A.T. Robertson Commentary Revelation 16:20

"And every island fled away, and the mountains were not found." — Revelation 16:20 (ASV)

Fled (εφυγεν). Second aorist active indicative of φευγω. Islands sometimes sink in the sea in earthquakes (6:14).

Were not found (ουχ ευρεθησαν). First aorist passive indicative of ευρισκω. See 20:11 for the same idea.