Hello from Camp E! Just thought I’d share with you some initial results from the geophysical acquisitions we’ve been doing. While bad weather got in the way of our camp move for a few days, it was no big hindrance to the progress of geophysics, which has mostly been about radar for now. We’ve currently got around 450 km of line data in the bank, allowing us to shed some light on the internal structure of the Larsen C ice shelf.

A radargram from the 2015 MIDAS field season, transmitted from Antarctica by satellite phone.

You can think of radar as being like a mobile X-ray. We send short pulses of radio wave energy into the ground, which are reflected from buried layers within the ice shelf and recorded by our equipment. Our system, a Sensors & Software PulseEKKO PRO, is towed on a sled behind a skidoo, at a speed of around 15 km/h - this gives us a datapoint every meter along the ice shelf surface! An example of our radar data is shown here, from one of our lines at the previous camp: the profile is about forty kilometers long, and shows the upper forty meters of ice structure. The strong lineations you can see are horizons within the ice shelf—but, interestingly, these are abruptly truncated. This gives the impression of a ‘hole’ within the radar data, which we are currently interpreting as a large body of homogeneous ice, distinct from the layered ice around it. Potentially this relates to old areas of melting, where the ice shelf has been restructured on refreezing? Either way, it will be interesting to see how this all maps up once we’re back in the comfort of the office!

Radar acquisitions are all but complete at this camp—Heidi is currently out with Al, filling in some gaps in one of our profiles. We’ll have a whole set more to do at our next camp, along with some seismic surveys using equipment scheduled to arrive on our resupply flight. Watch this space for more data!

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