It emerged from the ocean about 300,000 years ago and is one of the five volcanoes that make up the island. Approximately 40 to 70 million years ago, Hawaii's 137 islands began to form. Each island in the archipelago originated from multiple underwater volcanic eruptions. For additional information on Hualalai Volcano, visit the USGS Hawaiian Volcano Observatory (Hualalai) page.
No magma-related seismicity or soil deformation has been detected recently in Hualalai, making it difficult to say if and when the next eruption could occur. Although 200 years have passed since the last Hualalai eruption, it is almost certain that it will erupt again. During this period, no microearthquake swarms or harmonic tremors (both indicative of magma migration) have been recorded, although Hualalai experiences several magnitude 4 earthquakes each year. Lava flows represent by far the greatest danger in a possible future Hualalai eruption, because although explosive pyroclastic eruptions have occurred during the Holocene epoch (the last 10,000 years), they are relatively rare and cover only limited parts of the volcano.
Alkaline eruptions in Hualalai have generally been much less explosive than those at neighboring Kohala and Mauna Kea volcanoes.
