Western Pacific Ocean A map of the Western Pacific Ocean showing the location of Marianas Trench and Kermadec Trench. Challenger Deep is the deepest point of the Marianas Trench. The Sirena Deep is the second-deepest part. SHARE IMAGE: Download Image: Full Size (1.45 MB) Photo By: U.S. Geological Survey VIRIN: 150607-O-ZZ999-772C.JPG Photo Gallery