- The East Pacific Ridge (EPR) is a divergent tectonic plate boundary where the Pacific Plate and North American, Cocos, Nazca, and Antarctic plates are diverging with new crust being created. Eruptions have created both volcanic edifices (≥40m high) and thousands of seamounts (≥200m high, up to 900m high). There are two island systems, Galapagos Islands and Isla Marias Archipelago, but most volcanic systems are on the seafloor.
- The Pacific-Antarctic Ridge (PAR) is a divergent tectonic plate boundary where the Pacific Plate and Antarctic plates are diverging with new crust being created along the ridge. There are some sub-Antarctic volcanic islands along the PAR located close to Antarctica. These islands are to the south of New Zealand. One island is one of the only places on Earth where rocks from the mantle are exposed above sea level.
- An interesting intersection feature is the Louisville Ridge (LR) which stretches ~4300km northwest from the PAR. This is a long line of ~70# volcanic seamounts believed to have formed by the Pacific Plate moving across a magma upwelling called the Louisville hotspot.
