Earth's Plates and Plate Tectonics

• The Earth's highest and deepest points were formed by plate movements
• The lesson objectives are to understand plate movements, identify earthquake hazards, recognize tsunami signs, analyze effects, interpret hazard maps, and apply safety measures
• The Earth is composed of the core, mantle, and crust

Earth Layers

• The core is the Earth's hottest, innermost layer
• The mantle is the thick second layer
• The crust is the thinner layer covering the mantle

Asthenosphere and Lithosphere

• Asthenosphere: The hotter and more easily deformed inner layer
• Lithosphere: The outer layer composed of large blocks called tectonic plates

Plate Tectonics Theory

• The Earth is divided into plates.
• Plates are like slabs on the surface of the Earth's shell or lithosphere
• All land and water sit on these plates
• Plates are constantly in motion
• Earth's plates move around the surface at a rate of a few centimeters every year

Subduction Zones

• Subduction zones are areas where tectonic plates converge

Earthquake

• Earthquake: Perceptible shaking of the Earth's surface from a sudden energy release in the crust creating seismic waves
• Source: United States Geological Science (USGS)

Earthquake Hazards

• Earthquake hazard: Potential dangers and destructive effects caused by earthquakes

Primary Earthquake Hazards

• Ground shaking
• Landslides
• Liquefaction
• Surface rupture

Secondary Earthquake Hazards

• Tsunami
• Seiche
• Flooding
• Fire

Intensity and Magnitude of an Earthquake

• Intensity: Perceived strength based on the earthquake's relative effect on people and structures
• Magnitude: Based on instrumentally derived information correlated with total energy released at the earthquake's origin

Earthquake Measurement Scales

• Mercalli Intensity Scale: Developed by Giuseppe Mercalli in 1902
• Richter Magnitude Scale: Developed by Charles F. Richter in 1935
• Moment Magnitude Scale: Developed in the late 20th century

Hazard Maps

• Hazard map: A visual representation of areas at risk from natural hazards

Earthquake Preparedness Measures

• Know Your Risk: Check earthquake hazard maps to understand your area's risk level
• Secure Heavy Objects: Bolt furniture, shelves, and heavy appliances to walls
• Create an Emergency Kit: Include water, food, first aid supplies, flashlight, batteries, and important documents
• Develop an Emergency Plan: Discuss safe exits, meeting points, and communication plans with family members
• Reinforce Buildings: Strengthen your home or workplace to make it more earthquake-resistant
• Identify Safe Spots: Find sturdy furniture (like tables) or interior walls to take cover under
• Participate in Drills: Practice "Drop, Cover, and Hold On" regularly

Response Measures During an Earthquake

• If Indoors: Drop, Cover, and Hold On
• Get down, take cover under a sturdy table, and hold on
• Stay Indoors: Move away from windows, glass, and objects that could fall
• Avoid Doorways: Door frames are not the safest place; protect yourself under a strong table
• If Outdoors: Move to an Open Area and stay away from buildings, trees, streetlights, and power lines
• Drop to the Ground and stay low, protecting your head from falling debris
• If in a Vehicle: Pull Over Safely and stop in a clear area away from bridges, overpasses, and buildings
• Stay Inside the Vehicle and wait until the shaking stops before driving carefully

Recovery Measures After an Earthquake

• Check for Injuries and administer first aid if needed, and call for emergency help
• Inspect for Hazards: Look for structural damage, gas leaks, and electrical issues
• Turn Off Utilities if Necessary and shut off gas, electricity, and water if there are leaks or damage
• Be Aware of Aftershocks because smaller quakes may follow, stay alert and take cover if needed
• Follow Official Updates and listen to emergency broadcasts and obey evacuation orders if given
• Stay Away from Damaged Areas and don't enter unstable buildings or areas prone to landslides
• Help Others: Assist neighbors, especially children, elderly, and injured individuals