sonic velocity substantially different from the liquid explosive alone in the form of a finely divided particulate solid the precise difference between the sonic velocity of the liquid constituents of the explosive and that of the ballistic modifier is not critical for purposes of the invention and suitable materials in accordance with that criterion are illustrated herein it is believed nevertheless that the mechanism involved in producing the superior properties of compositions in accordance with the invention is the formation of 34 hot spots 34 as the explosive shock wave propagates past the surfaces of the ballistic modifier due to the abrupt difference in the sonic velocity of the medium the resultant heat may sustain propagation of the explosion in diameters where absent the modifier it would be incapable of propagating unlike an active as opposed to an inert ballistic modifier however it does not adversely affect the stability and shock sensitivity of the explosive and unlike liquid and gaseous ballistic modifiers inert solids have been found to be capable of achieving the low critical diameters desirable for geological fracturing in accordance with the invention the inert ballistic modifier is preferably of an average particle size of a few microns generally there.