The 1914 eruption was the most powerful in twentieth-century Japan. Lava flows filled the narrow strait between the island and the mainland, turning it into a peninsula. The volcano had been dormant for over a century until 1914.[5] The 1914 eruption began on January 11. Almost all residents had left the island in the previous days, in response to several large earthquakes that warned them that an eruption was imminent. Initially, the eruption was very explosive, generating eruption columns and pyroclastic flows, but after a very large earthquake on January 13, 1914 which killed 35 people, it became effusive, generating a large lava flow.[5] Lava flows are rare in Japan—the high silica content of the magmas there mean that explosive eruptions are far more common[11]—but the lava flows at Sakurajima continued for months.[5]