Pressure influences both magma production and the failure of magma chambers. Changes in pressure interact with the local tectonic settings and can affect magmatic activity. Present-day reduction in ice load on subglacial volcanoes due to global warming is modifying pressure conditions in magmatic systems. The large pulse in volcanic production at the end of the last glaciation in Iceland sugges...

Calderas are collapse structures related to the emptying of magmatic reservoirs, often associated with large eruptions from long-lived magmatic systems. Understanding how magma is transferred from a magma reservoir to the surface before eruptions is a major challenge. Here we exploit the historical, archaeological and geological record of Campi Flegrei caldera to estimate the surface deformatio...

Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness r...

Very large volume (>1000 km of magma) crystal-rich dacitic ignimbrites that lack pronounced evidence of fractional crystallization or vertical zonation erupt in some continental magmatic arcs (e.g. the Lund Tuff of the Great Basin and the Fish Canyon Tuff of Colorado in western USA). Apparently, their magma chambers were only modestly heterogeneous and not systematically zoned from top to botto...

[1] A dense ocean bottom seismometer array recorded more than 7,300 microearthquakes between October 2003 and April 2004 on the fast spreading East Pacific Rise at 9°50′ N. A previous initial analysis of these data revealed the general structure of an along‐axis oriented hydrothermal circulation cell, with an inferred down‐flow zone near a 4th‐order axial discontinuity, a horizontal band of sei...

Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. Th...

[1] Side-scan sonar, submersible observations and sampling of lava flows from the East Pacific Rise, 17 –19 S constrain the character and variability of submarine volcanic eruptions along mid-ocean ridges. Nine separate lava sequences were mapped using relative age and lithological contrasts among recovered samples. Axial lengths activated during eruptive episodes range from 1 to >18 km; indivi...

The Hezar Igneous Complex (HIC) in the south-eastern part of Urumieh-Dokhtar magmatic arc, is the most prominent magmatic feature in the Kerman Porphyry Copper Belt, that understanding magmatic evolution of which may shed light on the tectonomagmatic development of this less-studied part of an important magmatic arc in the Neotethys realm. The HIC has been developed in the the intersection of t...

In large magma chambers, gradients of temperature and composition develop due to cooling and to fractional crystallization. Unstable density differences lead to differential motions between melt and crystals, and a major goal is to explain how this might result in chemical differentiation of magma. Arriving at a full description of the physics of Crystallizing magma chambers is a challenge beca...

A Comparison of Theoretical Inferences for Magmatic Supply on Mars S. Baloga Relative Ages of Martian Volcanoes N. G. Barlow Martian Mantle Primary Melts C M. Bertka, Z R. Holloway, and V. Pan Magmatic Sulfides on Mars R. G. Bums Constraints on Eruption Rates and Cooling of Three Lava Flows at Alba Z Crisp Hadriaca Patera: Evidence for Pyroclastic Volcanism in the Hellas Region of Mars D.A. Cro...