The Samoan islands result geologically from volcanism, originating with the Samoa hotspot, which probably results from a mantle plume. While all of the islands have volcanic origins, only Savai'i, the westernmost island in Samoa, remains volcanically active, with the most recent eruptions at Mt Matavanu (1905-1911), Mata o le Afi (1902) and Mauga Afi (1725). The highest point in Samoa is Mt Silisili, at 1858 m (6,096 ft). The Saleaula lava fields situated on the central north coast of Savai'i result from the Mt Matavanu eruptions, which left 50 km2 (20 sq mi) of solidified lava.