Description:
<jats:p> <jats:italic>KeyGraph, </jats:italic>a document–indexing (keyword–extraction) algorithm, is applied for a new purpose: Extracting active faults with risks of near–future large earthquakes from earthquake–sequences. This paper presents <jats:italic>KeyGraph</jats:italic> as an extractor of causalities from an event–sequence. This validates <jats:italic>KeyGraph</jats:italic> as a tool for showing <jats:italic>why</jats:italic> and <jats:italic>which</jats:italic> active faults are risky, as well as for showing why and which words abstract a document. The risky faults that are empirically obtained by <jats:italic>KeyGraph</jats:italic> correspond closely to real earthquake occurrences and seismologists’ risk estimation.</jats:p>