Multiple band structures in $^{70}$Ge

High-spin states in $^{70}$Ge were studied using the $^{55}$Mn($^{18}$O,$p2n$) fusion-evaporation reaction at an energy of 50 MeV.  Prompt $\gamma$-$\gamma$ coincidences were measured using the Florida State University Compton-suppressed Ge array consisting of three Clover detectors and seven single-crystal detectors.  An investigation of these coincidences resulted in the addition of 31 new transitions and the rearrangement of four others in the $^{70}$Ge level scheme, providing a more complete picture of the high-spin decay pattern involving multiple band structures. Spins were assigned based on directional correlation of oriented nuclei ratios, which many times also led to unambiguous parity determinations based on the firm assignments for low-lying states made in previous work. Total Routhian surface calculations, along with the observed trends in the experimental kinematic moment of inertia with rotational frequency, support the multi-quasiparticle configurations of the various crossing bands proposed in recent studies. The high-spin excitation spectra predicted by previous shell-model calculations compare favorably with the experimental one determined from this study.