Harima Iron Lava <Hyogo Prefecture> [Famous Stones of Japan]

HARIMA Iron Lava Stone

Harima Iron Lava

A time when the Japanese archipelago was not yet in its current location and was connected to the Eurasian continent by land.
82 million years ago, a volcano in Ako erupted and formed a caldera.
As time passes and the rock weathers, the caldera disappears and becomes a cauldron.
The remains of this mountain are concentric mountains, and traces of the lava can still be seen.
As the lava weathers and condenses repeatedly, it becomes more iron-rich and, when exposed to the Earth's magnetic field, becomes magnetic.
The Cauldron covers a wide area, stretching 21km east to west and 16km north to south, from Okayama Prefecture in the west to Tatsuno City in the east.
The fact that it was a cauldron was announced by AIST in 2016.
Volcanic eruptions reorganize the geology, making the ground stronger and more resistant to earthquakes and natural disasters.