On the morning of March 30, 2000, the day before the eruption, cracks developed in roads and water supply pipes ruptured in this area. Water was sprayed from the pipes and the ground caved in. The Muroran Local Meteorological Office attributed the cracks, which extended westward, to crustal movements around Mt. Usu, and announced a volcanic warning. Water was gushing from the water supply pipes that had been joined with 7 cm long fittings but were displaced 10 cm from each other.
(Photographed by Tadahide Ui, 4.2.2000）
Analysis of ground levels before and after the eruption revealed that the ground in this area had been uplifted the most. This uplifting, caused by magma intrusion, led to the displacement of the water supply pipes. This implies that the construction machinery used to repair the pipes could “predict” the magma intrusion. Sharing information about such changes may help mitigate future volcanic eruption disasters.
The construction workers managed to escape the disaster narrowly along with another piece of heavy machinery.
