Marian B. Holness et al., Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK. Posted online 29 June 2012; doi: 10.1130/G33119.1.
Working out how long bodies of magma take to solidify is important if we want to understand how volcanoes behave. Until now this has been done using theoretical cooling models or by looking at how big the individual crystals are (the bigger the crystals the longer time they had to grow). Here we show that the way the grain fit together gives us an accurate picture of how long magma took to solidify: the geometry of three-grain junctions is a highly sensitive speedometer for crystallization times between 10 and 1000 years.
Gravity fluctuations induced by magma convection at Kilauea volcano, Hawai'i
Daniele Carbone and Michael P. Poland, Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Osservatorio Etneo, Catania 95125, Italy. Posted online 29 June 2012; doi: 10.1130/G33060.1.
This paper reports on the first continuous gravity measurements accomplished at Kilauea volcano in Hawai'i. Daniele Carbone and Michael Poland recorded the shortest-period gravity oscillations related to volcanic activity that have ever been detected, which they associate with convection in a shallow magma chamber. Rapid magma convection has long been hypothesized at persistently active volcanoes based on numerical simulations, but supporting data are largely absent from the literature. Carbone and Poland interpret their gravity data to be the first geophysical fingerprint of convection occurring over a time scale on the order of minutes in a shallow magma reservoir. The implications of the paper are twofold: (1) the results provide a new perspective on how magma circulates at Kilauea and other persistently active volcanoes, which can impact the understanding of gas emissions, seismic activity, and eruption
|Contact: Kea Giles|
Geological Society of America