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Fig. 5 | Earth, Planets and Space

Fig. 5

From: Changes in the b value in and around the focal areas of the M6.9 and M6.8 earthquakes off the coast of Miyagi prefecture, Japan, in 2021

Fig. 5

Time series of b values. a Map showing the regions “A” and “B” considered in b, c. Stars indicate the epicenters of the M6.9 March 20 earthquake, the M5.8 April 18 earthquake, and the M6.8 May 1 earthquake. Other symbols are the same as in Fig. 1. b Plot of b values as a function of time, as obtained from seismicity data along the plate boundary for the period since 2018. We used a moving window approach, whereby the window covered 100 events. The uncertainty estimates are according to Shi and Bolt (1982). Thick vertical dashed lines indicate moment of the M6.9 and M6.8 earthquakes. c Zoom-in figure for the period from immediately before the 2021 M6.9 earthquake to May 15, 2021. Thin vertical dashed lines show March 21, April 1, 11, and 21, and May 1 and 11

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