Good day students! It's been a long time. Welcome back to Maesrang Techie YouTube channel. First of all, I would like to congratulate everyone because we are now halfway completing grade 9 science. We are now in quarter 3 which is above earth science.
Good job class for making it here. Our first lesson for this quarter is about the different types of volcano. This is our learning objective. Describe the different types of volcanoes and volcanic eruption. So, listen carefully and keep on watching!
Before we start, let us have some unlocking of difficulties. Let us define some terms that you will encounter. Let us define what volcano is. Volcanoes are natural opening in the Earth's surface where molten rocks, smoke, gases, and ashes are ejected. Have you seen Mayon Volcano located in Albay, Bicol, Philippines?
Did you know that Mayon Volcano is one of the world's most active volcano? And it is very popular because of its perfect cone. Volcano has three basic parts, namely the base, the slope, and the summit where the crater or opening is located. Speaking of crater, crater is a funnel-shaped depression at the top of a volcano formed as a result of explosive eruption. It is the mouth or the opening of the volcano.
Do you know this volcano? This is Taal Volcano located in Batangas, Mexico. Philippines. This volcano has many craters, not just one, two, or three, but 47 craters. Amazing, right?
It is a volcanic crater that is formed when a part of the wall of the crater collapses following an explosive eruption. A caldera collapse is usually triggered by the emptying of the magma chamber beneath the crater. the volcano as the result of a large volcanic eruption. When we say magma, it is a hot fluid or semi-fluid material below or within Earth's crust that is usually made of magma. from molten rocks.
When the magma ejected out of a volcano it is now called lava. When the magma is ejected out of a volcano it is now called lava. Lava is an Italian word which means to slide which is what molten rocks does once it reaches the surface. Now, let us proceed to the different types of volcano. Volcanoes can be classified according to its shape and according to its eruption.
Let us have first the types of volcano according to its shape. shape the first type is shield volcano this is formed by the accumulation of lava oozes out from the volcano since non-viscous lava can flow free Really, a broad, slightly doomed structure that resembles a warrior's shield is formed. That is why it is called Shield Volcano because it looks like a warrior's shield. Example is Mauna Loa in Hawaii.
The second type is what we call Cinder Cone Volcano. This is built from ejective lava fragments. They have steep slope, wide slope, and steep slope.
crater and is most abundant of the three major volcanoes it is also known as scoria cone example is Mount Percutin in Mexico as you can see it has a steep slope and has a wide crater that are characteristics of a cinder cone volcano lastly we have composite volcano it is also known as stratovolcano this is large nearly perfect slope structure formed from the alternate solidification of both lava and pyroclastic deposits. According to volcanologists or the people who study about volcanoes, some of the Earth's grandest mountains are composite or stratovolcanoes. One good example is our very own Mayon volcano.
And those are the three types of volcano according to its shape. Again, we have Shield volcano that is broad and resembles a warrior's shield. Cinder cone volcano, also known as scoria cone and has wide craters.
Composite volcano or also known as scoria cone. known as stratovolcano with nearly perfect slope structure. But why do volcanoes have different types?
It is because the process of magma formation is different at each type of plate boundary. Therefore, the composition of magma differs in each tectonic setting. Now, let us have a short activity.
Let us identify the following volcanoes as Shield Volcano, Cinder Cone Volcano, and Composite Volcano. Let us start. This is Mount St. Helens in southwestern part of Washington State. And this is an example of Wright Class Cinder Cone Volcano. Let us start.
Let's have this beautiful Mount Fuji in Japan. What do you think is this type of volcano? This is composite volcano.
Very good class. Next, we have Mauna Kea in Hawaii. This is an example of shield volcano. Good job, class!
Now, let us go to the different types of volcanic eruption or the types of volcano according to its eruption. The first one is phreatic. It is a stream-driven eruption as the hot rocks come in contact with water.
It is also known as hydro- Phraetic eruption is the type of eruption that happens to Taal Volcano last January 12, 2020. Next we have phraetomagmatic. It is a violent eruption due to the contact between water and magma. Unlike phraetic that happens because hot rocks come in contact with water, phraetomagmatic eruption happens if there is an interaction between water and magma.
and magma, resulting to a violent fine ash eruption. The third is Strombolian. It is a period weak to violent eruption characterized by fountain lava. As shown in your screen right now, it is a fountain lava. The fourth one is what we call Volcanion.
It is characterized by tall eruption that reach up to 20 km high with pyroclastic flow and ash fall tephra. Again, it is characterized as tall eruption. Lastly, we have Plinian. It is excessively explosive type of eruption of gas and pyroclastics.
It is intensely violent kind of eruption that happens to Mount Pinatubo year 1991. Again, the five types of volcanic eruption are Phriatric or the stream-driven eruption that happens between the contact of hot rocks and water. Phreatomagmatic that happens between the interaction of magma and water resulting to a violet fine ash eruption, Strombolian eruption or characterized as fountain lava, Vulcanian or characterized as tall eruption, and Plinian as the most excessively explosive eruption. Moreover, we can also classify volcanoes according to its record of eruption. Active volcano A volcano is active if it has a record of eruption. On the other side, a volcano is inactive if it shows no activity and no record of eruption.
Just like Mount Canlaon in Negros Occidental, Philippines. We are going to discuss more about this on our next video. To end our lesson, we can thank volcanoes for life on Earth.
To put simply, volcanoes can be used to create a new world. keep the earth warm and wet which are two critical elements for sustaining life thank you so much for watching i hope you learned something new again we will continue this lesson on my next video so please do subscribe like share and click the bell button bye class