Basalt lava erupts from Pu‘u ‘Ō‘ō cone

The largest known effusive eruptions on Earth have paved hundreds to thousands of square kilometers of its surface with basaltic lava. Erupting hundreds of lava flows over a period of a few million years, scientists refer to the resulting deposits as flood basalt and the areas covered as plateau basalt. One such area covered with flood basalt is the Columbia Plateau region of eastern Washington and Oregon. Between about 17 and 14 million years ago, a series of eruptions with a total volume more than 175 million km³ covered an area of about 165,000 km². Even more voluminous plateau basalts are located in South America, South Africa, and India.