 |
The history of Mt. Iwate's eruptions |
|
| |
|
 |
A picture of Mt. Iwate drawn in the Edo Period. You can see that it is erupting on its western side. (From the collection of the Morioka Central Community Center) |
 |
Mt. Iwate's historical eruptions |
1686
(Edo Period) |
A lot of ash fell, and there was a muddy flood of the Kitakami River. |
1687
(Edo Period) |
Earthquakes occurred continuously from the daytime into the night, and there were mud and lava flows. |
1732
(Edo Period) |
Lots of lava was ejected, creating the "Yakehashiri". |
1919
(Taisho Period) |
A phreatic eruption produced a layer of ash about 10cm thick. |
(Source: 2000 "Iwate Yearbook", Iwate Nippo Co., Ltd.) |
| Mt. Iwate is thought to have been formed 700,000 years ago. It has erupted many times. In the Jomon Period (12,000~2,000 years ago) Mt. Iwate started erupting separately in its eastern and western sides. The oldest eruption on record is a very large one that occurred in 1686. Since then, there have been four eruptions, the last one in 1919. It is thought that the 1732 eruption ejected lots of lava and produced the "Yakehashiri". At that time volcanic ash also fell as far away as Morioka. In the 270 years since then, no magma eruptions have occurred. The last eruption was the phreatic eruption of 1919. No eruptions have occurred since that time, but volcanic gas (steam blowing out of the mountain) is sometimes released. (Source: Geological Features of Mt. Iwate, Board of Education, Takizawa Village, Iwate Prefecture) |
