The onset of frictional motion couples complex spatiotemporal dynamics of discrete contacts with different orders of magnitude at time and length scales.In order to reveal how these individual scales affect the frictional sliding,we establish a 2D multiscale spring-block model for the frictional sliding at an elastic slider-rigid interface.In this model,the rupture of frictional interface is described by three different types of locally microscopic motion: pinned,sliding and dislocated states.By using realistic boundary conditions,our numerical results can precisely reproduce the loading curves found in previous experiments.The precursor events,corresponding to a discrete sequence of rapid crack-like fronts propagating partially in the contact zone,can also be shown in our simulation.From the analysis of the microscopic motion,we characterize the evolution of the real contact area and the corresponding interface motion at the mesoscale level,and show that the evolution corresponds to four distinct and inter-related phases: detachment,fast and slow slip motion,as well as the rest of slip.These mesoscale behaviors are completely consistent with the existing experimental results and their physical mechanisms can be explained by the detailed information of the numerical simulation.The study is established on a bottom-up multiscale model which provides a comprehensive picture about the complex spatiotemporal dynamics of frictional sliding.