Giants with Explosive Powers

Mauna Loa (“Long Mountain”) rests inconspicuously on the horizon behind the volcanic cone of Mauna Kea (“White Mountain”), which appears more violent. Measured from the seafloor, Mauna Kea is the highest mountain on Earth, but nevertheless inactive as a volcano. Mauna Loa in turn, hardly smaller, rises four kilometers above the Pacific Ocean and, with an area of over five square kilometers, is one of the largest active volcanoes on Earth. Since 1984, Hawaii has been quiet, except for minor Earth tremors, but the New York School of Marine and Atmospheric Sciences is alarmed: satellite data and GPS stations prove that the peak of the sleeping giant rose by about six centimeters a year between 2014 and 2020. The reason is an underground magma flow. However, an eruption is not expected soon, but the Hawaiian Volcano Observatory wants to keep a close eye on the mighty volcano.

For almost 800 years, the volcano Fagradalsfjall, located in Iceland’s southwest, kept its peace, before 50,000 smaller earthquakes within the span of three weeks announced its eruption. In the evening of March 19, 2021, the spectacle came to a grand finale. A spectacle indeed – the eruption on the Reykjanes peninsula turned out to be moderate and did not pose a threat to surrounding cities; the closest city, Nátthagakriki, was located almost 10 kilometers away. The natural wonder attracted thousands of onlookers – the images and movies of the glowing viscous mass, captured by the people of Iceland, allowed audiences from around the world to take part, and international research teams took advantage of the good geological location for their studies. One thing is evident: due to the massive seismic energy that was released, additional, stronger eruptions are to be expected. The timing, however, is a secret held by Fagradalsfjall alone.

“Very high” – such is the official hazard potential of Mount St. Helens in Washington State, USA. This active stratovolcano made history on May 18, 1980, when a magnitude 5+ earthquake triggered a series of severe subsequent events: at 8:32 am local time, a massive landslide of rubble tore the top 400 meters of the volcano all the way to the bottom. Shortly thereafter followed the actual Plinian eruption – an explosion with a pillar of smoke 24 kilometers high. 540 million tons of ash were carried eastward across the United States by the wind, darkening the skies. 57 people died – making this volcanic eruption the deadliest in the history of the US. What was left behind was a crater; its ever-growing Godzilla Hole, a glacier cave, continues to attract researchers who climb down inside to study the fascinating life forms therein.

Powerful tsunamis, destructive earthquakes, red-hot clouds of smoke and streams of lava originating from volcanoes – the Pacific Ring of Fire constitutes the geologically most active region on Earth. At least 450 active or temporarily dormant volcanoes make up the 40,000 kilometer-long belt which circumscribes the Pacific Ocean. The subduction process, during which one tectonic plate pushes underneath another, causes the creation of enormous pressure in some regions. Eventually, this pressure will be released in the form of earthquakes and volcanic eruptions. One country that is particularly affected is Indonesia: its volcano Bromo, on the island of Java, most recently spewed white-gray clouds of ash in May 2021. The 2,329 meter-high stratovolcano, named after the Hindu god Brahma, is located, along with three other volcanoes, in the Tengger Caldera – an 820,000 year-old collapsed crater. Together, they form an unusual landscape – which might as well be on another planet.