Hawaii Volcano Erupts After 38 Years Dormant

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To a volcano, erupting is like emptying a truck. But to us, an eruption could cause unwanted destruction. And one volcano looks like it has a lot of unloading to do after laying dormant for 38 years.

This volcano is in the south-centre part of Hawaii island in the Pacific. Known as Mauna Loa, or “long mountain” in Hawaiian, it truly is a giant, considered the largest active volcano on Earth. It rises roughly 4170 meters above sea level, with a dome 120 km wide. The previous eruption of this volcano was in 1984. It again started erupting on November 27th of this year and continues in some areas.

However, it’s good news that the remaining fissures of Mauna Loa that are still spewing, fissures 3 and 4, are slowing to a sluggish speed, though it is still flowing downslope. So what causes a volcano to form, erupt, go dormant, or extinct, and what damages could one cause?

All volcanoes, big or small, start with magma hidden beneath the crust or the outermost layer of rock. The Earth, like a cake, consists of many different layers, and the crust is only the most outer layer of frosting. On the inside, there is the mantle, then the outer core, and finally, the inner core of our Earth. Magma, consisting of rocks, metal, and other things, is found in the mantle. It circulates under our feet, waiting for a chance to burst through the crust.

Thankfully, some factors keep the magma at bay, though those same factors could also cause an eruption. The first factor is lithostatic pressure, the crust’s weight pushing on the magma below. However, magma also pushes back with the second factor, magmastatic pressure, fueled by the gas trapped within the magma, with the same effect as a boiling pot of water. Magma is the boiling water, with the water vapour causing magmastatic pressure. The pot’s lid and sides contain the pressure.

But enough stress caused by the constant hammering of these two factors weakens the third factor, rock strength, or the metal sides and lid of our boiling water pot. It is rare for your pot to burst since the water vapour usually isn’t enough to break metal. However, magma sometimes can. When the magmastatic pressure exceeds the rock strength and the lithostatic pressure, it bursts through the crust, and magma (now known as lava after reaching the surface) rushes out, which is what we see at ground level. Fortunately, it takes a long time for pressure to build, like in the case of our pot, which gives scientists time to detect possible temperature and pressure changes, potentially evacuating nearby residents to save them before the disaster.

But not all volcano eruptions are caused by such a build-up. More commonly, a shift in plate tectonics causes it to happen more quickly. The Earth’s crust isn’t one shell. It’s more like pieces in a puzzle. The problem is that these pieces don’t fit very precisely, which often causes two kinds of phenomena.

The first phenomenon is the collision of these two plates, also known as convergent plate boundaries, a pushing match to see who gets to be on top. The winning plate slides over the lower plate to form mountain ranges (like the Himalayas) and volcanoes. The volcanoes formed in this process are known as composite volcanoes or stratovolcanoes and have steep sides. The losing plate, however, is sent under to a fiery hell, the mantle. The crust slowly gets melted by the hot temperatures and significantly builds pressure bubbles of carbon dioxide and water vapour, which ultimately causes an eruption. It’s an act of powerful revenge from the loser before it’s forever melted into the mantle. The crust opening could cause another volcanic discharge because the magma gets directed to that spot by the thicker crust. Due to this convergent process came the term Pacific Ring of Fire. It indicates the volcanoes around the edge of the Pacific plate, where such plate tectonic activity happens frequently.

The second phenomenon, divergent plate boundaries, means two tectonic plates moving apart. That creates an opening in the Earth where the bubbling magma could burst through. Divergent plate boundaries also form a type of volcano, a rarer kind known as a shield volcano because its shape resembles a shield. These volcanoes don’t have as steep sides and could have giant bases. Shield volcanoes commonly don’t have too violent eruptions. Their eruptions are like an overflowing sink, with the water slowly seeping down the sides and solidifying. The lava-turned-rock is known as igneous rock. Mauna Loa is a shield volcano, despite its magnificent height. Height is more of a time problem to shield volcanoes since not much igneous rock gets built up at the top. Other volcanic types include cinder cone volcanoes, like the volcano Parícutin located in Mexico, formed through the flying lava landing back on the vent; dome volcanoes, a smaller one formed after the collapse of a composite one; etc.

So what could cause a volcano to become dormant or even extinct? Well, since all volcanoes start with magma, their end should also involve an absence of it. The extinction of volcanoes is usually because, after a giant eruption, whereby it fully empties its magma chamber and is unable to get new magma supply. Without magma supporting the volcano underneath, it could collapse under its weight, forming a volcanic crater known as a caldera. On the other hand, the emptying of magma in their chamber causes dormant volcanoes. It takes some time to refill, so until then, a volcano stays dormant.

There are many damages that one volcano eruption could cause. In a small-scale volcanic eruption, lava would be the force of destruction and could engulf the surrounding infrastructure and houses, potentially causing casualties. However, a much worse thing gets produced through a supervolcano eruption. Large amounts of ash and smoke are shot into the stratosphere and carried by winds to blanket nearby places with a giant ash cloud, blocking sunlight. It could even spread halfway around the Earth, causing much disruption in crops and livestock growth, famine, and acid rain falling in some places. Scientists believe that the so-called “Little Ice Age,” which lasted from around CE 1300 to 1850 and showed a cooling of global temperatures, was caused by explosive volcanic eruptions and the cooling effects that came with it.

So what are things that scientists could do to try and prevent such a disastrous event? As of current technology, detecting a spike in temperatures beneath the crust could signal a possible eruption. Also, detecting earthquakes that are possibly resulted from magma surges is promising. The most important thing to avoid a disaster is to listen to the experts. If you live nearby or plan on visiting a volcano, check safety regulations and reports of the area to ensure you’re in a safe environment.

I hope that in this article, you learned more about volcanoes and always remember to stay safe around them. That’s the end of this production from the New News Newsminute. Thank you for reading, and tune in next time for more updates.