Hawaii: Manua Loa eruption no longer a threat to infrastructure and Ironman

Mauna Loa’s eruption on Ironman’s Big Island may be coming to an end. The world’s largest volcano had been spitting fire for around two weeks – for the first time in 38 years.

J. Bard (USGS) The last active slot on the northeast flank of Mauna Loa on December 10, 2022.

Although Mauna Loa had erupted every five years on the historical average of the decades, the mountain had been silent for the last time since 1984. Since September, earthquakes and deformations have announced a new eruption, on November 27, 2022 at around 11:30 p.m. the giant erupted in the summit crater called Mokuaweoweo out. By the next morning, the eruption had shifted to the upper northeastern rift zone.

The fountains of liquid rock sometimes shot up more than 100 meters. The most active lava front was moving at speeds of 100 meters per hour toward the Daniel K. Inouye Highway – the former “Saddle Road” connecting volcanoes Mauna Kea and Maunla Loa connecting the island’s capital Hilo to the east with Kona, popular with tourists and triathletes -coast to the west joins.

Destroying the highway would have posed extreme challenges to the infrastructure of the Big Island. That and the ash and gas emissions associated with a volcanic eruption were discussed as possible scenarios that might have endangered the staging of the Ironman and Ironman 70.3 Hawaii, even in a reduced form.

Short lava flows no longer pose a threat

On the 13th day of the eruption, geologists from the United States Geological Survey (USGS) gave the all-clear: “The lava eruption from fissure 3 in the northeastern rift zone of Mauna Loa is continuing, albeit with greatly reduced lava flow and volcanic gas emissions. Most of the lava is in a small pool at the vent. The short lava flows that were active yesterday regarding 1.5 miles from the vent have stopped, the lava flow front has stopped three kilometers off the Daniel K. Inouye Highway and is no longer a hazard.” of the eruptive behavior in the past, that the high eruption rates will not occur once more: “The current behavior indicates that the eruption might end soon. There is a small chance that the eruption will continue at very low eruption rates.”

For these reasons, the Hawaii Volcano Observatory (HVO) is lowering the volcano alert level from the highest of the four levels, Warning, to the third highest, “Watch,” reflecting the manageable dangers of current activity. The aviation color code remains “orange” to reflect the uncertainty of ongoing eruptive activity and the possibility of volcanic ash emission.

Hardly any damage to property and only minor personal injury

The recent eruption of Mauna Loa caused little damage as the eruption was limited to the northeastern part of the mountain. The flank of the 4,170 meter high volcano falls less steeply than in the southwest, where lava flows would have reached the sea and possibly also populated areas within a few hours. The destruction of the infrastructure was now limited to a small access road to an observatory on the mountain used for climate research and its power supply. Nevertheless, people were also injured – in minor rear-end collisions involving onlookers on and along the Daniel K. Inouye Highway.