I don't remember is @claus or anyone else had posted this, but here's a screenshot of an ice drilling operation I came across.
Gee... the people look just like those penguins in the other screenshot!
And here's a crack from lava/hot mud from the volcano wwwaaaaayyyyy up and to the left (off this map). When you zoom in you can see inside the crack is that muddy brown (not dark shadow) and where the ice on either side is not smooth, you can make out a faint brownish tint where it's trying to push up through the ice (or where the ice is melting over it). You can also see the original crack in the ice which is running in a nearly perfect straight line. The "lava crack" kind of deviates from it in places. No seals here!
EDIT: Here's the link (sorry): https://www.tomnod.com/campaign/antarctica_pilot_2/map/1g3kxgyt