This unit teaches you to read a tectonic city and design buildings, codes, and policies that protect people from earthquakes, volcanoes, and tsunamis. You will defend a city hazard profile and engineering portfolio. The vocabulary below is the precise language you will use in your design rationales and defenses.
Vocabulary
| Term | What it means + visual cue | Sentence stem |
|---|---|---|
| Tectonic plate | A large slab of Earth's lithosphere that moves slowly over the mantle. Visual: Jigsaw puzzle pieces fitting together on a globe. | This city sits on the ___ plate, which is ___. |
| Convergent boundary | Where two plates move toward each other. Produces mountains, volcanoes, and earthquakes. Visual: Two arrows pushing toward each other; plate pushed upward. | This is a convergent boundary because ___. |
| Divergent boundary | Where two plates move apart. Produces mid-ocean ridges and rift valleys. Visual: Two arrows pulling apart; new crust filling the gap. | This is a divergent boundary because ___. |
| Transform boundary | Where two plates slide past each other horizontally. Produces strike-slip earthquakes (e.g., San Andreas). Visual: Two arrows sliding past each other horizontally. | This is a transform boundary because ___. |
| Subduction | When one tectonic plate sinks beneath another at a convergent boundary. Causes the largest earthquakes and tsunamis. Visual: One plate diving under another into the mantle. | Subduction at this margin produces ___. |
| Fault | A fracture in the Earth's crust along which movement has occurred. Major source of earthquakes. Visual: Cracked rock with arrows showing slip direction. | The ___ fault runs through this city, capable of ___. |
| Magnitude | A measure of an earthquake's size at its source. Logarithmic scale: each whole number = 10× ground motion. Visual: Bar chart with M5, M6, M7 bars increasing exponentially. | An earthquake of magnitude ___ at this fault would ___. |
| Intensity | A measure of an earthquake's effects at a specific location. Depends on magnitude, distance, soil, and building type. Visual: Same earthquake felt as I (light) far away and IX (violent) nearby. | Intensity at this site would be ___ because ___. |
| Hazard | A natural event that can cause harm: earthquake, tsunami, eruption. The event itself. Visual: Warning triangle with wave inside. | The primary hazard at this site is ___. |
| Vulnerability | How exposed and unprepared people, buildings, and systems are to a hazard. The harm done depends on vulnerability, not just the hazard. Visual: Same earthquake hitting a wood shack vs. a reinforced building. | Vulnerability at this site is high / low because ___. |
| Risk | The combination of hazard and vulnerability. Risk = (probability of hazard) × (consequences if it happens). Visual: Equation: Hazard × Vulnerability = Risk. | The seismic risk here is ___ because ___. |
| Resilience | The ability of a city, community, or system to absorb a hazard and recover quickly. Visual: Bouncing ball returning to shape after impact. | To build resilience, this city should ___. |
| Mitigation | Actions taken before a hazard to reduce its impact: building codes, land-use planning, early warning systems. Visual: Shield in front of incoming hazard. | A key mitigation measure here would be ___. |
| Retrofit | Modifying an existing building or structure to make it safer against future hazards. Visual: Cross-section of old building with new steel braces added. | Retrofitting this building would involve ___. |
| Building code | The set of rules that buildings in a region must follow. Earthquake-prone regions require seismic codes. Visual: Rulebook with construction icon. | This city's building code should require ___. |
| Return period | The average time between events of a given magnitude (e.g., a 500-year flood). NOT a guarantee: events can happen earlier. Visual: Calendar marked with widely-spaced X marks. | The return period for a magnitude ___ event here is about ___. |
| Engineering trade-off | When making one part of a design better makes another part worse. Cost vs. safety, stiffness vs. flexibility, etc. Visual: Seesaw with cost on one side, safety on the other. | A trade-off in this design is ___ vs. ___. |
Hazard mapping. I will show you a city map with hazard zones unlabeled. In pairs, label as many hazard zones as you can using vocabulary from this list, and propose one mitigation action per zone.
With a partner: pick one of the U3 Defense Panel role-cards. Practice answering one question from your panelist's perspective using at least 5 terms from this list. Your partner critiques: did you use the terms precisely, or just dropped them in?
Multilingual reference
For translations of these terms into Tamil, Hindi, French, Korean, or Japanese, see the Master Vocabulary Reference: U3 section. The five-column translation tables there are an AI-assisted starting reference: verify with a native-speaker peer or teacher when precision matters.
If you would like to discuss any of these terms in your first language with an AI tutor, you may. Document that use in the AI Documentation section of any assessment that follows. See the AI Documentation Protocol.