Considering seismic ambient noise as a tool for geophysical research, the spatial and temporal characteristics of the noise itself are of a great interest. Characterization of energy and frequency distributions of the microseisms is an important stage of the research. The review considers the main mechanisms of generation of microseismic oscillations in a wide frequency range, including primary and secondary microseisms (0.05–0.3 Hz), low-frequency oscillations (0.2–50 mHz), high-frequency oscillations (2–60 Hz), lake microseisms (0.5–2 Hz). The paper also describes the most popular techniques used for processing and analyzing a continuous data of seismic ambient noise; a wide range of geophysical problems was demonstrated, which use the results of seismic monitoring.