The eruption of Akita-Komagatake in Sep 1970 (source: www.qsr.mlit.go.jp)
Akita-Komaga-take volcano is an active volcano in northern Honshu. It is located 10 km east of Tazawa Lake, near the border of Akita and Iwate prefectures, and forms the southern extremity of the Towada-Hachimantai National Park.
The volcano consists of a main edifice cut by 2 calderas that formed after 2 large explosive eruptions between 11,600 and 13,500 years ago. The calderas are partially filled by younger cones. Historic activity consists of small eruptions from cones and fissure vents inside the southern caldera.
It is suspected that Akita-Komaga-take's eruptions are often not preceded by much seismic activity, as was the case during the last eruption, in 1970.
1970-71: strombolian activity and lava flow
1932, 1902, 1890-91, 1100? (TC), 807 AD
Radiocarbon (RC) and Tephrochronology (TC) dated:
400 AD ± 500 (TC), 50 BC ± 200 (RC), 200 BC ± 200 (RC), 350 BC ± 200 (RC), 1450 BC ± 50 (RC), 5950 BC ± 200 (RC), 6150 BC ± 300 (RC), 6350 BC ± 200 (RC), 7100 BC ± 1000 (TC), 7850 BC ± 200 (RC), 8300 BC ± 300 (TC), 8800 BC ± 300 (TC)
Typical eruption style
explosive & effusive
The larger southern caldera of Akita-Komaga-take is NE-SW elongated and 1.5 x 3 km wide. It contains the younger cones Me-dake and Ko-dake in the NW corner, the Komaga-take cone (also known as Omae-dake or Oname-dake) in the center, and the small pond Amida-ike. Its floor dips to the SW where it is drained by a narrow gap. Komaga-take has erupted lava flows to the north and east. It contains a 100-m-wide summit crater.
The adjacent smaller northern caldera is 1.2 km wide, more circular and widely breached to the NE. It contains a cone forming the highest point of the volcano.
