A joint Belgian-Chilean biological mission, conducted by Prof. H. Dumont of the Department of Morphology, Systematics and Ecology of the Gent University (Belgium), visited Easter Island in the summer of 1990. During this expedition, which lasted a few weeks, coring operations took place in the crater lake of Rano Raraku in view of biological and palaeoecological research.
Boven, A.; DeDapper, M.; DePaepe, P.; Langohr, R.; and Pasteels, P.
"Evolution of the Southwestern Edge of the Poike Volcano, Easter Island,"
Rapa Nui Journal: Journal of the Easter Island Foundation: Vol. 11
, Article 6.
Available at: https://kahualike.manoa.hawaii.edu/rnj/vol11/iss2/6