The chapter presents an overview of the results of a long-term study of the conditions of earthquake fociEarthquake foci formation and the ways to more reliably ensure seismic safety. The study was conducted primarily in the Baikal Rift Zone and Mongolia using a wide range of methods. They included: geological and geophysical survey of fault zoneFault zone segments; active monitoring of shear stress level in fault segmentsFault segment using man-made impacts with a falling weight, weak explosions, vibrations, and hydrowave injection of liquidsInjection of liquid; and numerical modeling. Analysis of the seismoacoustic and deformation responses of fault segments showed a high sensitivity of rock masses to dynamic impacts. The results of field studies confirmed that the occurrence of strong earthquakes in many cases is a consequence of multiple episodes of the failure of large-scale irregularities (asperities) in locked (trapped) fault segments. It was found that injection of liquids into the areas of frictional interaction of asperities in fault zones contributes to the decrease in shear resistance and the initiation of coseismic slip. Based on the results of a long-term study in the Baikal rift zone, it has been concluded that seismic gapsSeismic gap are confined to locked segments of seismically active faults. Injection of liquids through wells in combination with man-made vibration and hydraulic actions allows for managing the stress state of such segments. A method of reducing shear stresses in segments of fault zones was patented in the Russian Federation. The possibility of preventive stress relaxation in highly stressed fault segments was confirmed by new results. These results are related to the identification of sites of dangerous earthquake preparation in the Baikal Rift zone as well as to the development of regimes of periodic injection of limited volumes of solutions into selected fault segments. Solutions should be injected through deep vertical, inclined, and horizontal wells using advanced technologies that eliminate the hydraulic fracturingHydraulic fracturing effect. Further development of the considered method of increasing seismic safety and the transition to full-scale technology require the implementation of large-scale tests at geodynamic testing grounds within international cooperation.