Volcanic Disasters and How They Happen

By Kyzia Maramara

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Bicol’s Mayon Volcano has been creating quite a ruckus the past week and whether you admit it or not, it’s got everybody curious to know more about volcanoes and how they work. Volcanoes are beautiful disasters we’re prevailed to witness every now and then. How much do we really know about them?

1. Volcano origins and how they’re made

 

Mayon Volcano under the starry night
(cinemagraph)

Posted by Jerry Jethro Calag Photography on Saturday, January 20, 2018

If you’re familiar with mythology, you might know that the word ‘volcano’ is derived from the highly volcanic Latin island Vulcano which in turn is named after the Roman god Vulcan (Greek: Hephaestus) believed to have power over the fires of volcanoes.

Volcanoes are fissures in the Earth where molten rock (magma), hot gases, and rocks are ejected, it’s also the landform produced as part of the eruption. Kind of like a breakout of pimples on Earth surface. Active volcanos are deadly and are a threat to humans residing near it and eruptions can have an effect on the ecosystem that could last for years.

 

2. What triggers the eruptions

Mt. Mayon spews ash from minor eruption (2018)

Long story short, the reason for an eruption could be because magma within the Earth is pushed up, or when tectonic plates move.

Underneath the Earth crust is the mantle where temperatures are high and pressures increase. Magma, molten rock, gets pushed to the surface and erupts into lava, ash, and rock.

Most volcanoes are located on the Pacific Ring of Fire, a huge area in the Pacific Ocean where most volcanic activities and Earthquakes occur. These are results of plate tectonics moving apart, sliding, and colliding with each other causing magma to rise to the surface.

 

3. Sign of the times

Mayon’s eruption (2018)

Depending on how it’s closely monitored, there could be plenty of warnings before a volcano erupts. According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS) it could be increase in volcanic tremors, change of steam from white to gray due to ash, crater glow due to presence of magma in the crater, increase of temperature in hot springs, wells, and crater lakes, and drying up of springs among others.

They use equipment that measures and detects Earthquake activity (seismometer, a device used to measure vibrations of the Earth), volcanic gases, water temperature, and how much lava is moving underground.

When volcanologists have enough evidence that a volcano might be erupting soon, they alert the government to carry out emergency measures.

 

4. Volcanic eruption mini dictionary

Pyroclastic Flow

It might be a challenge to understand the news we read about volcanic eruptions, sometimes they aren’t explained clearly. Here are some of the words mentioned in everyday news, simplified:

Phreatic explosion/eruption: Steam eruption without lava caused when magma heats ground or surface water. The high temperatures cause the water to flash to steam generating an explosion.

Pyroclastic flow: Pyro in Greek means ‘fire’ and clastic means ‘broken.’ Pyroclastic flows are dense and destructive mixtures of hot ash, volcanic fragments, and gases that flow from the volcano at speeds reaching 100 miles per hour.

Tephra: Rock fragments and materials of all shapes and sizes that gets ejected into the air during a volcanic eruption.

5. Worst volcanic eruptions in history

Mt. Vesuvius eruption in 79AD oil on canvas painting by Pierre-Jacques Volaire

The most famous worst volcanic eruption would have to be Mt. Vesuvius in 79 AD which buried the Roman city of Pompeii and Herculaneum under volcanic ash killing thousands. The city was forgotten until an excavation was made in 1748 and it was discovered that the ash actually helped preserve the whole city. Since then scientists have been continuously uncovering artifacts and finding out these people’s way of living.

And yet deadlier than Mt. Vesuvius is Mt. Tambora’s eruption in 1816. Mt. Tambora is located on the island of Sambawa, Indonesia and when it erupted, the death toll rose up to 90,000.

 

6. Active volcanoes in the Philippines

Via Wired

Mt. Pinatubo eruption (1991)

On June 15, 1991, the second largest explosion of the century happened. Mt. Pinatubo erupted for hours expelling tons of ash and clouds of gasses. The volcanic ash spewed 21 miles into the air and scattered to form a cloud of 250 miles, to make things worse, there was a typhoon the same time as the eruption. Fortunately, only a few hundred people died, some even dying because of collapsed roofs due to thick ash and rain.

The explosion of Mt. Pinatubo and the cloud of ash lowered the temperatures globally throughout the next few years.

 

7. The benefits of volcanoes

Mayon Volcano

Volcanoes will always be known for their powers of destruction but did you know that on the other side of the lahar, lava, pyroclastic flows, and death tolls there are actual natural benefits we can reap from eruptions?

Volcanoes first and foremost, can help create new land. The Hawaiian Islands are an effect of the eruption of underwater hotspots or volcanoes. Volcanic rocks contain minerals also beneficial for soil enrichment, this is why lands near volcanos always have fertile soil. Dried lava could be used for building roads and buildings. Volcanoes are also sources of geothermal energy, natural energy that could generate electricity.

Volcanoes are a part of nature and it serves its purpose.

 

8. What’s happening to Mayon Volcano now?

Mayon Volcano is the perfect cone-shaped volcano that’s known to be the most active volcano in the country. Its worst eruption took place in 1814 destroying Casagawa church which was about 10 km from the volcano. Mayon has been estimated to have erupted for 50 times since the first recorded explosion in 1616.

Since its last major explosion in 2009 and renewed activity in 2014, Mayon has apparently awakened from its slumber once again. Since Monday (January 15) the volcano has been spewing lava, ash, and gases, and PHIVOLCS have reports about pyroclastic flows on the side of the mountain.

The alert level is now raised to Alert Level 4 which means hazardous eruption is imminent. Thousands of residents are evacuated as the government aims for zero casualties if Mayon does have a full eruption in the next few days.

Classes in all levels private and public are now suspended in the whole province of Albay. Everyone is advised to wear…

Posted by Gov. Al Francis C. Bichara on Sunday, January 21, 2018

 

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