Volcanoes Science PDF

Summit is the highest part of the volcano Slope is the side part of the volcano Base is the lowest part of the volcano Crater is the opening at the top of the volcano Caldera is larger than the crater, it forms when part of the wall collapses. Volcanoes are a natural opening in the earth's surf...

Summit is the highest part of the volcano Slope is the side part of the volcano Base is the lowest part of the volcano Crater is the opening at the top of the volcano Caldera is larger than the crater, it forms when part of the wall collapses. Volcanoes are a natural opening in the earth's surface where molten rocks, smoke, gases, and ashes are ejected. The 10 active volcanoes are Kanlaon, Mayon, Pinatubo, Taal, Bulusan Iraya, Hibok-Hibok, Banahaw, Ragang, and Makaturing. The inactive ones are Cabaluyan, Cocoro, Urot, Tamburok There are 300 volcanoes in the Philippines, 23 of them are active while 277 are inactive. Philippine Institute of Volcanology and Seismology or PHIVOLCS classifies volcanic activity into active or inactive. Magma are molten rocks inside the earth while Lava are magmas that has been ejected out of the volcano There are 3 types of Volcano 1. Shield Volcano- non explosive, very less sticky, flows out in all directions, have a long gentle slope like a warrior shield. 2.Cinder Cone Volcano- Have a sticky fragmented lava that settles around the volcanos mouth forming an oval or circular cone. 3.Composite Volcano- Have a very sticky lava that is too slow forming a columnar pile in the vent, gives the reason to be described as "almost perfect or perfect cone" There are 5 types of Volcanic Eruption 1. Strombolian eruption- erratic generally relatively small explosion or weak pulsation explosion. 2. Phreatic eruption- happens when underground water or surface water is heated by magma. 3. Phreatomagmatic eruption- interaction between water and magma. 4. Vulcanian eruption- a dense cloud of gas loaded with ash explodes from the crater and rises high above its peak. 5. Plinian eruption- a powerful and violent eruption, may produce a sound like a bomb to an end. 3 factors affecting the volcanoes eruptive style. 1. Magma's Temperature 2. Chemical Composition 3. Amount of gasses 1. Temperature: High temperature magma flows easily therefore has low viscosity Low temperature magma resist flow therefore has high viscosity Viscosity is defined as the property of the materials resistance to flow it is also described as liquids thickness stickiness semi fluid 2. Chemical composition Magma's resistance to flow is a function of its internal friction derived from the chemical bonds within the liquid Oxygen and silicon- these are the important factor in determining the degree of magma's viscosity 3. Amount of Gases All magmas contain gases that gives their explosive character, the gas will increase as pressure reduces 1. Lava with less silica content has low viscosity that it can travel a great distance, forming a thin sheet 2. Lava with high silica content is to viscous to travel far, tends to break up as it flows 3. Lava with low amount of gas and high silica content is very viscous and does not flow out at all as it rises forming a columnar plug in the vent 4. Lava with low amount of gas as it rises has high viscosity that it piles up at event resulting in a dome Volcanoes Materials Emission Magma is a mixture of minerals and contains dissolved gases such as: water vapor carbon dioxide and sulfur. 3 types of Magma 1. Mafic or basaltic magma Is not viscous and will flow easily to the surface it is high in iron magnesium and calcium but low in potassium and sodium with silicon dioxide its temperature ranges from about 1,000° c to 1,200° c 2. Intermediate or andesitic magma It is moderate in iron magnesium calcium sodium and potassium with silicon dioxide temperature ranges from about 800° c to 1,000° c 3. Felsic or rhyolitic magma It is viscous and does not flow easily it is high in potassium and sodium but low in iron magnesium and calcium with silicon dioxide the temperature ranges from about 650°c to 800° c Pyroclastic material Is cloud ash lava fragments carried through the air and vapor the hot broken fragments is called pyroclasts 12 types of if igneous rocks 1. Basalt 2. Pumice 3. Obsidian 4. Rhyolite 5. Scoria 6. Dacite 7. Granite 8. Gabbro 9. Diabase 10. Diorite 11. Pegmatite 12. Peridotite