Fig. 3From: Real-time crustal monitoring system of Japanese Islands based on spatio-temporal seismic velocity variationSchematic representation of estimating temporal velocity variation by a ARM and b SRM. N and M are the stacking periods, in days, for the current and reference trace, respectively. In ARM (panel a), the data period for the new current trace is moved by 1 day while the data period of the reference trace is fixed. In SRM (panel b), the data periods for the reference and current traces are both moved by 1 day, then stretching interpolation is applied for the entire length of the reference trace. In SRM, the current trace data always overlap with the reference traceBack to article page