South Arch volcanic field is an underwater volcanic field south of Hawaiʻi Island. It was active during the last 10,000 years, and covers an area of 35 by 50 kilometres (22 mi × 31 mi) at a depth of 4,950 metres (16,240 ft). Although the field is related to the Hawaiian hotspot, it does not appear to be a precursory volcano, but seems to have formed when the weight of the growing Hawaiian volcanoes caused the oceanic crust to buckle, opening up pathways for magma to ascend in front of the hotspot.