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Fig. 1 | Earth, Planets and Space

Fig. 1

From: Rupture process of the 2016 Kumamoto earthquake in relation to the thermal structure around Aso volcano

Fig. 1

Overview of the 2016 Kumamoto earthquake and magnitude of gradient of Bouguer gravity anomaly. a The yellow and white stars indicate the mainshock epicenter and the largest foreshock epicenter, respectively, determined by the JMA. Also shown are the focal mechanism and the moment-rate function of the mainshock determined in this study and aftershocks occurring in the first 3 days after the mainshock (black dots) determined by the JMA. Transparent black lines represent the Hinagu and Futagawa faults (headquarters for Earthquake Research Promotion, http://www.jishin.go.jp/main/index-e.html; last accessed on April 28, 2016). The red triangles show the active volcanoes. Inset map shows the Kyushu region, with a rectangle fringing the study area and the locations of active volcanoes as triangles. Thin lines denote the coastline and the boundaries of the prefectures. b The magnitude of horizontal gradient of Bouguer gravity anomaly (reduced for a density of 2.3 g/cm3) (Komazawa 2013). The strong horizontal gradient lines crossing Kyushu Island correspond to the Oita–Kumamoto Tectonic Line (OKTL). The blank triangles show the active volcanoes. The circular structure located in the center of OKTL is comparable with the Aso caldera. Overlaid blue contours represent the inverted slip distribution delimiting 1.14 m slip. Thin lines denote the coastline and the boundaries of the prefectures

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