volcano to erupt, types of volcanic eruption

types of volcanic eruption

1. Composite volcanoes also known as stratovolcanoes, are large, cone-shaped volcanoes that are built up from layers of lava, ash, and other materials. They are known for their explosive eruptions

2. Cinder cone volcanoes are small, steep-sided volcanoes made of volcanic ash, cinders, and scoria. They are the simplest type of volcano and are formed when gas-rich magma erupts violently from a single vent. 

3. Shield volcanoes Shield volcanoes are broad, gently sloping volcanoes that are the largest volcanoes on Earth. They are formed by repeated eruptions of low-viscosity lava over long periods of time. 

4. What causes a volcano to erupt? Volcanoes erupt when molten rock called magma rises to the surface. Magma is formed when the Earth’s mantle melts. Melting may happen where tectonic plates are pulling apart or when one plate is pushed down under another. Magma is lighter than rocks, so it rises towards the Earth’s surface. If magma is thick, gas bubbles cannot easily escape, and pressure builds up as the magma rises. When the pressure is too much an explosive eruption can happen, which can be dangerous and destructive. Another way an eruption happens is when water underneath the surface interacts with hot magma and creates stream, which can build up enough pressure to cause an explosion. What determines the nature of eruption? Primary factors affect the volcanoes’ eruptive style. These factors can affect the magma’s viscosity in different way.  Magma’s temperature The viscosity of the magma decreases with temperature. The higher the temperature of magma is, the lower is its viscosity. As lava flows, it cools and begins to harden, its ability to flow decreases and eventually stops.  Chemical composition Magma with high silica content is more viscous than those with low silica content. The magma that contains less silica is relatively fluid and travels far before solidifying.

5.  Amount of dissolved gases it contains Gas (mainly water vapor) dissolved in magma tends to increase its stability to flow. Therefore, in near-surface environments, the loss of gases makes magma more viscous a dome or a columnar

6. Types of Volcanic Eruption Volcanoes erupt differently. They are generally classified as wet or dry depending on the magma’s water content. PHREATIC OR HYDROTHERMAL - is a stream-driven eruption, as the hot rocks come in contact with water. It is short lived characterized by ash columns but may be an onset for a larger eruption. Example is Taal volcano eruption in Batangas.

7. PHREATOMAGMATIC - is a violent eruption due to the contact between water and magma. As a result, a large column of very fine ash, high speed and side-way emission of phyroclatics called based surges are observed. Example is the eruption of Mt. Fukutoku- Okanoba in Bonin Islands Japan.

8. STROMBOLIAN a periodic weak to violent eruption characterized by fountain lava. Example is Mt. Irazu Eruption in Costa Rica.

9. VULCANIAN - characterized by tall eruption columns that reach up to 20 km high with pyroclastic flow and ash fall tephra. Example is Mt. Paricutin in Mexico.

10. PLINIAN excessively explosive type of eruption of gas and pyroclastics. Example is Mt. Pinatubo in Zambales.

11. Volcanic eruptions are one of Earth’s most dramatic and violent agents of change. Not only powerful explosive eruptions drastically alter land and water for tens of kilometers around a volcano, but tiny liquid droplets of sulfuric acid erupted into the stratosphere can change our planet’s climate temporarily. Eruptions often force people living near volcanoes to abandon their land and homes, sometimes forever. So, if the volcanologist knows the type of volcano based on the type of eruption and materials it emits, the communities at risk will be forewarned and there will be sufficient time to implement response and mitigation.

12. What is geothermal energy? The earth is believed to be extremely hot from within. This heat from the earth’s interior is a source of ener gy called GEOTHERMAL ENERGY. The heat of the earth warms up water which is trapped in rock formations beneath its surface.

13. How is geothermal energy generated? Geothermal energy is generated in two ways: Geothermal power plants Geothermal heat pumps They differ in the depth of heat source to produce energy.

14. Geothermal power plants. The heat from deep inside the earth is used to produce steam to generate to generate electricity.

15. Geothermal heat pumps Use the heat coming from close to the earth’s surface to heat the water or provide heat for buildings

16. In the Philippines, geothermal power plants are used to generate electricity . Tiwi(Albay) geothermal power plant.

17. Kidapawan(North Cotabato)

18. Calaca (Laguna) geothermal power plant

19. TONGONAN (LEYTE)

20. BAGO CITY(NEGROS OCCIDENTAL)

21. VALENCIA( NEGROS ORIENTAL)

22. BACON(SORSOGON)

23. Power plants are built in an area where it is particularly hot just below the surface such as near a group of geysers, Hot springs, or volcanic activity

24. Following steps are followed to generate electricity in a geothermal power plant . Wells are drilled deep into the earth to pump steam or hot water to the surface. When the water reaches to the surface, the drop in pressure causes the water to turn into steam. The steams spins the turbine, which is connected to a generator that produces electricity. Cooling tower cools the steam which it condenses back to water. The cooled water is pumped back into the earth to begin the process again.

25. Generating electricity from geothermal energy