18  Performance Task: Natural Hazard Risk Assessment

Argue whether your location’s benefits outweigh its hazard risks

HS-ESS1-5 HS-ESS2-1 HS-ESS2-3 HS-ESS3-1 Performance Task

🌍 Should 3 Million People Be Living Next to Vesuvius?

19 The Challenge

Your task is to select a real location near a plate boundary and develop a scientific argument about whether the natural hazard risks at that location outweigh the benefits — or vice versa.

This is not a question with one right answer. What matters is the quality of your evidence and reasoning.

Plot = require("@observablehq/plot")
d3 = require("d3@7")

20 🔍 Evidence Review — What You’ve Learned

20.1 Chapter 1: Earth’s Interior

Key Evidence Available:

• Earth has a layered structure: crust, mantle, outer core, inner core
• We know this from seismic wave analysis (P-waves and S-waves)
• The mantle is solid but flows slowly over millions of years
• Earth’s layers formed through density differentiation — denser materials sank to the center
• Processes deep inside Earth ultimately cause surface events

20.2 Chapter 2: Plate Boundaries & Surface Features

Key Evidence Available:

• Three types of boundaries: divergent (pull apart), convergent (push together), transform (slide past)
• Earthquakes cluster along plate boundaries — not random
• Seafloor spreading creates new crust at mid-ocean ridges
• Subduction zones produce the most violent volcanic eruptions
• Evidence for plate motion: magnetic striping, fossil distribution, continent shapes, seafloor ages
• Some features (like the Adirondacks) exist far from boundaries — remnants of ancient tectonic events

20.3 Chapter 3: Energy & Matter

Key Evidence Available:

• Earth’s interior produces 47 terawatts of heat (radioactive decay + primordial heat + core crystallization)
• Convection in the mantle is the engine that drives plate motion
• The same tectonic processes that cause hazards also create resources: fertile soil, minerals, geothermal energy
• About 500 million people live near active volcanoes worldwide
• Risk and benefit are often inseparable at plate boundaries

21 📊 Interactive Risk Assessment Tool

viewof selectedLocation = Inputs.select(
  ["Naples, Italy (Vesuvius)", "Tokyo, Japan", "San Francisco, USA", "Reykjavik, Iceland", "Jakarta, Indonesia", "Santiago, Chile", "Kathmandu, Nepal", "Mexico City, Mexico"],
  {label: "🗺️ Choose your location:"}
)

locationData = ({
  "Naples, Italy (Vesuvius)": {
    boundary: "Convergent (African Plate subducting under Eurasian Plate)",
    population: "3 million in danger zone",
    hazards: [{name: "Volcanic eruption", risk: 9}, {name: "Earthquake", risk: 7}, {name: "Pyroclastic flows", risk: 10}, {name: "Tsunami", risk: 5}, {name: "Ash fall", risk: 8}],
    benefits: [{name: "Fertile volcanic soil", value: 9}, {name: "Geothermal energy", value: 6}, {name: "Tourism", value: 8}, {name: "Mineral deposits", value: 5}, {name: "Cultural heritage", value: 10}],
    history: "79 CE: Vesuvius destroyed Pompeii and Herculaneum, killing ~16,000. Last eruption: 1944. Scientists say it WILL erupt again.",
    lat: 40.8, lon: 14.3
  },
  "Tokyo, Japan": {
    boundary: "Triple junction (Pacific, Philippine Sea, North American plates)",
    population: "37 million in metro area",
    hazards: [{name: "Earthquake (M7-9)", risk: 10}, {name: "Tsunami", risk: 9}, {name: "Volcanic eruption (Mt. Fuji)", risk: 6}, {name: "Ground liquefaction", risk: 8}, {name: "Fire after earthquake", risk: 7}],
    benefits: [{name: "Geothermal energy", value: 8}, {name: "Hot springs (onsen)", value: 7}, {name: "Mineral resources", value: 6}, {name: "Fertile valleys", value: 7}, {name: "Natural harbors", value: 8}],
    history: "1923: Great Kanto earthquake killed 140,000. 2011: Tōhoku M9.0 caused Fukushima disaster. 70% chance of M7+ in next 30 years.",
    lat: 35.7, lon: 139.7
  },
  "San Francisco, USA": {
    boundary: "Transform (Pacific and North American plates — San Andreas Fault)",
    population: "4.7 million in Bay Area",
    hazards: [{name: "Earthquake (M6-8)", risk: 9}, {name: "Ground liquefaction", risk: 7}, {name: "Landslides", risk: 6}, {name: "Tsunamis (local)", risk: 4}, {name: "Fire after earthquake", risk: 7}],
    benefits: [{name: "Natural harbor", value: 9}, {name: "Fertile soil (Central Valley)", value: 8}, {name: "Gold & mineral deposits", value: 6}, {name: "Oil & natural gas", value: 5}, {name: "Unique landscape", value: 7}],
    history: "1906: M7.9 earthquake + fire destroyed 80% of city, killed 3,000. 1989: Loma Prieta M6.9. 72% chance of M6.7+ before 2043.",
    lat: 37.8, lon: -122.4
  },
  "Reykjavik, Iceland": {
    boundary: "Divergent (North American and Eurasian plates — Mid-Atlantic Ridge)",
    population: "230,000 in metro area",
    hazards: [{name: "Volcanic eruption", risk: 8}, {name: "Earthquake", risk: 5}, {name: "Glacial floods (jökulhlaups)", risk: 6}, {name: "Lava flows", risk: 7}, {name: "Ash disruption", risk: 7}],
    benefits: [{name: "Geothermal energy (87% heating!)", value: 10}, {name: "100% renewable electricity", value: 10}, {name: "Hot springs & tourism", value: 9}, {name: "Volcanic soil (greenhouses)", value: 6}, {name: "Fish-rich waters", value: 8}],
    history: "2010: Eyjafjallajökull grounded all European flights. 2021-present: Fagradalsfjall eruptions ongoing. But Iceland has turned geology into prosperity.",
    lat: 64.1, lon: -21.9
  },
  "Jakarta, Indonesia": {
    boundary: "Convergent (Indo-Australian Plate subducting under Eurasian Plate)",
    population: "31 million in metro area",
    hazards: [{name: "Earthquake", risk: 8}, {name: "Volcanic eruption", risk: 8}, {name: "Tsunami", risk: 9}, {name: "Ground subsidence", risk: 9}, {name: "Flooding", risk: 8}],
    benefits: [{name: "Volcanic soil fertility", value: 9}, {name: "Mineral deposits", value: 8}, {name: "Geothermal potential (27 GW)", value: 7}, {name: "Fisheries", value: 8}, {name: "Biodiversity", value: 9}],
    history: "2004: Indian Ocean tsunami killed 230,000 (mostly in Indonesia). 127 active volcanoes. Capital being relocated to Borneo due to sinking.",
    lat: -6.2, lon: 106.8
  },
  "Santiago, Chile": {
    boundary: "Convergent (Nazca Plate subducting under South American Plate)",
    population: "7 million in metro area",
    hazards: [{name: "Earthquake (M8-9.5!)", risk: 10}, {name: "Volcanic eruption", risk: 6}, {name: "Tsunami", risk: 7}, {name: "Landslides", risk: 7}, {name: "Liquefaction", risk: 5}],
    benefits: [{name: "Copper deposits (world #1)", value: 10}, {name: "Fertile valleys (wine)", value: 8}, {name: "Geothermal potential", value: 7}, {name: "Lithium deposits", value: 9}, {name: "Andean meltwater", value: 7}],
    history: "1960: M9.5 in Chile — largest earthquake EVER recorded. 2010: M8.8 killed 525. Chile has world-class earthquake engineering.",
    lat: -33.4, lon: -70.6
  },
  "Kathmandu, Nepal": {
    boundary: "Convergent (Indian Plate colliding with Eurasian Plate — Himalayas)",
    population: "5 million in valley",
    hazards: [{name: "Earthquake (M7-9)", risk: 10}, {name: "Landslides", risk: 9}, {name: "Avalanches", risk: 7}, {name: "Flooding (glacial lakes)", risk: 7}, {name: "Building collapse", risk: 9}],
    benefits: [{name: "Hydroelectric potential", value: 8}, {name: "Fertile river valleys", value: 7}, {name: "Tourism (Everest, trekking)", value: 9}, {name: "Mineral deposits", value: 5}, {name: "Cultural heritage", value: 9}],
    history: "2015: M7.8 earthquake killed 9,000 and destroyed 600,000 buildings. The Himalayas are still rising 1cm/year. Major earthquake expected.",
    lat: 27.7, lon: 85.3
  },
  "Mexico City, Mexico": {
    boundary: "Convergent (Cocos Plate subducting under North American Plate)",
    population: "22 million in metro area",
    hazards: [{name: "Earthquake", risk: 9}, {name: "Ground amplification (lake bed)", risk: 10}, {name: "Volcanic eruption (Popocatépetl)", risk: 7}, {name: "Subsidence/sinking", risk: 8}, {name: "Landslides", risk: 5}],
    benefits: [{name: "Volcanic soil fertility", value: 8}, {name: "Mineral deposits (silver #1)", value: 9}, {name: "Geothermal energy", value: 6}, {name: "Natural springs", value: 5}, {name: "Cultural heritage", value: 10}],
    history: "1985: M8.0 killed 10,000+. City built on ancient lake bed amplifies shaking 50x. 2017: M7.1 killed 370. Popocatépetl (30 mi away) erupts regularly.",
    lat: 19.4, lon: -99.1
  }
})

{
  const loc = locationData[selectedLocation];
  const div = d3.create("div");
  
  div.append("h3").style("color", "#e17055").style("font-family", "Space Grotesk")
    .text(`📍 ${selectedLocation}`);
  div.append("p").html(`<strong>Tectonic setting:</strong> ${loc.boundary}`);
  div.append("p").html(`<strong>Population at risk:</strong> ${loc.population}`);
  div.append("div").style("background", "#ffecd2").style("padding", "10px").style("border-radius", "8px")
    .style("border-left", "4px solid #e17055").style("margin-bottom", "15px")
    .html(`<strong>📜 Historical context:</strong> ${loc.history}`);

  return div.node();
}

{
  const loc = locationData[selectedLocation];
  const combined = [
    ...loc.hazards.map(h => ({name: h.name, value: h.risk, type: "⚠️ Hazard Risk"})),
    ...loc.benefits.map(b => ({name: b.name, value: b.value, type: "✅ Benefit Value"}))
  ];
  
  return Plot.plot({
    title: `Risk vs. Benefit: ${selectedLocation}`,
    subtitle: "Compare hazard risks and benefits (scale 1-10)",
    width: 700,
    height: 400,
    marginLeft: 200,
    color: {
      domain: ["⚠️ Hazard Risk", "✅ Benefit Value"],
      range: ["#d63031", "#2ecc71"]
    },
    fy: {label: null},
    x: {label: "Score (1-10)", grid: true, domain: [0, 10]},
    y: {label: null},
    marks: [
      Plot.barX(combined, {
        x: "value",
        y: "name",
        fill: "type",
        fy: "type",
        rx: 8,
        sort: {y: "-x"}
      ,
        tip: true}),
      Plot.text(combined, {
        x: "value",
        y: "name",
        fy: "type",
        text: d => d.value.toString(),
        dx: 12,
        fontSize: 12,
        fontWeight: "bold"
      })
    ]
  });
}

{
  const loc = locationData[selectedLocation];
  const avgRisk = (loc.hazards.reduce((sum, h) => sum + h.risk, 0) / loc.hazards.length).toFixed(1);
  const avgBenefit = (loc.benefits.reduce((sum, b) => sum + b.value, 0) / loc.benefits.length).toFixed(1);
  const ratio = (avgBenefit / avgRisk).toFixed(2);
  const verdict = ratio > 1.1 ? "Benefits may outweigh risks" : ratio < 0.9 ? "Risks may outweigh benefits" : "Risks and benefits are roughly balanced";
  const emoji = ratio > 1.1 ? "🟢" : ratio < 0.9 ? "🔴" : "🟡";
  
  const div = d3.create("div").style("text-align", "center").style("padding", "20px")
    .style("background", "linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%)")
    .style("border-radius", "15px").style("margin", "15px 0");
  
  div.append("h3").style("font-family", "Space Grotesk").style("color", "#d63031")
    .text("📊 Summary Score");
  div.append("p").html(`Average Hazard Risk: <strong>${avgRisk}/10</strong> | Average Benefit Value: <strong>${avgBenefit}/10</strong>`);
  div.append("p").html(`Benefit-to-Risk Ratio: <strong>${ratio}</strong>`);
  div.append("h4").html(`${emoji} ${verdict}`);
  div.append("p").style("font-size", "0.9em").style("color", "#636e72")
    .text("Remember: numbers alone don't tell the whole story. Your argument needs scientific reasoning!");
  
  return div.node();
}

22 ✍️ Your CER Argument

22.1 The Framework

Use the Claim–Evidence–Reasoning framework to build your argument:

22.1.1 📌 CLAIM (1-2 sentences)

Make a clear, debatable statement. Does the hazard risk at your chosen location outweigh the benefits, or do the benefits justify the risk?

Example format: “The benefits of living in [location] [do/do not] outweigh the natural hazard risks because…”

22.1.2 📊 EVIDENCE (3-5 specific pieces)

Use evidence from ALL THREE chapters plus the risk assessment tool:

• From Chapter 1 (Earth’s Interior): What’s happening beneath this location? What tectonic processes cause the hazards?
• From Chapter 2 (Plate Boundaries): What type of boundary? What evidence supports plate motion here?
• From Chapter 3 (Energy & Matter): What energy drives the hazards? What resources does this activity create?
• From the Risk Tool: Specific hazard/benefit scores and historical data

22.1.3 🧠 REASONING (3-5 sentences)

Connect your evidence to your claim using scientific principles:

• How do the tectonic processes at this boundary create both hazards AND resources?
• Why is the benefit-to-risk ratio what it is for this location?
• Consider: Can engineering and preparation change the risk level? (Think Japan vs. Nepal)
• Address the counterargument — what would someone who disagrees say?

23 📋 Performance Task Checklist

23.0.1 ✅ Make sure your argument includes:

Understanding of Earth’s Interior (Chapter 1)

• Identifies what’s happening in Earth’s layers beneath your location
• Connects internal structure to surface hazards
• References seismic evidence or density differentiation

Plate Boundary Knowledge (Chapter 2)

• Correctly identifies the plate boundary type
• Explains what features and hazards this boundary type produces
• Uses evidence for plate motion (not just “plates move”)

Energy & Matter (Chapter 3)

• Explains what energy source drives the hazards (mantle convection, radioactive decay)
• Connects tectonic activity to resources/benefits
• Addresses the risk vs. benefit tradeoff with scientific reasoning

CER Quality

• Clear, debatable claim
• At least 3 specific pieces of evidence from different chapters
• Reasoning that connects evidence to claim using science
• Addresses a counterargument
• Uses data from the interactive risk assessment tool

24 🌍 Revisiting the Anchor Phenomenon

🌋 In 1883, Krakatoa killed 36,000 people and changed global temperatures. Today, Anak Krakatoa (“Child of Krakatoa”) is growing in the same spot. In 2018, its flank collapsed and triggered a tsunami that killed 437 people.

The Indonesian government hasn’t evacuated the surrounding coast — because 274 million people depend on the volcanic soil, mineral deposits, and fisheries that plate tectonics creates.

This is the central tension of living on an active planet. Your job is to think scientifically about how we navigate it.

24.0.1 📝 Final Reflection

Look back at the driving question from the unit opening:

Why do the most dangerous places on Earth keep attracting people?

Write a final response (3-5 sentences) that:

1. Answers this question using what you’ve learned
2. Connects Earth’s interior processes to surface hazards AND resources
3. Explains how scientific understanding can help people live more safely in dangerous places