Iwate volcano

complex volcano 2041 m / 6,696 ft
Honshu, Japan, 39.85°N / 141°E
Current status: normal or dormant (1 out of 5)

Iwate volcano is a symmetrical stratovolcano in northern Honshu, Japan, 20 km northwest of Morioka City.
It consists of 2 cones, the older western Nishi-Iwate and the younger eastern summit Higashi-Iwate. The older volcano to the west is truncated by a caldera that resulted from repeated collapse.
The caldera contains a central cone with a 500 m wide crater containing a lake and is breached by a narrow gorge to the NW.
Volcanic activity migrated to the east and built Yakushi-dake, the young, mainly basaltic summit cone of Higashi-Iwate. Yakushi-dake contains a 500 m wide crater and partly buries the eastern rim of the caldera. It is the vent of most recent activity including a lava flow from the eruption in 1732 that traveled down the NE flank.
The last historic activity was a small phreatic eruption from O-jigokudani on the W side of the Onigajo caldera. The eruption caused mudflows.
There are uncertain reports about activity in July 1934.

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Typical eruption style: explosive
Iwate volcano eruptions: 1934 (?), 1919, 1732, (reported 1719 eruption was in 1732), 1689 (?), 1687, 1686
Radiocarbon- & tephrochronology dated: 1450 ± 100, 1300 ± 50, 150 AD (?), 350 BC (?), 450 BC (?), 1150 BC (?), 1250 BC (?), 1500 BC ± 300, 1650 BC (?), 2000 BC (?), 2050 BC ± 200, 2950 BC ± 50, 3050 BC (?), 3250 BC ± 500, 3750 BC ± 100, 4350 BC ± 500, 4450 BC ± 500, 4850 BC ± 50, 4900 BC ± 100, 5650 BC ± 50, 6300 BC ± 100, 6450 BC ± 1000

No recent earthquakes
TimeMag. / DepthDistance/Location

Background

The western and older volcano Nishi-Iwate contains an oval-shaped 1.8 x 3 km caldera. Nishi-Iwate volcano begin growing about 700,000 years ago and suffered repeated (at least 7) collapse during the past 230,000 years, most recently between 739 and 1615 AD.

1998 magma intrusion event
There was no eruption, but from February to September 1998, dike intrusions were observed geodetically and seismologically at Iwate volcano. Magma commenced rising beneath the eastern basaltic cone and later migrated laterally westward. ...more

See also: Sentinel hub | Landsat 8
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