Volcano Eruption : How & Why

OK. Let's talk about natural hazard

    So, before jumping in, let's understand the technical terms used for this kind of event

    What is Natural Hazard?

            In simple way, Natural Hazard is a threat of a naturally-occuring event that has a possible negative effect on humans. It includes earthquake, tsunami, typhoon, wildfire, etc. Those kind of events can have an impact in our daily life. But then, what is the difference between hazard and disaster?

            So, we know natural hazard is THE THREAT of a natural event to the human race. Meanwhile the meaning for Natural Disaster is an incident that occurred AFTER a natural hazard happened and significantly harm and DAMAGE the community. Then, from the meaning above, we can differentiate which event is a threat or an incident that happens to affect our daily lives. 

            And, Let's go back to the pictures before!

    What is a Volcanic Eruption?

            Volcanic eruption is term used when molten material from inside the earth is extruded from inside of the earth. Volcanic eruption can make a significant difference in human lives and indirectly affects how we adapt in this world. 

            In the past, people usually lives around a water springs or rivers, but over time, some lived in the top of the land. They were usually have a background of farming and agriculture, so they lived where the soil, moisture and humidity was perfect for growing specific types of plants. In the course of human history, the demand for those specific types of plants are increasing, so the farmers uphill take their yields to downhill and sell it to the market. Finally, a free market grows and there is a distribution from the mountain region to town. But still, a natural hazard can't be denied. Most of the time, the farmers were located on a volcanic mountains and the mountain has the potential of eruption. Thus, the human life was and still is interconnected with the natural hazard itself.

            So, it can't be denied that volcanic eruptions is one of the natural hazards and we, as humans, have a long history related to it. With the development of technology, we can finally given what happens inside the earth that caused the volcanic eruption.

            How does it happens?

            Volcanic eruptions occur when molten material from the Earth's interior is extruded to the surface through volcanic mountains. Those molten material is a mix of dissolved gases and hardened mineral which we called Magma.

            Magma is formed right below the earth's crust when there is a rupture in earth's crust which enabling seawater to enter the second layer of Earth. Then, the seawater will lower the melting point of rocks in the second layer. The resulting phase is the magma in its liquid form

            Meanwhile, if the temperature and pressure is higher than usual, material like sulfur and water won't dissolve into magma. Instead, they will form high-pressure bubbles that will cause a buoyant force. In the end, if the buoyant force is high enough, then the pressure in the magma chamber will rise up and push the magma out.

            When magma from the second layer were pushed, it will flow in a space between rocks and eventually reach up into a chamber called Magma Chamber.

            

            When the bubble before has reached the magma chamber, it will likely cause the magma to flow to the main vent and blow up to the surface of the Earth.

            Another factor that affect the tendency to erupt are lithostatic pressure and magmastatic pressure. Lithostatic pressure is the pressure caused by the weight of the earth's crust relative to the second layer. While magmastatic pressure is the pressure caused by the temperature of the magma inside the second layer

            The lithostatic pressure and the magmastatic pressure cause an equilibrium in the border of the crust and second layer. Those two will keep balancing each other, but usually there is a condition and time where the magmastatic will be higher than the lithostatic pressure. Such an example is a shift in the tectonic plate can affect the lithostatic pressure and it will make an eruption more likely to occur.

            Fun Fact : 

                

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                Earthquakes and volcanoes commonly occur in the boundaries of tectonic plates.

                The Pacific Ring of Fire, for example, is a horseshoe-shaped belt in the Pacific Ocean where active volcanoes and frequent earthquakes occur. It stretches from the island of New Zealand to Indonesia, then to Japan and curling over to America and South America. 

                What Are The Effect of Volcanic Eruptions?

            Volcanic eruptions can impact climate change through emitting volcanic gases like sulfur dioxide, which causes global cooling, and volcanic carbon dioxide, which has the potential to promote global warming.

            Volcanic eruptions also can pose multiple health threats depending on the proximity of the volcano to  the community and whether there was any warning.

            Volcanic eruptions can cause :

• Suffocation
• Infectious diseases, such as conjunctivitis
• Acute and chronic respiratory diseases from falling ash and breathing gases and fumes
• Burns and traumatic injuries, such as lacerations from falling rock
• Eye and skin irritations from acid rain.
• Ash and chemicals from the eruption can also generate risk of food and water contamination, and compromise basic services, like water, transportation, communications and health services. Likewise, the accumulation of ash on roofs can cause damage or collapse of buildings, both immediately and after the event.

                Types of Volcanoes

            There are 3 types of volcanoes that are known to many people :

1. Cinder Cones Volcanoes
2. Composite Volcanoes or Stratovolcanoes
3. Shield Volcanoes

           Shield Volcanoes

            Although shield volcanoes are the largest volcanoes on Earth, they do not form soaring mountains with conical peaks like composite volcanoes. Shield volcanoes have very gentle slopes of only a few percent that become even more gentle near the summit.

Stratovolcanoes / Composite Volcanoes

            Composite volcanoes can be the most picturesque of all volcanoes. A classic composite volcano is conical with a concave shape that is steeper near the top. They may have multiple vents, but most composite cones have a main vent at the summit. Active composite volcanoes usually have a shallow magma chamber at depths of 3-6 miles (5-10 km).

Cinder Cones Volcanoes

            Cinder cones are the most common type of volcano in the world. Cinder cones are more technically known as scoria cones. Most cinder cones are a few hundred feet tall (100 to 150 m), and rarely are larger than 600 to 900 feet (200 to 300 m) in height. Each cinder cone usually is its own edifice built up around a central vent.

        Conclusion

                Volcanic eruption is a threat of a naturally-occuring event that has a possible negative effect on humans. So, hopefully humans can create a new techonology that can help human to adapt to volcanic eruption. Although volcanic eruption has a negative effect on humans. But on the opposite, volcanic eruption can help the nature because it could make the land fertile, thus help the animal growth in the future.

                

                I think this conclude our material. Hope you  enjoy and learn something from this. Tschüß