History of Unzen (Japanese)

2 - 2

History of the growth of Unzen Volcano

Top of Part 2

We can speculate upon

the history of

the growth of

Unzen Volcano

from the detailed study

of the geology

in the Shimabara Peninsula.

Geology of Unzen Volcano and the surrounding area (the Shimabara Peninsula)

History of the growth of Unzen Volcano

Studying the chronology

of the above geological map,

we can guess the history

of the growth of Unzen Volcano

as follows:

The volcanic activities of

Unzen Volcano

started with the eruption at

the Hayasaki Peninsula of

the southern end of

the Shimabara Peninsula

about 4 million years ago.

This is called

Hayasaki Stage.

Thereafter, the eruption center

moved gradually to

the north, and reached

the present stage

via Minami-Shimabara Stage

and then

Unzen Stage.

The following figure

is the S-N cross section

of the Shimabara Peninsula.