Maui, a picturesque island in the Hawaiian archipelago, owes its unique landscape to a history of volcanic activity. Formed by lava flows over millions of years, this ongoing process prompts questions about its past eruptions and future potential.
Maui’s Most Recent Eruption
Maui’s most recent volcanic eruption occurred from Haleakalā volcano’s Southwest Rift Zone. While historical accounts initially suggested the eruption took place around 1790, radiocarbon dating indicates that the last eruption likely occurred sometime between 1480 and 1600 AD.
This eruption produced lava flows that reached the ocean, significantly altering the island’s southwestern coastline. These flows are still visible today at Cape Kīnaʻu, located between ʻĀhihi Bay and La Perouse Bay. Characteristic of shield volcanoes, these eruptions typically involve fluid lava flows rather than explosive events.
Haleakalā’s Current Status
Haleakalā, the dominant volcano forming more than 75% of Maui, is currently classified as dormant, not extinct. This means it retains the potential for future activity despite no recent eruptions. The USGS Hawaiian Volcano Observatory (HVO) actively monitors Haleakalā for signs of renewed unrest.
Monitoring efforts include continuous GPS instruments and seismometers near the volcano’s summit and rift zones. These tools track ground deformation and seismic activity, which can be indicators of magma movement beneath the surface. Although there have been no significant signs of unrest like increased earthquakes or ground swelling in recent decades, scientists anticipate that Haleakalā will erupt again in the future. The most probable locations for future eruptions are along its southwest and east rift zones, where past activity has been concentrated.
A Glimpse into Maui’s Volcanic Past
Maui’s formation is a complex geological story, born from the activity of multiple volcanoes. The island is primarily composed of two massive shield volcanoes: Haleakalā (East Maui Volcano) and the older West Maui Mountains (Mauna Kahalawai). These volcanic structures grew from the ocean floor, with their lava flows eventually overlapping to create a single landmass.
The western volcano, Mauna Kahalawai, is considerably older and has experienced extensive erosion, shaping its rugged peaks and valleys. Its volcanic activity is prehistoric, having ceased long before human habitation. Haleakalā has a more recent history of eruptions, with at least ten recorded over the past 1,000 years. This volcanic past has sculpted Maui into the island seen today, characterized by diverse landscapes ranging from barren lava fields to lush, fertile valleys.