Multiple underground nuclear explosions may trigger the rupture of seismic faults and mimic a natural earthquake. Moreover, multiple nuclear explosions can be spatially arranged (on a vertical line for instance) and temporally synchronized in order to reduce significantly the P-waves (except inside both spherical cones along the vertical line arrangement).A Specific Magnitude Budget, with the relevant elementary approximations, is relatively enough accurate to compare unambiguously the energy of the stress drop over the fault rupture and the energy of the radiated seismic waves.Indeed, for the largest natural earthquakes precisely recorded ($6.9 leq M_wleq 7.3$), we define very conservatively their average seismic radiation efficiency to $0.25$. It follows from that definition, the natural seismic radiation efficiency ranges between $0.113$ and $0.520$ around the average $0.269$ (the natural Specific Magnitude Budget range between $Delta_{nat}^{min} M_Z=-0.630$ and $Delta_{nat}^{max} M_Z=-0.189$ around the average $Delta_{nat}^{mean} M_Z=-0.380$).On the other hand, the nuclear seismic radiation efficiency ranges between $1.185$ and $1~113$ around the average $81.9$ (the nuclear Specific Magnitude Budget range between $Delta^{min}_{nuc} M_Z=0.049$ and $Delta^{max}_{nuc} M_Z=2.031$ around the average $Delta_{nuc}^{mean} M_Z=1.275$).In practice, the natural seismic radiation efficiency is always $2.278times$ times smaller than the nuclear seismic radiation efficiency (an artificial gap of the Specific Magnitude Budget $Delta_{gap} M_Z=0.238$ is found). Indeed, to provoke a more powerful stress drop over the fault rupture with multiple underground explosions, an accurate information about the future epicenters should be known which is impossible in practice. Lowering too much the energy of the multiple underground nuclear explosions would also increase the risk of not triggering at all the rupture of a seismic fault.