Mountains, magmas and mushes

Thursday 25th February 2016 @ 19:00

Non-Member: £12.00 ; Staff: £5.00 ; Student: £3.00

Professor Matthew Jackson, TOTAL Chair of Geological Fluid Mechanics, Dept. of Earth Science and Engineering, Imperial College London

Recent research is challenging the traditional model of volcano plumbing.  Discover how we now think magma is supplied to volcanoes, and the implications for eruption frequency and prediction, and evolution of the Earth’s crust.

Eight hundred million people worldwide live within 100km of a volcano that has the potential to erupt.  A major scientific challenge is to predict when an eruption will occur.  Yet recent data are showing that we have fundamentally misunderstood the nature of the ‘plumbing system’ that stores and delivers magma (hot, liquid rock) to volcanoes.  Magma plumbing systems do not resemble the pictures familiar to many from TV programmes, web searches and textbooks. Scientists are being forced to revise their understanding of volcanic processes……from the ground up!

Almost exactly 100 years ago, the Canadian-born scientist Norman L. Bowen, working at the Carnegie Institution of Washington, USA, developed the conceptual model of volcano plumbing systems that is still widely used today.

In this model, a volcano sits above one or more large holes in the ground termed ‘magma chambers’ which are filled with hot, liquid magma.  Processes within the magma chamber(s) dictate when a volcano will erupt, the type of lava that will be erupted, and the style of eruption: some eruptions are effusive (such as those in Hawaii); others can be explosive (such as the AD 79 eruption of Vesuvius, described by Pliny).  Nearly all models of volcanoes assume the presence of a large, liquid magma chamber.  

The problem is that numerous recent experiments, using geophysical techniques to image such a magma chamber beneath an active volcano, have failed.  No such magma chambers have been observed.  Moreover, numerical modelling has shown that liquid magma chambers are not thermally viable: to keep the magma in the chamber hot enough to remain liquid over long (geological) timescales requires new magma to be added at unrealistically high rates. 

The question is: if large, liquid magma chambers do not exist, what is the alternative?  What does the magma plumbing system of a volcano look like, and what are the implications for modelling and predicting volcanic eruptions?  What pictures will the textbooks of the future show?  And why is fluid dynamics important?  

Come along to find out!

Optionally followed by supper (this can be booked on the event booking form).
After the lecture a Friends' Table has been reserved at a local restaurant to entertain the speaker and for any of the audience who would like to join us to continue the evening's discussion. A two-course fixed price supper is served including wine, coffee and service charge.
Or if you have already booked for the event and now want to join us for supper Book Supper now

Venue: SAF Building, Imperial College London

Campus Map reference 33
on the Imperial College London Map