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While the early development of basaltic lava flows is relatively well understood, long-lived effusive activity (>~3 weeks) results in complex flow field architectures with multiple ephemeral vents feeding short-lived flows, that may become tubed. The processes controlling flow structures and lifetimes are not fully understood; some may be governed by effusion rate or topography, others by rheological changes at the flow front. Detailed analyses of flow field development will improve our understanding of the above processes, and others including accidental breach formation. During the final month of the 13 May 2008 - 6 July 2009 eruption of Mt Etna, we installed four Canon EOS 450D cameras (3 visible and one modified to collect infrared images) at critical locations to record images (at 5 or 15 minute intervals) of the active flows. The image sequences show that multiple individual 'a'ā channel flows were often simultaneously active for hours to days, with lengths of tens to hundreds of metres. Mean flow lengths decreased over time, indicating diminishing effusion rates. Variations in the number and lengths of active flows, and the occurrence of pulses within channels are suggestive of shorter-term effusion rate fluctuations. Several flows roofed over on timescales of hours to a few days. Measured flow velocities and dimensions can be used to estimate rheological properties. Processes observed in these small flows have also been observed in larger flows, so we discuss implications for interpreting flow behaviour on larger spatial scales.

During effusive eruptions, property and infrastructure can be threatened by lava flow inundation. In order to maximise the effectiveness of the response to such an event, it is necessary to be able to reliably forecast the area that will be affected. One of the major controls on the advance of a lava flow is its rheology, which is spatially and temporally variable, and depends on many underlying factors. Estimating the rheological properties of a lava flow, and the change in these over space and time is therefore of the utmost importance. Here we report estimates of rheological properties made from geometric and velocity measurements on integrated topographic and image data using the method of Ellis et al. (2004) (Ellis B, Wilson L & Pinkerton H (2004) Estimating the rheology of basaltic lava flows. Lunar & Planetary Science XXXV Abst. 1550). These are then compared to the viscosity predicted from composition and temperature by the GRD model (Giordano D, Russell JK, & Dingwell DB (2008) Viscosity of Magmatic Liquids: A Model. Earth & Planetary Science Letters, 271, 123-134). During the 13 May 2008 - 6 July 2009 eruption of Mt Etna, Sicily, lava flows were emplaced into the Valle del Bove, reaching a maximum length of >6 km. Towards the end of the eruption, multiple channelized aa flows were active simultaneously, reaching tens to hundreds of metres in length. Flow lifetimes were of the order hours to days. In the last month of the eruption, we installed a Canon EOS 450D camera at Pizzi Deneri, on the north side of the Valle del Bove, to collect visible images at 15-minute intervals. On one day, topographic data (using a Riegl LPM-321 terrestrial laser scanner) and thermal images (using a FLIR Thermacam S40) were also collected from this location. The fronts of some of the larger flows were tracked through the time lapse image sequence. Using knowledge of the camera imaging geometry, the pixel tracks were reprojected onto the topographic surface to determine flow adv

While the early development of basaltic lava flows is relatively well understood, long-lived effusive activity (>~3 weeks) results in complex flow field architectures with multiple ephemeral vents feeding short-lived flows, that may become tubed. The processes controlling flow structures and lifetimes are not fully understood; some may be governed by effusion rate or topography, others by rheological changes at the flow front. Detailed analyses of flow field development will improve our understanding of the above processes, and others including accidental breach formation. During the final month of the 13 May 2008 - 6 July 2009 eruption of Mt Etna, we installed four Canon EOS 450D cameras (3 visible and one modified to collect infrared images) at critical locations to record images (at 5 or 15 minute intervals) of the active flows. The image sequences show that multiple individual 'a'ā channel flows were often simultaneously active for hours to days, with lengths of tens to hundreds of metres. Mean flow lengths decreased over time, indicating diminishing effusion rates. Variations in the number and lengths of active flows, and the occurrence of pulses within channels are suggestive of shorter-term effusion rate fluctuations. Several flows roofed over on timescales of hours to a few days. Measured flow velocities and dimensions can be used to estimate rheological properties. Processes observed in these small flows have also been observed in larger flows, so we discuss implications for interpreting flow behaviour on larger spatial scales.

It is often taken as a given that higher education shapes the politics of students. However, drawing on evidence from the British Election Study, Tom Fryer finds students’ political attitudes do not change radically during their studies. Instead, students make modest movements to the left and become less ethnocentric, indicating overall a slight shift of position, rather than a wholesale change of attitude.