He enjoyed going for long skiing tours in the mountains in Stavanger, when he was young, and several times he crossed Trollgaren in Ryfylke, this marvelous moraine that is appropriate to its name.

He wondered how it was formed, and was told by the local farmer that it was really Trolls that had set up the meandering fence of huge boulders, far above the tree line.

He was responsible for the geological education of more than 30 year groups of students, and he continued to participate in academic society until autumn 2011, when he had developed cancer and was in poor health.

Andersen's first expedition to the South Pole came in a period of small Norwegian interest in the Antarctic after the great achievements of Roald Amundsen in 1911–1912.

[1] During the fieldworks for his Master's thesis "Om isens tilbaketrekking i området mellom Lysefjorden og Jøsenfjorden i Ryfylke" (On the glacial retreat in the area between the Lysefjorden and Jøsenfjorden in Ryfylke), with Werner Werenskiold as advisor, he found among other things that Trollgaren was a moraine, and that it was formed in the early Holocene, probably about 11,000 years ago.

Andersen discovered an until then unknown area of Rogaland containing rock of the Cambrian-Silurian age on a much lower level than the surrounding bedrock.

During this fieldwork in the Lysefjord area, Andersen developed a method for determination of climatic conditions from the reconstruction of Ice Age glaciers which is still used by geologists and geographers.

He accompanied a party of scientists doing field studies in Chile in 1991–99, and in New Zealand in 2000–08, led by the American Quaternary geologist Professor George H. Denton of the University of Maine.

There he also discussed the continuation of his Norwegian fieldwork, and in September–October joined a joint Norwegian-US exploratory expedition to Lysefjord led by Jan Mangerud and George Denton which investigated the application of a new dating method to the moraines he charted in the 1950s for his Master's.