https://unilib.phaidrabg.rs/o:2663 eng 2022 Nova Science Publishers, Inc. application/pdf 18244047 bytes Kostić, Srđan Vasović, Nebojša Todorović, Kristina mean-field apprpximation, random and colored noise, earthquake, groundwater level dynamics, slope stability, excitability, bifurcation All rights reserved “Advances in Engineering Research“, Chapter 5, Ed.: Victoria M. Petrova 50 Abstract - Noise represents a regular companion of almost all natural processes, including earthquakes, landslides and similar, and it exists permanently unrelated to the activity of contemporary geodynamical processes. For example, background seismic noise is recorded regardless of the seismic activity within the monitormg area. However, during the seismic event, noise is also the constituent part of the recorded signal, and it is commonly isolated by applying different processing techniques, i.e., different types of filtering. From the purely theoretical viewpoint, one could single out two major types of noise: random (white) and colored (correlated) noise, with the white noise as the most common type of noise in natural processes. In general, regardless of the type of noise, its main characteristics are extremely small amplitude and high frequency. In most of the cases, due to its small amplitude, noise does not have any significant effect on the triggering, duration and properties of the main event, e.g., landslide moyement or seismic fault displacement. Nevertheless, there are certain scenarios when noise could have a crucial role in the initiation of the instability and its further qualitative properties. Focus on these scenarios is presented in this chapter. After providing theoretical framework on the noise and methods of nonlinear dynamics used to study the noise, i.e., the mean-field approximation in the first place, the largest part of the chapter is concentrated on the influence of different types of noise on the triggering of earthquake fault movement and groundwater level dynamics. Four illustrative examples are studied in detail: effect of the white background noise and impact of the colored noise on the earthquake nucleation, the correlated noise as the constituent part of the model of groundwater level dymmics and the effect of noise on the dynamics of excitable systems. Existence of noise in all three examined cases is firstly proved for the real-world examples, i.e., for the recorded natural signals. In case of earthquake nucleation, it is shown that when stress accumulation along the fault reaches critical values (near the bifurcation) even small-amplitude oscillations (background seismic noise) could be sufficient for triggering the instability. On the other hand, when it comes to the influence of colored noise, it is shown that the increase of correlation time and coupling strength prevents the onset of seismic fault motion, indicating the predominant effect of random (white) seismic noise. Regarding the groundwater level dynamics, results presented in this chapter indicate that only models with the included colored noise could realistically mimic the real groundwater level oscillations. As for the excitable systems, we analyze conditions for which the influence of noise triggers the activation process. M14 prihvaćeno na 15. sednici Matičnog odbora za uređenje, zaštitu i korišćenje zemljišta, vode i vazduha, 30.01.2023. godine. The Effect of Noise on Dynamics of Natural Processes: A Review of Methodology and Engineering Applications info:eu-repo/semantics/bookPart