Volcanoes: Science Orals Notes PDF

**VOLCANO -** Forms when magma (molten rock) rises from the earth's crust and erupts - **Like a mountain that has magma inside** - **NOTE: Volcanoes are cone-shaped, formed by the accumulation of lava and ash** ** Why do they erupt?** - Volcanic eruptions are powerful natural events t...

**VOLCANO -** Forms when magma (molten rock) rises from the earth's crust and erupts - **Like a mountain that has magma inside** - **NOTE: Volcanoes are cone-shaped, formed by the accumulation of lava and ash** ** Why do they erupt?** - Volcanic eruptions are powerful natural events that shape our planet - Occurs when molten rock, known as magma, rises to Earth's surface - magma then erupts, releasing a mixture of hot gases, ash, and molten rock, creating spectacular and sometimes dangerous displays. **PARTS OF A VOLCANO:** 1. - collects and supplies magma during eruptions - underground pool of molten rock (contains molten rock) 2. - Contains dissolved gasses and crystals - - 2 classifications: - - - 3 types: igneous rocks - - - 3. - Magma, gases, volcanic ash escapes to surface/pathway of magma going up - **NOTE:** Has **main vent** (summit), **side vents** (slopes) 4. **Conduit** - pathway of magma to the surface 5. - Forms from explosive eruption or when vent collapses - Bowl shaped depression 6. - Cools and solidifies when exposed to air (forms new rock layers) 7. **Caldera** - Large, basin-shaped depression - Forms when summit/side of volcano collapse after massive eruption (empties magma chamber) - Fills with water to form lakes - **TYPES OF VOLCANOES:** 1. - **Explosive eruptions (andesitic/rhyolitic magma)** - **VERY EXPLOSIVE; SUBDUCTION ZONES** 2. - Formed by highly fluid lava flow - Effusive eruption, non-explosive (basaltic) - LONG-LASTING, CALM 3. - Formed by accumulation of ***cinder*** (volcanic fragments) - Short-lived explosive eruptions - SIMPLEST; CLUSTERS **TYPES OF VOLCANIC ERUPTIONS:** 1. - Lava fountains, slow moving lava flow - Creates shield volcanoes 2. - Extremely violent - Powerful blast waves and pyroclastic flow 3. - Extremely dangerous - Release large amounts of steam and ash **VOLCANIC ACTIVITY AND PLATE TECTONICS:** **Plate Boundaries** - Area where tectonic plates move - Volcanoes usually form here  - 2 types: 1. - Plates move apart - Magma rises from mantle to create volcanoes 2. - Plates collide - 1 plate may be above the other plate - **MONITORING VOLCANOES (before eruption):** 1. **Seismicity -** Increased seismic activity before an eruption - **can include earthquakes, tremors, and harmonic tremors** 2. **Gas Emissions -** Release more gases (sulfur dioxide, carbon dioxide) 3. **Ground Deformation -** Changes in ground elevation or tilt (indicates magma movement) 4. **Thermal Monitoring -** Increased heat flow (magma rising) 5. **Monitoring - uses tools to track volcanic activity: Seismometers, Gas detectors, GPS** 6. **Research** - Study volcanoes to: a. Learn earth's internal process b. Develop strategies to mitigate risks 7. **Prediction** - Monitoring helps understand volcanic behavior - **Warns people about potential hazards** **CAUSES OF ERUPTION:** **1. Pressure Build-up** - Magma rises from the Earth\'s mantle, accumulating in a magma chamber. **2. Gas Expansion** - magma contains dissolved gases (primarily water vapor) that expand as pressure decreases. **3. Fractures** - The pressure from expanding gases and rising magma can fracture the surrounding rock, providing pathways for eruption. **MAGMA AND PRESSURE BUILD-UP:** 1. 2. - Makes force of eruption stronger 3. **Gases and explosive eruptions:** ** HIGH** gas content = **EXPLOSIVE** eruptions ** LOW** gas content = **EFFUSIVE** eruptions **VOLCANIC HAZARDS:** 1. **Ash -** Fine-grained rock fragment - Ejected in atmosphere during eruption - Causes respiratory problems and damage infrastructure 2. **Lava Flows -** Streams of molten rock that can travel in long distances - Destroys everything in its path - Speed and distance depend on viscosity of lava 3. **Pyroclastic Density Currents -** Fast-moving mixtures of hot gas and volcanic debris - Travels more than 100 km/h 4. **Ashfall** - disrupts transportation, agriculture, power systems **EVACUATION & EMERGENCY RESPONSE PLANS:** 1. **Evacuation Orders -** Issued when eruption is imminent, vital for protecting lives 2. **Emergency Shelters -** Designated locations where people can evacuate to - Safe and has essential supplies 3. **Emergency Response Teams -** Trained professionals who respond to volcanic emergencies - Handles evacuations to rescue operations **DISASTER MITIGATION:** 1. **Building Codes -** Makes structures stronger against ash, lava, etc. 2. **Evacuation Routes -** Clear routes make sure people can safely evacuate 3. **Communication Systems -** Helps share info and warnings about volcanic activity 4. **Public Awareness -** Educate public about volcanic hazards and emergency preparedness - - - a. b. c. d. ○ Wells are drilled into the geothermal reservoirs to access steam or hot water. **Advantages of Geothermal Energy from Volcanoes** **Challenges of Geothermal Energy from Volcanoes** **7.1 Monitoring and Early Warning** **Plate Boundaries - pacific, north, south American, Eurasian, indo-australian plate** **Pyroclastic Materials - Fragmented materials ejected during an explosive eruption (ash, tephra, etc.)** **Volcanic Gases - Gases released during eruption**