Segmentation fault in muography experiment

Hello, for the purposes of a muography simulation I have created the geometry of a volcano in G4 (8 km long, 8 km wide, 2 km high, ~ 9000 voxels in total). A “world” equal or slightly bigger than these dimensions will return a segmentation fault on start and Qt will crash immediately without visualizing the structure. World should be substantially smaller (a few hundreds of meters in all dimensions) in order the geometry to visualize in Qt, no matter the size of the volcano. Is there a way to go around this problem, so that my volcano fits in a world larger than the volcano itself? Note that I am running G4 on a virtual machine (with less RAM resources available than the host computer).
Thanks in advance, Dinn.