A sulfur miner was killed when volcanic activity at Mount Ijen in East Java released poisonous gas and triggered a 3-metre wave in a natural lake situated within the volcano’s crater on Friday afternoon.
The tremor occurred within the mountain at 12.30pm, resulting in toxic air and an isolated wave from the lake in the crater, kompas.com reported.
The wave that was formed in the wake of the volcanic activity recorded on Friday qualified as a tsunami, according to Indonesian tsunami expert Widjo Kongko.
He said a tsunami typically occurred when activities at the bottom of an ocean, gulf or lake disturbed the column of water on the surface.
“[A tsunami] may be triggered by an earthquake, landslide or volcanic activity. The phenomenon recorded in the lake within Mount Ijen’s crater is an example of a tsunami,” Widjo said on Monday.
He went on to say that the wave that occurred on Friday was known among experts as a seiche.
“Water oscillations or waves caused by tremors fall into the seiche category,” Widjo said.