Pacific Ocean To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately to the southeast of Hawaii is computed, and if the region is more than above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures
East Pacific Rise Peru–Chile Trench along the coast of southern Chile. The southern extension of the East Pacific Rise (called the Pacific-Antarctic Ridge) merges with the Southeast Indian Ridge at the Macquarie Triple Junction south of New Zealand. Parts of the East Pacific Rise have oblique spreading, that is seafloor spreading that is not orthogonal to the nearest ridge segment. Along the East Pacific Rise the hydrothermal vents called black smokers were first discovered and have been extensively studied. These vents are forming volcanogenic massive sulfide ore deposits on the ocean floor. Many strange deep-water creatures have been found here. The southern stretch