How many letters does the top answer for “the branch of geology that studies volcanoes” have?

The most common answer is volcanology (11 letters).

Crossword clue: the branch of geology that studies volcanoes

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

volcanology 11 letters wn-def

the branch of geology that studies volcanoes

vulcanology 11 letters wn-def

the branch of geology that studies volcanoes

the branch of geology that studies earthquakes 60% similar → seismology