Geologist Trevor Williams, of Columbia University's Lamont-Doherty Earth Observatory, has spent six weeks at Antarctica's McMurdo Station, taking part in a study of the sea-floor sediments beneath the Ross Ice Shelf. The results could aid our understanding of climate change. Williams has filed reports here throughout the project. Listen to him live from the bottom of Earth here.

At the surface, the loggers monitor the cable tension, the depth of the logging tool and the data being sent up the cable—images of rocks and fractures in the borehole wall, records of seismic waves and so on. There are moments of panic when the cable tension goes up and the logging tool has to be unstuck, but mostly it's the long haul. We logged for five days, with occasional troubleshooting and little sleep, but the effort is worthwhile: The data will tell us about the sediment types down the hole, crustal stresses and the structure of the sediment layers, and will be compiled with information from the recovered cores.

Volcanic Geography
In addition to providing a scenic backdrop for our work here, the 12,448-ft.-tall Mt. Erebus (pictured at top right) also played a role in deciding on the actual location of the drill site. To study the history of the Ross Ice Shelf, we needed thick layers of sediment (for the detail) with few instances of erosion (for a continuous record, without gaps). But whenever the ice sheets advance, they typically scrape away the sediments layed down in the previous advance, so suitable locations are few and far between.

The Ross Island volcanoes built up over the last 5 million years, and weighed down the Earth's crust to form a moat around the island— deep enough for the sediments to accumulate in a thick pile without being eroded. Plus, there's the added benefit of learning about past volcanic eruptions, from the ashes and pumice found in the core. Mt. Erebus is one of only three volcanoes in the world with a permanent lava lake (pictured at right, middle) and, sitting just 25 miles from McMurdo research station, the easiest to study (the others are Nyiragongo in the Democratic Republic of Congo and Erta 'Ale in Ethiopia, both requiring armed escorts to visit).

From a camp near the summit of Mt. Erebus, a team of scientists from New Mexico Tech and the University of Cambridge are monitoring the volcano's present activity—deploying cameras, seismometers, tilt-meters and gas monitoring equipment. This year, Erebus has been gently puffing away, releasing about 1900 tons of carbon dioxide and other gases every day, compared with last year, when it threw up lava bombs the size of a small car.

Antarctic Possibilities
Our ANDRILL project and the volcano observatory are only two of the science projects based at McMurdo (several funded by the National Science Foundation): There are studies of wildlife under the sea ice, the ancient landscapes of the Dry Valleys, radar surveys across the ice sheet, studies from balloons like BLAST launched high into the stratosphere and many more.

In addition to science, the National Science Foundation runs the Antarctic Artists and Writers Program, enabling artworks such as Lita Albuqerque's magnificent "Stellar Axis" (pictured at bottom right).

If the weather cooperates, I'll be flying north to New Zealand tomorrow, and my trip to Anarctica will draw to a close. Many thanks for joining me; I hope you've enjoyed the adventure to the bottom of Earth as much as I have. —Trevor Williams

EARLIER FROM ANTARCTICA: The Great Rig in the Sky (Log #5), Open-Water Armageddon (Log #4), The Science of Ice (Log #3), First Days on the Ice (Log #2), Journey to the Bottom of the Earth (Log #1)