2016 Volume 67 Issue 6 Pages 209-215
Towada volcano is an active volcano located in the northern part of the Northeast Japan arc. K–Ar ages of lavas exposed at the Towada caldera wall were determined to establish a detailed eruptive history during the pre-caldera stage of Towada volcano. The obtained K–Ar ages were 0.26 ± 0.07 and 0.13 ± 0.06 Ma for Ohanabeyama Lava and 0.09 ± 0.06 and 0.09 ± 0.06 Ma for Hakka Lava and Pyroclastics. Although these K–Ar ages have large error ranges, they are consistent with stratigraphy. Distal tephra stratigraphy at the Kamikita Plain suggests that the main volcanic activity of Towada volcano have started at no earlier than ca.0.22 Ma. The newly obtained K–Ar ages of proximal lavas are consistent with the onset age of the volcanic activity estimated from the distal tephra stratigraphy.