Impacts on people and the environment: short-term impacts and long-term impacts

🌍 Earthquakes are like a giant drum that suddenly starts beating. The ground shakes, buildings sway, and people can feel the tremor.

• 💥 Immediate injuries from falling objects or collapsed structures.
• 🚑 Emergency services struggle to reach trapped victims.
• 🏚️ Buildings can collapse, especially older or poorly built ones.
• 🛑 Power, water and gas lines may break, causing fires or floods.

⚠️ Key point: The shaking stops quickly, but the damage can be huge.

🌋 Volcanoes are like a boiling pot that suddenly erupts. Ash, lava, and gases are thrown into the air.

• 🌫️ Ash falls on roofs, causing them to collapse.
• 🔥 Lava flows destroy everything in its path.
• 💨 Toxic gases can cause respiratory problems.
• 🚨 Evacuation is often required; roads can be blocked by ash.

⚠️ Key point: The eruption can happen in minutes, giving little warning.

🌍 Earthquakes can reshape landscapes for years.

• 🗻 Fault lines may shift, creating new hills or valleys.
• 🏠 Rebuilding can take years; homes may be redesigned to be quake‑resistant.
• 💰 Economic costs: loss of jobs, damaged infrastructure.
• 🧠 Psychological trauma can persist for decades.

🌋 Volcanoes leave lasting changes.

• 🌱 New fertile soil forms from ash, boosting agriculture after a decade.
• 🏞️ Landscapes change: new craters, lava fields, and altered rivers.
• 💸 Tourism can increase or decrease depending on safety.
• 🧪 Scientific research opportunities arise from studying new geology.

Remember: Use the cause–effect structure in answers.

1. Start with the hazard (earthquake or volcano).
2. List short‑term impacts on people, infrastructure, and environment.
3. Explain long‑term impacts and how societies adapt.
4. Use examples (e.g., 2011 Tōhoku earthquake, 1980 Mount St. Helens).

📚 Formula to remember: Seismic energy: $E = \frac{1}{2}\mu \omega^2 A^2$

📚 Volcanic magnitude: $M_w = \frac{2}{3}\log_{10}E - 4.8$