There are about 1,350 active volcanoes on Earth. In 2022, people gathered to watch volcanic eruptions in Iceland, Hawaii, Tonga, and Indonesia. 4 of 74 confirmed eruptions this yearEarth has been volcanically active since it formed 4.6 billion years ago. At the solar system’s tumultuous origins, Earth was a giant ball of magma tens of millions of kilometers from the Sun, which slowly grew and cooled, forming a crust and trapping heat deep within the planet’s core.
The Earth’s molten core continues to cool slowly, and rising deep heat melts rocks and causes the plates of the Earth’s crust to move. That liquid rock is called magma when it’s at depth, and lava when it reaches the surface. Over millions of years, the magma and lava cooled to form the Earth’s crust, some of which still protrudes to the surface as lava flows, ash clouds, and volcanic gases. We pay close attention to volcanic eruptions because they pose a danger to human society and health. But the Earth as we know it would not exist without volcanic eruptions.
The chemistry and viscosity (fluidity) of magma/lava depends on the chemistry of the molten source rock, the temperature of the liquid, and the gas content. Less viscous lava flows like a river. Fagradalsfjall in Iceland’s Reykjanes Peninsula began erupting in 2021 after 815 years of volcanic quiescence, producing lava fountains and lava flows that fascinated people for several months before the eruption ceased. In August 2022, Fagradalsfjall began erupting again, Although no lava is currently being produced (as of December 2022), it is being closely monitored. Because there’s no doubt that Iceland will continue to experience eruptions in the future.
Iceland is an island made of lava. It sits on a plate tectonic divergence boundary and a volcanic hotspot, both of which bring magma to the surface and allow volcanic mountains to rise above the waves. In contrast, Hawaii is only on a hotspot (not near a plate tectonic boundary), but the Big Island is home to the largest active volcano on Earth, Mauna Loa, which began erupting on November 27, 2022, for the first time since becoming dormant in 1984.
Like the Iceland eruption Mauna Loa produces rivers of lava that erupt into the air and fall around the vent to form spatter cones.In addition to the danger of coming into contact with lava flows that exceed 900 degrees Fahrenheit, thin strands of lava cooled in the air can turn into golden glass strands known as “Pele’s hair”, which can be carried by the wind and pierce people’s skin, eyes and lungs. VOG (volcanic smog) is also closely monitored, as fine particles of sulfur dioxide and volcanic gases are very dangerous to breathe. For this reason, Mauna Loa is closed to tourists, but eruptions can be seen from afar.
The 1984 eruption of Mauna Loa was witnessed and studied by two of the most famous and influential volcanologists of all time, Maurice and Katia Kraft. They documented eruptions all over the world scientifically, and by photography and videography. They furthered the science of volcanic hazard assessment and eruption forecasting, and saved thousands of lives after they themselves were killed in the June 3, 1991 eruption of Mount Unzen in Japan by a highly viscous pyroclastic flow (superheated volcanic ash cloud). The documentary, “Fire of Love,” is currently on television. Disney+/National Geographic The film chronicles Krafft’s love story, research, and adventures, and is a compilation of photos and videos taken along the way. There is no other video of a volcanic eruption like this in the world. In my opinion, it is one of the most beautiful films ever made. However, I am biased, as I have loved volcanoes since I was 10 years old. The photos below are: Mauna Loa lava flow on March 25, 1984 Photographed by Katia Kraft.
Katia Kraft took the following photo, “Pele Dancing,” one of the most famous lava flow photographs in the world. Maurice and Katia Kraft Memorial Fund.
A pyroclastic eruption of thick, viscous water, similar to the incident that claimed the lives of the Krafts in 1991, occurred on December 4, 2022, at Mount Semeru on the Indonesian island of Java. Mount Semeru is one of the most active and dangerous volcanoes on Earth. Hundreds of people were evacuated before the pyroclastic eruption, and no fatalities have been reported, a much better outcome than the pyroclastic eruption almost a year ago. December 4, 2021, the day 13 people died on Mount SemeruThe most recent pyroclastic eruption, which occurred in December 2022, was caught on camera.
An even bigger eruption, in fact the largest of the 21st century, was recorded by cameras and satellites. On January 15, 2022, Hunga Tonga Hunga Ha’apai erupted, destroying an island just north of New Zealand. It created a 295-foot high tsunami, and the sound of the eruption was heard as far as Alaska. The eruption injected a huge amount of water into the atmosphere, increasing the water content of the stratosphere by 10%. Water is a greenhouse gas. The climate effects of this eruption are still being studied.
During eruptions, volcanic particles such as ash act as little umbrellas to block sunlight. This phenomenon is called “sun-darkening”. Pollutants emitted by human activities have a similar effect. Particulates are produced by burning cars, coal, and other pollutants. They block sunlight from reaching the Earth’s surface, and at the same time produce greenhouse gases, which absorb and retain the solar heat energy that does reach the Earth’s surface. However, greenhouse gases remain in the atmosphere for decades, so their heat retention lasts much longer than the sun-darkening effect of particulates, which only remain in the atmosphere for a few days or months.
The atmosphere is a delicate balance of incoming, absorbed, outgoing, and reflected energy. Gases, liquids, and solid particles have different thermal and reflective properties, and their combined effect determines the amount of energy retained in the atmosphere. The essence of this delicate balance is change, and so the atmosphere and climate are constantly changing. In the past, truly catastrophic volcanic eruptions have caused rapid climate change and plunged the world into volcanic winters (e.g., 1257 and 1815 AD). However, at present, humans are the greatest influence on the climate by releasing billions of tons of greenhouse gases into the atmosphere and heating the atmosphere and oceans. However, volcanic eruptions can occur at any time, exacerbating the effects of human activities on the atmosphere. Earth is full of surprises, and has remained so throughout its 4.6 billion years of continuous change.
