Number 157 (Story #3), December 23, 1993 by Phillip F. Schewe and Ben Stein NEUTRINO TOMOGRAPHY OF THE EARTH'S INTERIOR might be carried out soon with the DUMAND detector. The Deep Underwater Muon and Neutrino Detector, a series of strings of phototubes being installed now on the ocean bottom near Hawaii, does not observe neutrinos directly but rather the Cerenkov radiation emitted by muons (created by interactions between neutrinos and ordinary atoms) plowing through seawater. DUMAND is designed chiefly to study celestial sources of neutrinos, such as the Sun and supernovas, but, according to Berkeley scientist Chaincy Kuo, who spoke at the AGU meeting, variations in the observed neutrino flux may provide information about the Earth's internal structure (Science News, 18 Dec. 1993.)