Wednesday, November 21, 2012

Old School Volcanology

by Ben Kennedy and Emma Rhodes

We are oldschool physical volcanologists complete with hammers, compasses and maps, and we loved bashing rocks and getting covered in ash at Santiaguito. It felt a little like being trapped between the devil and deep blue sea with Santa Maria shedding rock falls on one side and Santiaguito chucking out pyroclastic flows on the other but we wouldn't have it any other way.  Emma will spend the next month climbing all over the Santiaguito dome to map the surface geological structures and internal textures of the lava. This should allow us to contrast the textures associated with lava, when it overtops the crater as a lava flow with when it pushes up a vertical spine of mostly solid lava. It is important to understand this transition in activity as vertical spines of lava are more likely to collapse to form large hazardous pyroclastic flows than long fluidal lava flows. Emma hopes to apply what she has learnt at Santiaguito to a lava flow from the recently active Te Maari vent at Tongariro, New Zealand. In addition, Ben collected bubbly bombs that he will cook in an oven at 1000°C to cause bubbles to grow and collapse in the molten rock. This growth and collapse of bubbles in magma is a possible explanation for some of the inflation and deflation events that other members of the team observe and record.

1 comment:

  1. Great! There are lots of things to think about relating to the surface of the domes. Like all those arcquate structures, and the linear vents, and all that stuff that I've never been able to wrap my head around. You can also see the progression from very spiny domes (La Mitad and Monje) to less spiny El Brujo, which also produced the first long lava flow in the 1960 - 70's. those lava flows are easy to access, so you could sample the whole transition from endogenous to exogenous. Anyway, enough with the ranting... keep us updated about the research!