We continue to share information that the Team « Erebus » put on its Facebook page. (Mount Erebus Volcano Observatory).
The Erebus team on the ice goes by its National Science Foundation project number G081. The G081 team is undertaking a varied menu of research projects each with their own goals and objectives.
1) GPS measurements .
A New Mexico Tech team is making campaign (short term) GPS measurements of 8 permanent bench marks around Ross Island and on the summit area of Erebus volcano. This supplements 6 permanent continuously running GPS scattered around the volcano. The GPS date will examine deformation of the crater and look at how Ross Island is sinking under its own weight.
2) Volcanic gas emissions.
Annual measurements are made of the composition and quantities of volcanic gases emitted from the lava lakes in the summit crater using IR and UV spectrometers. The data are used to monitor the behavior of the underlying magmatic system and for annual comparisons to assess if any major changes are happening at depth in the volcano. This year one specialist in volcanic gas emissions is characterizing the nature of the aerosols (tiny gas and solid particles) which provide insight into how the dissolved volcanic gas becomes bubbles and drives the movement of the magma to the surface. The unique chemical signature of the aerosols can be used to identify the dispersion of the Erebus plume around Antarctica and its deposition in the snow.
3) Seismic Observations.
Seismic signals caused by eruptions and earth movements in the volcano are monitored year round to look for changes in the activity that may herald the onset of larger eruptions. The network of 4 older short-period and 5 newer broadband seismometers need annual maintenance and replacement of batteries and components that fail during the harsh Antarctic winters.
4) Magma Composition.
Periodically Erebus has small eruptions that can hurl large volcanic bombs out of the lava lake onto the crater rim where they can be sampled for analysis. The magma in the laka is a very special and unique composition called phonolite. Large anorthoclase feldspar crystals in the phonolite record how the magma in the deep storage chamber circulates. Although the lava lake has remained uniform in composition for over 30 years it is prudent to look for changes in the composition which could affect the eruptive activity.
5) Lava lake observations.
The lava lake(s) which are one of the unique characteristics of Erebus volcano are the top of the deeper magmatic system that metaphorically is the heart of the volcano. We image the main lake using a thermal IR camera to monitor circulation and thermal fluxes. A laser range finder called a LIDAR give us precise location information and monitors a persistent 10-16 minute pulsation of the lake surface. This year we are testing a new novel radar system especially designed and built for Erebus to make better observations of the main lava lake and its motions. ts.
Age dating of older lavas on a volcano gives insight into the eruptive history and can be used to predict future activity. We have used the build-up of an isotope of He produced by bombarding cosmic rays to date the youngest lavas. We are working cooperatively with colleagues from the Korean Polar Research Institute to use the same technique to examine the recent eruptive activity of Mt Melbourne another “active” volcano 200 miles north of Erebus. While in the area we are searching for volcanic ash erupted from Erebus and other local volcanoes. Dark layers of ash are common in “blue” ice areas and are a valuable record of the volcanic eruptions which can be used as time markers and provide a valuable history of potential environment impacting eruptions.
January 29, 2016. Erebus, Antartique :
Source : Mount Erebus Volcano Observatory