Fig. 2
From: Creating a digital database of tephra fallout distribution and frequency in Japan
(a) Location map of the 47 prefectural offices and 82 Quaternary volcanoes considered in this study, grouped into four regions (NE–W, NE–E, W, and SW) based on the geographical distribution of volcanoes. (b) Cumulative tephra fall thickness (mm) distribution map for the past ca. 330 kyr. Names in (b) show representative locations of prefectural offices. Bold Italic names show the two drill core sites. Orange dashed lines in (a) show the “volcanic front” after Sugimura and Ueda (1973)