A Century Later, the 1926 Mauna Loa Eruption: A Tale of Devastation and Resilience
The 1926 eruption of Mauna Loa, one of Hawaii's most active volcanoes, was a significant event in the state's history. It began on April 10, 1926, at around 3 a.m. HST, following two hours of elevated earthquake activity. The eruption started in the summit region and was visible across much of the island, with glow visible from as far as the U.S. Geological Survey (USGS) expedition led by Edward Wingate, who was mapping the summit region at the time.
The eruption was a dramatic and destructive event, with lava fountains from fissures beginning at South Pit, a crater immediately south of Moku'āweoweo (the summit caldera). The Wingate expedition reached the flows around 6:30 a.m. and witnessed the lava fountains, navigating around active flows and rapidly retreating to avoid getting trapped by advancing lava.
The summit activity ended by 5 p.m. that day, but earthquakes continued, at times strongly felt. This was attributed to magma migrating underground into the Southwest Rift Zone. On April 13, a yellow plume was seen on the Southwest Rift Zone, becoming more prominent and darker on April 14, indicating that lava was erupting from the rift zone.
The eruption continued until April 30, with another lava flow slowly advancing southeast in the direction of Wai'ōhinu in the District of Ka'ū. It stalled more than 5 miles (8 km) away, but the damage had already been done. The lava flow reached Government Road (what would later become Highway 11) on April 16 and crossed it in about two minutes, attracting hundreds of people to watch it.
The eruption had a profound impact on the local community, particularly the Ho'ōpūloa village, downhill from the active flow front. The village, home to Native Hawaiian and Chinese families, was destroyed by the lava flow, leaving an estimated 42 people homeless. Many of the displaced moved to Miloliʻi, and about 14 houses, a church, and the wharf were destroyed at Ho'ōpūloa village.
One of the most notable aspects of the eruption was the use of aerial photography to survey the active lava flows. The U.S. Army Air Corps, 11th Photo Section, based at Pearl Harbor, undertook surveys on April 17, 18, and 19, providing a new capability for situational awareness of where flows were headed.
The eruption also highlighted the importance of traffic and tourist management. The previous Mauna Loa eruption in 1919 had resulted in a panic, with at least 20 vehicles abandoned in a hurry. In 1926, the police managed the hundreds of people and their vehicles, directing traffic and establishing places for vehicles to turn around. This concerted effort ensured that people were not stranded and that all vehicles were parked away from the flow in case of rapid evacuation.
Today, safely maintaining and managing viewing areas remains a key consideration during eruptions in Hawaii. The USGS Hawaiian Volcano Observatory continues to closely monitor the volcanoes for signs of renewed activity, with Mauna Loa currently at a normal alert level and Kīlauea erupting episodically within the summit caldera since December 23, 2024.
In conclusion, the 1926 Mauna Loa eruption was a devastating event that had a profound impact on the local community. However, it also showcased the resilience of the people of Hawaii and the importance of effective management and monitoring during volcanic eruptions. A century later, the lessons learned from this eruption continue to be relevant, as the state remains vigilant in the face of ongoing volcanic activity.
