Mauna Loa, the largest volcano in the world and one of five located in Hawaii, has erupted this monday. It is a sleeping ‘monster’ that emerged from the bottom of the ocean some 400,000 years ago and has a height of more than 10,000 meters, adding up its emerged parts and below sea level, above the highest mountain in the world, the Everest.
After remaining inactive for almost forty years, since April 1984, it puts the whole island on alert again. At the moment, the lava flows are contained within the summit area and do not threaten the communities located on the hillside.
Vicente Soler Javaloyesan expert volcanologist and scientific researcher at the CSIC, explains to 20 minutes the main characteristics of this volcano.
The largest in area and volume
Mauna Loa is one of the largest volcanoes on Earth. It covers an area of about 5,271 square kilometers and its width is approximately 120 kilometers. As for its volume, it occupies about 80,000 cubic kilometers. Hence its name, which translated from the Hawaiian language means “long mountain”.
Mauna Loa is in first position in terms of area and volume, but its neighbor, Mauna Kea, surpasses it in height: the first measures about 4,169 meters above sea levelwhile the second reaches 4,207 meters.
To those almost 4,170 meters high, we must add another 6,000 meters that are below sea level. “These stratovolcanoes are even bigger than Everest,” explains Soler. Everest reaches 8,849 meters above sea level. The Mauna Loa exceeds 10,000 real meters of height. “It’s a huge mountain. Very flattened, but gigantic,” says the expert.
It emerged from the ocean floor about 400,000 years ago.
The Hawaiian Islands emerged from the sea about 30 billion years ago, forged by the power of volcanoes. “Hawaii is currently in the hottest spot on the planet”, acknowledges the scientist. The Kohala, Mauna Kea, Mauna Loa, Hualalai, and Kilauea are heThe five volcanoes that make up the Big Island of Hawaii.
The Mauna Loa is the second youngest. It emerged from the ocean floor about 400,000 years ago, while Mauna Kea is about a million years old. Mauna Loa’s growth rate has slowed considerably from about 100,000 years ago.
It’s known that 98% of the volcano’s surface is made up of lava emitted in the eruptions of the last 10,000 years. This also shows that he is one of the youngest.
a peculiar structure
Mauna Loa, like its island neighbors, is a shield volcano. This means that it’s a leaning mountain: It has the shape of a long dome that extends to the bottom of the ocean. “It is difficult to appreciate the volcano that is widespread,” says Soler.
Its slopes have a maximum slope of 12 degrees at its steepest point. This structure is the result of large number of flowing lava rivers that emanated from ancient eruptions. “The entire island of Hawaii is characterized by fairly fluid lava emissions at high temperatures,” says the volcanologist. It reaches approximately 1,300 degrees.
Four craters and a caldera of more than 180 meters
At the top of Mauna Loa is a caldera called Mokuʻāweoweo, formed by overlapping pit craters and arranged from northwest to southwest. This caldera gets its name from the Hawaiian ʻāweoweo fish (Priacanthus meeki) due to the similarity of their eruptive fires with the coloration of fish.
The Mauna Loa has four subsidence craters -means that they are formed by the subsidence or collapse of the surface located above a vacuum chamber. Their names are: Lua Hohonu, Lua Hou, Lua Poholo, and South Pit. The first two are to the southwest of the caldera. “Actually, they are depressions,” says Soler. These form a rim that confines the lava. “Inside the depressions is where the multiple craters are,” he adds.
one of the most active
Despite taking so many years without any type of movement, Mauna Loa is considered one of the most active volcanoes on the planet. “Until 1950, it erupted every five years.. After that decade, the volcano has had less activity,” explains Soler.
There is no record of eruptions that occurred millions of years ago, but numerous scientific studies speak of a fairly long history. It is believed that the first eruption took place a million years ago. Since then, subsequent eruptions have caused it to expand its surface, volume, and height.
The Global Volcanism Program of the Smithsonian Institution has counted, at least, 109 confirmed eruptions. The first of which there is a record dates from the year 1843 and, since then, there have been expulsions of material from the interior some 35 more times. Despite its great activity, experts do not consider that it has too much intensity in its eruptions.
Almost 40 years of inactivity
The volcano It had been inactive since 1984. “This is the longest period that the volcano has had without eruptions,” says the volcanologist. In this latest eruption, it did not cause fatalities, but it did destroy several villages.
Two months ago an increase in seismicity and ground deformation began to be noticed. For now, the eruption is confined. “It seems that half of the eruptions from this volcano ended up migrating abroad,” warns Vicente Soler. We will have to wait to see how it evolves.