火か山ざん性せい微び動どう

noun

volcanic tremor

Technical term in volcanology for continuous seismic vibrations associated with magma movement.

• 火か山ざん性せい微び動どうが観かん測そくされたため、噴ふん火か警けい戒かいレベルが引ひき上あげられた。

  Because volcanic tremors were observed, the volcanic alert level was raised.