Figure 4
From: Nucleation process of the 2011 northern Nagano earthquake from nearby seismic observations
Space and time plots of seismicity for the “West” cluster. (a) Maps of detected events for different time windows. Colors indicate lapse time from the Tohoku-oki megathrust event. Pink star shows the M6.2 Northern Nagano earthquake. Gray rectangles indicate the ranges of 1 km NE along strike from the M6.2 earthquake. (b) Distance versus time plot along the fault strike of the M6.2 earthquake. Red open circles show events of the cluster plotted as a function of time and distance from the M6.2 mainshock epicenter. Light-blue dashed lines indicate an approximate earthquake migration direction (a rough estimation of the migration speed is written nearby). Size of circles scale with the corresponding events’ magnitude. Diamonds indicate small events for which was not possible to determine reliably magnitudes.
