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Fig. 1 | Earth, Planets and Space

Fig. 1

From: Possible slow slip event beneath the Kii Peninsula, southwest Japan, inferred from historical tilt records in 1973

Fig. 1

Observed tilt records. a Map of the study area and observed tilt change. The green arrow indicates the tilt change at the Kishu observatory indicated by a triangle. The inset shows a map of Japan with a rectangle indicating the location of the study area where the Philippine Sea plate (PH) is subducting beneath the Amurian plate (AM). Black lines indicate the plate boundaries. b Picture of original bromide papers. c Original time series of ground tilt in the (top) N57W and (bottom) N33E directions from November 19 to December 10 in 1973. Each letter indicates a temporal connection of time series. Arrows denote the timing of two earthquakes with JMA magnitudes of 5.9 and 5.7. The recording speed was about 0.2 cm/h, and 4.8 cm in the horizontal measure corresponds to ~ 1 day. Note that the record obtained during the first ~ 1 cm of each bromide paper corresponds to the stuck region in circling the bromide paper. d Digitized time series. Black lines indicate the tilt change in the (top) N57W and (bottom) N33E directions and blue lines indicate the theoretical tide corresponding to both directions. Solid grey vertical lines indicate the start and end of each bromide paper. The solid colored squares are the period when two lines are overlapped in the original bromide records, one of which actually means a record in the period shown by dotted colored squares

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