1. VOLCANOES

2. WHAT IS A VOCANO? A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.

3. HOW ARE VOLCANOES FORMED? Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

4. WHAT ARE THE DIFFERENT STAGES OF VOLCANOES? Scientists have categorized volcanoes into three main categories : 1.ACTIVE VOLCANO is one which has recently erupted and there is a possibility that it may erupt soon. 2.DORMANT VOLCANO is one which has not erupted in a long time but there is a possibility it can erupt in the future. 3.EXITINCT VOLCANO is one which has erupted thousands of years ago and there’s no possibility of eruption.

5. WHY DO VOLCANOES ERUPT? The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. The friction causes earthquakes and volcanic eruptions near the edges of the plates. The theory that explains this process is called plate tectonics.

6. WHAT ARE PLATE TECTONICS? The theory of plate tectonics is a interesting story of continents drifting from place to place breaking apart, colliding and grinding against each other. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes.

7. WHAT ARE THE DIFFERENT TYPES OF VOLCANOES? Volcanoes are grouped into four types: 1.CINDER CONES 2.COMPOSITE VOLCANOES 3.SHIELD VOLCANOES 4.LAVA VOLCANOES

8. CINDER CONES Cinder cones are circular or oval cones made up of small fragments of lava from a single vent that have been blown into the air, cooled and fallen around the vent.

9. CERRO NEGRO The Earth's most historically active cinder cone is Cerro Negro in Nicaragua. It is a very new volcano, the youngest in Central America. Since its birth in 1850, it has erupted approximately 20 times.

10. COMPOSITE VOLCANOES Composite volcanoes are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from high-viscosity lava, ash and rock debris. They are also called Stratovolcanoes. Mt. Rainier and Mount St. Helens are examples of this type of volcano.

11. MOUNT ST. HELENS Mount St. Helens is an active stratovolcano located in Washington. Mount St. Helens is most notorious for its major 1980 eruption, the deadliest and most economically destructive volcanic event in the history of the United States.

12. SHIELD VOLCANOES Shield volcanoes are volcanoes shaped like a bowl or shield in the middle with long gentle slopes made by basaltic lava flows. Basalt lava flows from these volcanoes are called flood basalts. The volcanoes that formed the basalt of the Columbia Plateau were shield volcanoes. Perhaps the best known shield volcanoes are the ones that make up the Hawaiian Islands, especially Mauna Loa and Mauna Kea.

13. MAUNA LOA The world’s largest active volcano Mauna Loa is located in Hawaii. From its base below sea level to its summit, Mauna Loa is taller than Mount Everest. It was one of the most active: Mauna Loa erupted 33 times between 1843 and 1984. It has been silent for more than 30 years now.

14. LAVA DOMES Lava domes are formed when erupting lava is too thick to flow and makes a steep-sided mound as the lava piles up near the volcanic vent. A volcanic dome often forms inside a crater following an explosive eruption. The eruption of Mount St. Helens in 1980 was caused in part by a lava dome shifting to allow explosive gas and steam to escape from inside the mountain..

15. MOUNT ST. HELENS LAVA DOME This lava dome started developing shortly after the iconic May, 18th 1980 eruption and dome growth continued until 1986

16. WHAT ARE DIFFERENT PARTS OF VOLCANO. MAGMA CHAMBER VENT CRATER CALDERA

17. MAGMA CHAMBER A magma chamber is the area beneath a volcano where magma collects before an eruption. Magma chambers are under such great pressure that, over time, they can eventually break the rock surrounding because they are less dense, creating a way for the magma to move upward.

18. VENT Magma emerges from the magma chamber of a volcano through openings called vents. Volcanoes often have one large vent called the main vent, from which most of the magma erupts.

19. CRATER A volcanic crater is a roughly circular depression in the ground caused by volcanic activity. It is typically a bowl- shaped feature within which occurs a vent or vents. This is where the lava, ash and rock erupt out of a volcano.

20. CALDERA Magma is stored beneath a volcano in a magma chamber. When a very large explosive eruption occurs which empties the magma chamber, the roof of the magma chamber can collapse forming a depression, or bowl on the surface which has very steep walls. The resultant landform is a vast circular pit that usually fills partly with water to form a deep lake, called Caldera Lake. These are calderas and can be tens of miles across. An example of a caldera is Yellowstone in North America.

21. PARTS OF A VOLCANO

22. WHAT IS THE DIFFERENCE BETWEEN LAVA AND MAGMA? MAGMA is the hot molten material occurring naturally below the surface of the earth. LAVA is the hot molten material on the surface of earth erupted through volcanoes. Fresh lava glows red hot to white hot as it flows.

23. LOCATION OF ACTIVE VOLCANOES Pacific Ring of Fire Mediterranean Belt

24. PACIFIC RING OF FIRE The Pacific Ring of Fire is an arc around the Pacific Ocean where many volcanoes and earthquakes are formed. Its edges mark a circle of high volcanic and seismic activity (earthquakes). 452 dormant and active volcanoes of the world are located in the region, which is 75% of the total number of volcanoes in the world. Some of the world’s most active volcanoes are found here. About 90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire. The Ring of Fire is sometimes called the Circum-Pacific belt. The Pacific Ring of Fire wraps around the Pacific Ocean, including the western coasts of the Americas, the islands of Japan, the Philippines, Canada, New Zealand and Indonesia.

25. PACIFIC RING OF FIRE

26. MEDITERRANEAN BELT Mediterranean Belt is the second major volcano belt. This region is not as large as the Pacific Ring of Fire. About 20% of all active volcanoes are in the Mediterranean belt, 20% are at or near mid- oceanic ridges. The Mediterranean Belt includes volcanoes in Italy, such as Mount Etna and Mount Vesuvius. Its general outlines correspond to the boundaries between the Eurasian, African, and Arabian plates.

27. The top map shows earthquakes that have occurred in the past 2500 years in the Mediterranean region. The lower map shows volcano sites in the same region.