火口

かこう

crater (of a volcano)

JLPT N2

Character Breakdown

Meaning and Usage

"火口" (かこう) specifically refers to the crater of a volcano, the opening through which lava, ash, and gases are emitted during an eruption. It is a common geological term used in both scientific and everyday contexts when discussing volcanoes.

Common Contexts

You will often hear "火口" in news reports about volcanic activity, in travel guides describing volcanic sites, or in educational materials about geology.

Collocations and Patterns

  • 火口の周り (around the crater): used to describe the area surrounding the crater, often mentioning lava or rocks.
  • 火口から煙が出る (smoke comes out of the crater): describing volcanic activity.
  • 火口付近 (near the crater): used to warn about danger or restricted areas.

Register and Nuance

"火口" is a neutral, standard term appropriate for formal and informal contexts. It is a technical term but widely understood by the general public in Japan.

Common Learner Notes

Learners sometimes confuse "火口" with "火山" (volcano) or "噴火口" (vent). "火口" specifically means the crater itself, not the entire volcano or just the vent. Remember that "火口" focuses on the crater's physical depression at the volcano's summit or side.

Example Sentences

かこうのまわりにはようがんがかたまっている。

Lava has solidified around the crater.

かこうからけむりがたちのぼっているのがみえる。

You can see smoke rising from the crater.

かこうふきんはきけんなのでちかづかないでください。

The area near the crater is dangerous, so please do not approach.