Volcanoes Notes PDF

Here are the summarized notes from the PowerPoint presentations: Week 1: Volcanoes (Unit 1) What is a Volcano? ​ An opening in a planet's crust from which molten rock, ash, and gases escape. ​ Examples: Mount Tavurvur (Papua New Guinea) and Mayon Volcano (Philippines). Classification of Vo...

Here are the summarized notes from the PowerPoint presentations: Week 1: Volcanoes (Unit 1) What is a Volcano? ​ An opening in a planet's crust from which molten rock, ash, and gases escape. ​ Examples: Mount Tavurvur (Papua New Guinea) and Mayon Volcano (Philippines). Classification of Volcanoes ​ Active: Erupted in the last 10,000 years; shows signs of activity. ​ Inactive (Dormant): volcanoes who have long been thought to be extinct but suddenly resumed eruption lately. a volcano that has not erupted in a long time, but could erupt again. ​ Extinct: No eruption since historical times; unlikely to erupt again. Magam supply depleted Types of Volcanoes 1.​ Composite (Stratovolcano): ○​ Tall mountain with crater on top with high silica content lava. ○​ Pyroclastic materials ○​ Known for violent eruptions ○​ Example: Mayon Volcano. 2.​ Shield Volcano: ○​ Flat and broad, with low-silica lava. ○​ Examples: Mauna Loa, Kilauea. 3.​ Cinder Cone: ○​ Small, steep slopes of pyroclastic material. ○​ They often form in groups near a large volcano. Most of them usually erupt only once. ○​ Example: Paricutin (Mexico), Jolo (Philippines). Volcanic Eruptions ​ Effusive Lava ​ Lava is molten rock erupted at the ground surface. When molten rock is beneath the ground, it is called magma. ​ Lava flows are the effusive (non-explosive) outpourings of lava, and usually flow slower than walking pace. Lava flow types include a’a, blocky and pahoehoe. ​ Lava fountains are a fountain of runny lava fragments from a vent or line of vents (a fissure). They can form spatter piles, and if the fragments accumulate fast enough, they can form lava flows. ​ Lava domes are mounds that form when viscous lava is erupted slowly and piles up over the vent, rather than moving away as a lava flow. They are generally caused by  viscous, thick, sticky lava that has lost most of its gas. They can range in volume from a few cubic metres to cubic kilometres. ​ Explosive Types: ○​ Hydrothermal: Driven by water interaction. An eruption driven by the heat in a hydrothermal systems (Superheated water turns into steam). Hydrothermal eruptions pulverize surrounding rocks and can produce ash, but do not include magma. ○​ Phreatic: An eruption driven by the heat in a hydrothermal systems. (Water is heated by magma) Hydrothermal eruptions pulverize surrounding rocks and can produce ash, but do not include magma. ○​ Phreatomagmatic eruption: An eruption resulting from the interaction of new magma or lava with water and can be very explosive. The water can be from groundwater, hydrothermal systems, surface runoff, a lake or the sea. ○​ Strombolian and Hawaiian eruptions: These are the least violent types of explosive eruptions. Hawaiian eruptions have fire fountains and lava flows, whereas Strombolian eruptions have explosions causing a shower of lava fragments. ○​ Vulcanian eruptions are small to moderate explosive eruptions, lasting seconds to minutes. Ash columns can be up to 20 km in height, and lava blocks and bombs may be ejected from the vent. ○​ Subplinian and Plinian eruptions: Eruptions with a high rate of magma discharge, sustained for minutes to hours. They form a tall, convective eruption column of a mixture of gas and rock particles, and can cause wide dispersion of ash. Subplinian eruption columns are up to 20 km high, and are relatively unsteady, whereas Plinian eruptions have 20 to 35 km tall columns which may collapse to form pyroclastic density currents (PDC’s). Very rare Ultraplinian eruptions are even larger and have a higher magma discharge rate than Plinian eruptions. Week 2: Effects and Energy from Volcanoes Hazards of Volcanic Eruptions ​ Ash: Disrupts air travel, damages respiratory health. ​ Gases: Affect global temperatures and can form acid rain. ​ Lava flows, Poisonous gases, Flattened landscapes, Lowering atmospheric temperature ​ Extremely hot lava flows destroy everything in its path, is made up of molten rock from the volcano ​ Lahar – a fast moving mudflow that includes all debris along its path (river valley), composed of vey thick slurry pyroclastic material, rock debris and water. ​ It can bury towns and wipe out a forest, so tress burn up and fall like matchsticks. ​ It produces a sound like rolling thunder. ​ Volcanic ash fall: Can actually be abrasive, acidic, and odorous. This can cause lung damage in infants, the elderly, and those who have respiratory illnesses.  ​ Acidic ash Can damage electrical and mechanical equipment. It can also mix with rain and collapse roofs. ​ Secondary effects: Earthquakes, landslides, fires, and flash floods. Beneficial Effects ​ Fertile soil from weathered volcanic materials. ​ Creation of new landforms (e.g., islands, land extensions). Energy from Volcanoes ​ Geothermal energy: Heat from Earth's interior is used to generate electricity. ​ Applications: Hot springs, aquaculture (e.g., prawn farming). ​ The Philippines is a top geothermal energy producer due to its location in the Pacific Ring of Fire. ​ Hot water for Raising prawns Week 3: Lava Flow and Volcano Locations Earth’s Layers ​ Crust: Outermost solid layer; thinner under oceans (10 km) than continents (35 km). ​ Mantle: Contains the lithosphere (solid upper mantle and crust) and asthenosphere (molten rock enabling plate movement). ​ Much thicker portion estimated to be around 2885 km ​ Its chemical composition and physical properties are not uniform throughout. ​ It is divided into two: the lithosphere and asthenosphere ​ Lithosphere – it is constitutes by the crust and ​ the uppermost part of the mantle ​ Asthenosphere – Its temperature is much higher due to the pressure from the upper layers, the rocks are somewhat melted. ​ There is a certain part of asthenosphere where based from the earthquake data, scientists observe that seismic waves slow down as they pass through it. Why? -it is because of the molten rock in this part of the mantle. Within asthenosphere, temperature differences cause movement of the molten material. Molten material beneath the lithosphere is relatively less hot, and it slowly sinks. However, the hotter material below rises. Where are the volcanoes often found? Based on the discovery of the scientists, they explained that it is based on the theory of plate tectonics. This theory holds that the earth’s lithosphere is broken into a number of segments or plates, and these plates are in motion. Plate Tectonics and Volcanoes ​ Divergent Boundaries: Plates move apart, forming mid-ocean ridges and submarine volcanoes. ○​ Examples: Mid-Atlantic Ridge. ​ Convergent Boundaries: Plates collide, forming trenches, volcanoes, and islands. ○​ Example: Philippine Trench and Pacific Ring of Fire. Volcanoes in Plate Interiors ​ Many volcanoes are also found in convergent plate boundaries. Examples are the volcanoes in the “Pacific Ring of Fire.” ​ Some form away from plate boundaries due to hotspots in the Earth's mantle. Week 4: Weather Vs Climate Weather and Climate ​ Weather: Short-term atmospheric conditions. It pertains to the day’s condition of the air. ​ Climate: It pertains to the average condition of the atmosphere in a region over a period of many years in terms of the same elements as those of weather. ​ Weather Instruments: Refer to the table in source and for a list of instruments and their functions. Weather Instruments Function Thermometer An instrument that measures temperature (Celsius, Fahrenheit, Kelvin) Mercury barometer Used to calibrate and check aneroid barometers (Atmospheric pressure or altitude above sea level) Aneroid barometer An instrument used for measuring air pressure as a method that does not involve liquid Barograph Instrument used to make a continuous recording of atmospheric pressure Anemometer Instruments that measures wind speed and wind pressure Wind vane It is used for indicating wind direction (One of oldest meteorological instruments) Sling psychrometer Can be used to find relative humidity (Expressed as percentage, moisture of air)  Hygrograph Hair hygrograph is a hair hygrometer to which a clock-driven drum is installed to record humidity no a recording chart Rain gauge Collects water falling on it and records the change over time in the rainfall depth (mm) Radiosonde It measure altitude, pressure, temperature, relative humidity, wind, cosmic ray at high altitudes Radar It can detect surrounding objects using radio waves ​ In the Philippines, the government agency in charge of monitoring the changes in atmospheric properties is the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) under the Department of Science and Technology (DOST). ​ Factors Affecting Global Climate i.e. Increase the global warming Influenced by interactions involving the Sun, ocean, atmosphere, land, clouds, ice and living things. Global surfaces temperatures (C°) through the years as affected by activities of the Sun (solar); by volcanic activities (volcano); by people (anthropogenic), like pollution; and by the El Niño/Southern Oscillation (ENSO). The HadCRUT is a monthly data set compiled from temperature observations over land and sea since 1850. ○​ Natural Factors: ​ Solar activities (irradiance, magnetic field, UV radiation). ​ Cloud cover (However, water vapor in clouds also acts as a greenhouse gas, trapping some heat and bounces it back to the earth.). ​ Forest fires (Wild forest fires release carbon dioxide into the atmosphere. This is one of the greenhouse gases that trap heat in the atmosphere. The more forest fires, more carbon dioxide contributes to global warming by trapping heat in the atmosphere. ). ​ Volcanic eruptions (release greenhouse gases that contribute to global warming and when gas and ash interact with water sulfuric acid is spread which cool the atmosphere). ​ El Niño phenomenon (causes extreme weather conditions Some affected elements aside from temperature, all other elements of weather and climate). ​ Oceans (absorb and distribute heat, act as carbon sinks). ○​ Anthropogenic (Human) Activities: ​ Burning fossil fuels (releases greenhouse gases). ​ Deforestation (reduces carbon dioxide absorption). ​ Waste disposal and industrial practices (release greenhouse gases methane and nitrous oxide). ​ Electricity use (contributes to greenhouse gas emissions). Week 4: Climate Change ​ Carbon (C) is the basic building block of life, although many nonliving things also contain carbon. It is the fourth most common element in the universe. Organisms need carbon for structure, for energy, or both. Humans use carbon for both. Carbon Cycle ​ Before plants or animals consume carbon, it is part of the earth’s atmosphere as a molecule of carbon dioxide. Humans, like all animals, release carbon dioxide when they exhale or go to the bathroom. When a living organism dies and decomposes, all its stored carbon is released into the ground. The carbon cycle shows that carbon moves between the atmosphere, the oceans, the biosphere (living things) and the geosphere (sediments, rocks and fossil fuels). ​ All the living things that add carbon to the atmosphere are called “source”. All things that remove carbon from the atmosphere are called “sink”. ​ Plants use carbon dioxide in the process of photosynthesis, producing sugar and oxygen as a by-product. Plants and animals use body sugars for energy to grow. As sugar is “burned” or used, some carbon is released back into the atmosphere as carbon dioxide in a process called respiration. Earth's Carbon Budget ​ All carbon produced by sources are taken up by sinks ​ Human burn fuels, therefore, carbon is released into the atmosphere. ​ If humans clear forests for agriculture, more carbon is released into the atmosphere. ​ Extra carbon contributes to global warming. The greenhouse effect is a natural phenomenon where heat-trapping gases in the atmosphere, such as water vapor and carbon dioxide, absorb the infrared (heat) radiated back by the earth’s surface. Enhanced Greenhouse effect It refers to the increased heat-retaining process in the atmosphere due to an usually large amount of carbon dioxide and other greenhouse gases resulting from air pollution and other environmental problems. The increased concentrations of some of these gases amplify or enhance the natural greenhouse effect. Greenhouse gases (carbon dioxide, methane, nitrous oxide and water vapor) act as a blanket that keeps the planet warm. In normal conditions, these gases keep the earth at 19°C instead of an extremely cold -14°C. However, because of too much greenhouse gases, there has been an enormous amount of heat trapped in our atmosphere. Over so many years, the amount of greenhouse gases within the atmosphere has been rapidly increasing. Global warming It is refers to the marked increase in ambient temperature brought about by the release of greenhouse gases into the earth’s atmosphere. When the amount of heat enters the atmosphere changes, or when the amount of heat that leaves the atmosphere changes, climate is affected on a global scale. Thus, global warming can occur because of an increased amount of heat entering the earth or decreased amount of heat that escapes the earth’s atmosphere. Some time at the beginning of the 20th century, Svante August Arrhenius (1859-1927), a Swedish physicist and chemist, researched on the possible effects of an increase in atmospheric carbon dioxide on global climate. About 50 years later, a study by an American geophysicist by the name of Roger Revelle showed that atmospheric carbon dioxide actually increased due to the use of fossil fuels. Revelle became a member of the U.S. government committee which predicted the possibility of global warming by carbon dioxide. Climate Change It is a long range change in patterns of temperature, wind and precipitation of a certain region or of the entire planet. Climate change may be due to different factors, which include natural processes and human activities. What is the relation between global warming and climate change? Among the elements of weather and climate are temperature and precipitation. Global warming contributes to climate change. It is therefore necessary for us to be proactive in trying to reduce greenhouse gas emissions (GHG) and adapt these methods to reduce the impact of climate change. It is important to take steps to reduce carbon emissions and to prepare to adapt to the impact of climate change.