The hydrocarbon potential of the fore arc basins between the Siberut, Nias, and Simeulue islands and Sumatra was investigated in 2006 by the German Federal Geological Survey (BGR) with marinegeophysical and marine-geological techniques (cruises SO-189-1 and SO-189-2). The basin sediments are relatively coarse grained (in part, of volcanic origin). In most locations, they are too hard for the use of conventional heat flow probes, which penetrate only muddy to soft seafloor sediments.

To overcome this restriction and to measure in situ heat flow in hard-ground terrain of these fore arc basins, a new ‘hard-ground heat flow probe’ was developed and successfully employed at 10 stations during the SO-189 cruises. A conventional heat flow probe was operated at six additional stations. The development of the new probe initially was motivated by the observation of widespread ‘hard ground’ along the outer-arc high of the accretionary prism at the southern coast of Java in 1999 (marine cruise GINCO, leg SO-139-2 of BGR).