起こる
おこる · okoru · JLPT N3 · verb-godan
to happen
起 = rise, get up: something rises up, so it happens. Things arise.
起 is the 'rise / get up' kanji, as in 起きる (to wake up). An event that 起こる is one that rises up. Careful: 怒る, to get angry, is also read okoru.
起 — 走 (run) + 己 (self/phonetic)
起 combines 走 'run/walk' as the meaning component with 己 as the phonetic component. The 走 element suggests movement of the body, giving the core sense of rising up or starting to move. From there it extended to meanings like 'get up,' 'begin,' and 'arise.'