Complex sentence: The summit and the crater are located entirely in Chile, slightly over to the south west of the international borders, it is about wide and contains a by crater lake, Licancabur Lake, which is ice-covered most of the year.
Split into simpler sentences: The summit and the crater are located entirely in Chile, slightly over to the southwest of the international borders. It is about wide and contains Licancabur Lake, a by crater lake which is ice-covered most of the year.