesia, home of 13% of the world’s active volcanoes, to derive arcwide time-dependent ground deformation data. We present unambiguous evidence of inflation at six volcanoes, three of which erupted after the observation period.We show that these volcanoes have shallow magma reservoirs at 1–...

We investigate the problem of estimating magma chamber geometry using InSAR observations of Sierra Negra volcano, Galápagos. Ascending and descending interferograms are combined to determine vertical and one horizontal component of displacement. The ratio of maximum horizontal to vertical displacement suggests a sill-like source. Spherical or stock-like bodies are inconsistent with the data. We...