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Off from LEH to
a place called Nausea Knob. Here is a view of Upper Erebus Hut on our way. The things sticking out of the mountain on the left hand
side are installations at a site called E1. Similar to LEH and Nausea Knob, E1 got a new broadband seismic station this year. The Erebus
crater camera also comes through this point on its way back to McMurdo. It's more or less right on the crater rim but unfortunately there
was no urgent work for us to do at this site today. Then, the day after I got back I got an email from the group asking if we could
get an extra hour to hike up to the camera to clear off the rime ice that had formed on the view! They didn't know that I had
already been up there (helo schedules are highly variable and dependent on the weather). Dang! But still, Nausea Knob was still pretty darn high up. The views here were stratospheric.
The seismic
station at Nausea Knob. This place was named by Phil Kyle because when the winds are right (or wrong), the plume will blow down here
and cause you to feel nauseous. There are lots of nasty gases, acids, heavy metals, etc. in the Erebus plume, and breathing it is
not pleasant. But again the weather today was primo and we didn't have to deal with that. The tower on the left is the
wind generator and the tower on the right is the antenna mast.
Here is the
antenna mast as we found it. Tons of rime ice built up on the mast and the guy wires, but none on the antenna. This site had been experiencing
dropouts of all its signals, and the most likely theory was that rime ice buildup either here or
at the Truncated Cones site (where the signal is repeated to McMurdo) was responsible for signal attenuation. But no antenna rime problem here.
The wind
generator at NKB (station ID for Nausea Knob), also with a full load of rime. This stuff forms on the windward edges of structures (or rocks, etc.) during moist, cold storms.
The water droplets contained in the wind will be cooled past their freezing point, but they have a hard time freezing if there's no 'nucleus' on which to form ice.
But once the supercooled water hits a particle or surface, it will instantly freeze and build up an ice layer. Then, the structure of these ice crystals
gives the next bit of water a place to freeze to. So you get these ice buildups all over the place after storms. I've even had some
form at the Arrival Heights hut on various cables and wires. But here, you're in the clouds and the wind really howls. So, this is
the perfect recipe for rime. And this year has been extraordinarily bad for rime ice. Well, bad in the sense that it interferes with
the seismic systems. It builds up on solar panels, jams up wind generators, and can interfere with the antennas' signal strength. But it's actually
quite pretty.
Although the antenna
was fine here, we decided to clean off the rime from the guy wires, boxes, and solar panels as best we could. So here are Chuck
and George doing just that.
Me, with
a wedge of the stuff that came off a cable.
I also had a look at the
various devices inside the instrument box while I was here to see if there were any apparent problems. Nope.
And
the seismometer box.
A view looking
out from Nausea Knob. The rocks here were all obscured by rime ice. This place must get absolutely nailed during storms.
The view
looking north toward Mount Bird, an extinct volcano on the northern tip of Ross Island. Out there somewhere below the clouds
is the great iceberg menace: B-15. This thing is larger than Rhode Island and has gotten stuck in an unlucky place at the inlet
to McMurdo Sound. It has disrupted the natural flow of things around here and has caused all sorts of problems the past couple years.
On the way
back to the helo, I saw these guys standing around poking at the ground. ????
Turns out, we had
landed right on a lava bomb. All around you could see these little ring-like shapes covered in snow where hot lava bombs
had landed and splattered. Coming in with a helo to a snowy landing zone it is hard to see exactly where you're going to land. So the pilot touched down right
on a lava bomb and although he wasn't 100% happy with the footing, he decided it was OK to park. And it was. On the way back they started jabbing
at the ground and uncovered some gnarly hardened lava.
Here's Chuck
with a bit of the lava bomb. You dig down a bit and then you can put your hand in and sort of peel back a chunk of the stuff. The outside
is weathered and crusty, but the inside is almost hollow, where the lava had dripped down and hardened like taffy. So you pull
up a bit of this and turn it over...and here is this amazing piece of VERY delicate rock with fine strands and tendrils protruding out.
This was incredible - digging in the ground and pulling out something like this. Chuck obviously thought so too. Actually, there
were a lot of ooo's and ahhh's coming out from the bunch of us. George and I are rookies here, so of course we were amazed. But even
the other guys, who had been all over down here, were giddy over this. It was just that cool!
A close up
of a lava bomb chunk. The structure here is remarkably fine.....so fragile that it's nearly impossible to
touch without breaking a little piece off. If you even breathe on this stuff it goes "tink" and breaks. It's crazy to find something
this delicate in such a harsh place like the top of Mount Erebus.
The helo guys
picked up a couple chunks and stuck them inside. I grabbed a couple small pieces too. This was one of them, which now sits in my office
in Crary. It was impossible to get it back to station completely intact, but it survived the helo ride OK I guess. It's still darn impressive
to look at.
Another
chunk.
The blades
of the 212. Helicopters are very photogenic. Many good angles from which one can take a reasonable picture!
The pilot
decided to position the helo before we took off. Not sure why, but I'm sure he knew exactly what he was doing. So here's a
video of the 212 picking up a bit and putting back down a short ways away. (.avi file)