The Hawaiian Islands are unique because they are the only U.S. territory formed entirely of volcanic rock. Its mainland outcrops began to form more than 70 million years ago, thanks to the emergence of the volcanoes that make up the islands. Hawaii currently has three major active volcanoes that constantly issue alerts, but in recent days the Mauna Loa volcano has joined them as it has shown activity for the first time since 1984.
It was thought that the lava would remain in the caldera
The Hawaii Volcano Observatory (HVO) issued an alert during the night of November 27, when the famous Mauna Loa volcano located in Volcanoes Park erupted after remaining calm for 38 years.
The U.S. Geological Survey (USGS) quickly shared images of a long fissure from which lava fountains were gushing out and spreading along the floor of the volcano’s caldera. Initially, the USGS and HVO said that the lava only remained in the caldera and that there was no danger to the surroundings of Mauna Loa.
The HVO indicated that the eruption had begun at Moku’aweoweo, as the volcano’s caldera inside it has been named. “At this time, lava flows are contained within the summit area and are not threatening downslope communities,” officials said. At this time the greatest threat was ash and volcanic gas carried by winds.
[Moku’aweoweo Caldera. Photo: Donald W. Peterson, USGS.]
“If the eruption remains at Moku’aweoweo, lava flows will most likely be confined within the caldera walls. However, if the eruptive vents migrate away from its walls, lava flows may move rapidly downhill,” added the Hawaii Volcano Observatory.
But later, residents on the Kona side were able to record images that appeared to show lava flowing down the mountain. Precautionary measures implemented by Volcanoes National Park included the closure of cabins, as well as high-altitude areas surrounding Mauna Loa due to the significant increase in seismicity.
The largest volcano in the world
Mauna Loa is one of the five volcanoes that make up the island of Hawaii and is the largest volcano in the world in terms of volume. It is so large that it covers more than half the surface of Hawaii, with an estimated volume of 75,000 cubic kilometers.
It is believed to have emerged from the sea some 400,000 years ago, since when it has been active. However, it had not shown activity in recent years, in fact, it had been dormant since 1984 when it erupted for almost a month from March 24 to April 15 of that year.
Its summit houses three overlapping subsidence craters that together form the Mokuʻaweoweo caldera, whose total size is 6.2 by 2.5 kilometers. It is one of the most imposing volcanoes in the world because although it is not the tallest, it is the one that occupies the largest volume of all the giants on the planet.
Story originally published in Spanish in Ecoosfera