Chikyū
... While the planned depth of the hole is significantly less than the Russian Kola Superdeep Borehole (which has already reached 12 km depth on land), the scientific results are expected to be much more interesting since the regions targeted by Chikyū include some of the most seismically-active regions of the world ... Other deep holes have been drilled by the drill ship JOIDES Resolution during the Deep Sea Drilling Project and the Ocean Drilling Program ...