Fig. 1
From: Seismic velocity decrease and recovery related to earthquake swarms in a geothermal area
(a) Study area index map. The red inverted triangle marks the location of a seismic station operated by the JMA (OITA2), while blue triangles show stations operated by NIED/Hi-net. A relocated epicenter distribution of earthquakes in the rectangular area is shown in (b). Symbol colors indicate the sequence of the earthquakes in this region, counting from June 1, 2007. The fault mechanism of the largest earthquake during the episode is shown above. (c) The bottom left panel shows a time-magnitude plot of the earthquake activity in the rectangular area. (d) Hypocenter depths along the A–B profile are shown in the bottom right panel.