3. Natural Hazards and Disasters

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CSS GSA — Paper 7, Part-I, Section I, Sub-topic 3: Natural Hazards and Disasters

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1. Core Concepts

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Concept formula: Disaster = Hazard × Vulnerability (when capacity is insufficient)

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In simple words: an earthquake in an empty desert is a hazard; the same earthquake under a poorly built city is a disaster.

1.1 Types of Natural Hazard

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In simple words: the class tells you where the danger comes from: the ground (geophysical), the sky (meteorological), water (hydrological), long climate spells (climatological) or living things (biological).

1.2 Hazards in Pakistan

• Natural: droughts, earthquakes, floods, tsunami, avalanches, landslides, cyclones and storms, glacial lake outbursts
• Human-induced: transport accidents, oil spills, urban fires, internal displacement, industrial accidents
• Why Pakistan is so exposed
  • The Indian plate collides with Eurasia in the north (earthquakes, landslides) and the Arabian plate dives under the Makran coast (earthquakes, tsunami)
  • Monsoon rain, snowmelt and glaciers feed the Indus system (floods, glacial lake outbursts, avalanches)
  • A long Arabian Sea coast brings cyclones, while poverty and weak buildings raise vulnerability

1.3 Other Ways to Classify Disasters

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In simple words: a sudden disaster hits like a punch (an earthquake); a slow one creeps up like a fever (a drought). Many "natural" disasters are partly man-made, because people build in dangerous places with weak buildings.

2. Disaster Management

• Disaster Management: organizing and managing resources and responsibilities to handle all humanitarian aspects of emergencies (preparedness, response and recovery)
• Goals
  • Reduce potential losses
  • Reduce risk through short- and long-term policy
  • Assure prompt assistance
  • Achieve rapid, sustained recovery

2.1 Disaster Management Cycle (4 phases)

• In Pakistan
  • NDMA (National Disaster Management Authority) coordinates at the federal level
  • PDMAs (Provincial Disaster Management Authorities) work at the provincial level

2.2 Disaster Risk Management (DRM)

• Disaster risk management: the process of identifying, assessing and reducing the risk of disasters, and preparing to respond and recover
• Risk idea: risk rises with hazard and vulnerability and falls with capacity
• Steps
  1. Risk identification and assessment (hazard maps, vulnerability surveys)
  2. Risk reduction (prevention and mitigation)
  3. Preparedness (early warning, drills, stockpiles)
  4. Response and recovery (rescue, relief, rebuilding better)

• Sendai Framework 2015–2030: the UN framework for disaster risk reduction, with four priorities (understand risk, strengthen governance, invest in resilience, improve preparedness and 'build back better')
• Pakistan
  • Before 2005, disasters were handled under the West Pakistan National Calamities Act of 1958; the 2005 earthquake exposed the gap
  • National Disaster Management Ordinance: promulgated 3 October 2006 and in force from 17 August 2007, when the NDMA was formed (the deck says 2007)
  • National Disaster Management Act: passed on 11 December 2010 (Act XXIV of 2010)
  • Three tiers: the National Disaster Management Commission and NDMA (national), PDMAs (provincial) and DDMAs (district)
  • The NDMA is the implementing, coordinating and monitoring body; Rescue 1122 gives emergency response; the National Institute of Disaster Management (NIDM) trains staff
  • Climate risk: Germanwatch's Climate Risk Index 2026 ranks Pakistan 15th most affected over 1995–2024 (the deck's 8th place is from the 2018 report); the 2025 index named Pakistan the most affected country of 2022
  • Challenges (the deck's view): weak ownership by stakeholders and low spending on disaster management

2.3 Human Response to Natural Hazards

• Reactive (traditional) response: people act after the event
  • Direct impact: people killed and property damaged (affects individuals or small groups)
  • Indirect impact: mental trauma, taxes and donations (affects the whole population)
• Stages of recovery
  1. Emergency: search and rescue, shelter, opening roads
  2. Restoration: water and power, return home, clearing rubble
  3. Reconstruction I: return to the pre-disaster level
  4. Reconstruction II: improvement ("build back better")
• Warning: very rapid restoration can be counter-productive, because weak buildings may simply be rebuilt
• Better approach: proactive risk reduction (the mitigation and preparedness phases above)

3. Earthquakes

3.1 Basics

• Sudden shaking of Earth's surface from a release of energy in the crust
  • Tectonic plates get stuck, build up pressure, then suddenly release it
• Focus (Hypocenter): the point inside Earth where the quake starts
• Epicenter: the point on the surface directly above the focus (usually where damage is greatest)
• Elastic Rebound Theory
  • Rocks bend under stress until they exceed their strength
  • Rocks rupture, then rebound
  • Energy radiates outward as seismic waves
• Seismograph: instrument that records earthquakes
  • Its record is called a seismogram

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In simple words: the plates of the crust are like two rough blocks pushed together; they stick, pressure builds, and when they finally slip, the stored energy is released as shaking.

3.2 Magnitude vs Intensity

• Richter scale (Charles Richter, 1935) has been largely replaced by the moment magnitude scale (Mw), which measures total energy better, especially for great earthquakes (Valdivia 1960 was only about 8.6 on the old Richter scale but 9.5 Mw)
• Size rule: each whole step is ≈ 10 times more ground shaking and ≈ 32 times more energy, so an M7 releases ≈ 1,000 times the energy of an M5
• Intensity uses the Modified Mercalli scale (I to XII); the 2005 quake reached IX–X at Muzaffarabad
• Exam tip: papers still say "Richter scale", so write "magnitude (Richter or moment magnitude)"

3.3 Seismic Waves

3.4 Classification by Focus Depth

3.5 Where, Why and What

• Distribution
  • ≈ 80% in the circum-Pacific belt ("Ring of Fire")
  • ≈ 15% in the Mediterranean-Asiatic belt
  • ≈ 5% elsewhere
    • USGS now says ≈ 90% of all earthquakes (and ≈ 81% of the largest) strike the Ring of Fire, while the Alpide belt (Mediterranean to Himalaya) has ≈ 5–6% of all (≈ 17% of the largest); 80/15/5 is the usual textbook answer
• Causes
  • Tectonic movement
  • Volcanic activity
  • Crustal dislocation
  • Dam-induced stress
  • Underground nuclear tests
  • Landslides and avalanches, faulting and folding of rock beds, and gas pressure in the interior
• Effects
  • Destructive: building collapse, tsunamis, landslides, fissures
  • Constructive: hot springs, and coastal land that rises or sinks can create fertile shores, bays, inlets and fishing grounds (note: Attabad Lake in Hunza was formed by a landslide in 2010, not by an earthquake, although the deck links the two)

3.6 Largest Earthquakes Ever Recorded (USGS list, updated after 2025)

• New entry: the July 2025 Kamchatka earthquake (M 8.8) is the strongest since 2011 and now ranks among the 10 largest ever recorded
• The Valdivia 1960 record (9.5) still stands as the largest

3.7 Can Earthquakes Be Predicted?

• No: scientists have never predicted a major earthquake with its date, place and size; they give probabilities from hazard maps and seismic gaps
• Possible precursors (still unreliable)
  • Tilting or rising or sinking of the land surface
  • Changes in groundwater level, the magnetic field and the electrical resistance of the ground
  • Seismic dilatancy model (rocks swell with tiny cracks before failing)
  • Seismic gaps: a stretch of an active fault that has not ruptured for a long time
• Early warning: the fast P-waves are detected first, giving seconds of warning before the damaging S-waves and surface waves arrive
• Best defence: building codes, retrofitting weak buildings and drills

3.8 Pakistan's Earthquakes

• Main zones: the north (Hindu Kush, Himalaya, Karakoram: Indian–Eurasian collision), the Quetta–Chaman fault zone (Balochistan) and the Makran coast (subduction)

3.9 Recent Big Earthquakes Elsewhere

3.10 Types of Earthquake and Faults

4. Volcanoes

• A volcano is a rupture in Earth's crust that lets magma, ash and gases escape from below the surface

4.1 Types of Volcano (three main, plus three more)

4.2 Effects

• Death of plants and animals (lava, gases)
• Destruction of property
• Ash/dust causing crop damage and respiratory disease
• Can trigger tsunamis, floods and earthquakes
• Can cause global cooling (e.g. Tambora, 1815), because aerosols/ash block sunlight
• Lahars (volcanic mudflows) and pyroclastic flows (hot ash and gas avalanches) are among the deadliest hazards
• Positive side: very fertile volcanic soil and geothermal energy

4.3 Parts of a Volcano

• Magma chamber (reservoir) deep below; conduit (pipe) carries magma up; vent and crater at the top; lava flow down the slopes; ash cloud above
• Parasitic cone: a small side cone fed by a branch of the conduit; sill: a sheet of magma squeezed between rock layers
• Rule of thumb: the thicker (more viscous) the magma, the more explosive the eruption; from gentlest to most violent: flood basalt, shield, cinder cone, composite, dome, caldera
• VEI (Volcanic Explosivity Index) rates eruptions from 0 to 8 (Tambora 1815 was VEI 7)

4.4 Ring of Fire and Volcano Facts

• Ring of Fire: a horseshoe-shaped belt of ocean trenches and volcanoes around the Pacific, about 40,000 km long
  • ≈ 90% of the world's earthquakes and ≈ 75% of its volcanoes (more than 450)
  • Main trenches: Aleutian, Kurile, Japan, Izu-Bonin, Mariana, Philippine, Java (Sunda), Tonga, Peru–Chile, Middle America
• About 1,500 potentially active volcanoes exist worldwide; about 500 have erupted in historic times and more than 50 erupt each year
• Lava temperature is ≈ 700–1,250 °C (the deck says 700–1,300 °C)

4.5 Hunga Tonga–Hunga Haʻapai (15 January 2022)

• An undersea eruption in Tonga; NASA's analysis of satellite data showed the plume rose about 58 km (36 miles) into the mesosphere, about 1.5 times the height of Pinatubo's plume
• It put a record amount of water vapour (up to 150 teragrams) into the stratosphere, sent a pressure wave around the world, and triggered a tsunami that reached Japan and the Americas
• It had little sulphur dioxide, so it was not expected to cool the climate much

4.6 Classification by Activity and Eruption Style

• Magma is molten rock underground; lava is the same material once it erupts onto the surface

• Styles from gentle to violent: Hawaiian → Strombolian → Vulcanian → Plinian
• Volcanic products: lava; pyroclastic material (ash, small fragments, volcanic bombs); gases (steam, carbon dioxide, sulphur dioxide)

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In simple words: runny lava is like pouring honey and flows calmly; thick, gassy magma is like a shaken soda bottle and blasts out.

5. Tsunamis

• Arise from the sudden displacement of water masses
• ≈ 80–86% are caused by undersea earthquakes ("seaquakes"); NOAA's split is ≈ 80% earthquakes, ≈ 6% volcanoes, ≈ 5% landslides (plus ≈ 7% earthquake-triggered landslides)
• Conditions for a seaquake-triggered tsunami
  • Earthquake of 7.0 Richter or more
  • Seabed lifted or lowered
  • Epicenter near Earth's surface
• Warning systems
  • Triggered when an undersea quake above magnitude 6.5 is detected
  • Buoys and tide gauges verify whether a tsunami is actually present
• Primary effects: deaths/injuries, infrastructure destruction, coastal erosion, ecosystem damage (coral reefs, mangroves)
• Secondary effects
  • Disease outbreaks (malaria, cholera, typhoid, hepatitis)
  • Psychological trauma
  • Displacement and refugee camps
  • Food shortages
  • GDP decline

5.1 Tsunami Facts, Records and Warning

• Speed: up to ≈ 800 km/h (500 mph) in the deep ocean, where the wave is low and very long (wavelength 100–200 km); near the coast it slows to 30–50 km/h but grows tall (up to 30 m or more)
• Warning
  • USGS: earthquakes below magnitude 6.5 are very unlikely to cause a tsunami, and those of 6.5–7.5 rarely cause a destructive one, which is why the usual rule says 7.0 or more
  • Natural signs: long or strong shaking, the sea suddenly pulling back, a loud ocean roar
  • DART buoys (Deep-ocean Assessment and Reporting of Tsunamis): a seabed pressure recorder sends signals by sound to a surface buoy, which relays them by satellite; tide gauges confirm

• Tsunami: a series of very long sea waves caused by a sudden displacement of a large volume of water (Japanese: tsu = harbour, nami = wave)

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In simple words: a tsunami is not one big wave but a train of waves, and the sea may pull far back just before it hits; it has nothing to do with tides.

• Pakistan: the 1945 Makran earthquake (M 8.1) produced a tsunami with waves of 12–15 m at Pasni and killed about 4,000; the Makran coast, and Karachi with it, remain at risk

6. Floods

• Impacts
  • Economic: destroyed roads, crops and homes
  • Environmental: water contamination, ecosystem imbalance
  • Health problems
  • Displacement of people

6.1 Major Floods in Pakistan (latest figures)

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Exam tip: for 2022 floods, remember "one-third of Pakistan under water, 33 million affected". Pakistan contributes less than 1% of global emissions yet is among the most flood-hit countries, which links to climate change.

6.2 Flood Types, Causes and Effects

• Factors that encourage flooding: steep-sided channels and lack of vegetation
• Causes: heavy rain, river overflow, breaking of dams or embankments, rapid snow and ice melt, global warming, and silt (sedimentation) filling river beds and reservoirs
• Effects
  • Primary: physical damage, deaths, loss of resources
  • Secondary: soil erosion, land degradation, health effects, water pollution
  • Tertiary (long term): economic hardship, rebuilding costs, food shortages, poverty
• Management
  • Structural: dams, embankments, spillways, flood channels
  • Non-structural: flood forecasting and warning (Pakistan Meteorological Department, Federal Flood Commission), flood-plain zoning, planting trees, public awareness

6.3 Glacial Lake Outburst Floods (GLOFs)

• GLOF: a lake formed by melting glaciers sits behind a natural dam of ice, rock or loose debris; when the dam suddenly fails, millions of cubic metres of water and debris rush out within hours
• Pakistan: melting Hindu Kush, Karakoram and Himalayan glaciers have created 3,044 glacial lakes in Gilgit-Baltistan and Khyber Pakhtunkhwa; 33 are judged hazardous and over 7 million people are threatened (UNDP)
• Response: the GLOF-II project (UNDP, Ministry of Climate Change and the Green Climate Fund) builds early-warning systems and small engineering works such as controlled drainage and mini dams
• Climate link: warmer temperatures melt glaciers faster, so lakes grow and GLOF risk rises

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In simple words: a GLOF is a natural dam made of ice or rubble holding back a mountain lake; if it bursts, the lake empties down the valley in hours.

6.4 Landslides

• Landslide: the downhill movement of rock, soil and debris on a slope (a mass movement; also in the hydrological class of hazards)
• Causes: heavy rain and saturated soil, earthquakes, steep slopes, deforestation, road and building cuts, river undercutting
• Pakistan: the northern mountains (Gilgit-Baltistan, Khyber Pakhtunkhwa, Azad Kashmir, the Murree hills) and the Karakoram Highway; monsoon landslides often come with floods
• Types of landslide (a landslide is a mass movement: rock, soil or debris moving downhill under gravity)

• Case: Attabad, Hunza (4 January 2010)
  • A landslide killed 20 people and blocked the Hunza River for five months
  • It created Attabad Lake (≈ 21 km long, over 100 m deep), flooded about 19 km of the Karakoram Highway and affected up to 25,000 people
  • It was a landslide, not an earthquake effect
• Prevention: planting trees, slope stabilisation and retaining walls, drainage, no building on unstable slopes, hazard maps and early warning

7. Avalanches

• Avalanche: rapid flow of snow down a slope

7.1 Four Main Types

• Causes
  • Weather (wind, temperature, snowfall)
  • Terrain (slope angle and shape, vegetation)
  • Snowpack stability
  • Human factors (winter sports, deforestation reducing snow stability)
  • The 24 hours after a heavy snowstorm are the most critical
• Effects: loss of life and property, traffic blockage, floods, damage to flora/fauna/tourism
• Avalanche hazard triangle: an avalanche needs three things together: avalanche terrain (a steep slope), unstable snow and people or property in the path
• Slope angle: slab avalanches mostly release on slopes of about 25–45°
• Management: avalanche forecasts, controlled release, snow fences and avalanche sheds on roads, planting trees, avoiding steep slopes after storms; rescue kit is a beacon, probe and shovel

8. Cyclones and Tornadoes

• Cyclone: a large rotating air mass around a low-pressure center
  • Counterclockwise in the Northern Hemisphere
  • Clockwise in the Southern Hemisphere
• Types of cyclone
  • Tropical cyclone (hurricane/typhoon): forms over warm tropical oceans
  • Polar cyclone: occurs in polar regions (Greenland, Siberia, Antarctica), usually stronger in winter
  • Mesocyclone: rotating part of a thunderstorm; can develop into a tornado
• Impacts
  • Wind damage (Category 5 = winds of 157 mph / 252 km/h or more)
  • Flooding from storm surge and rainfall
  • Coastal erosion
• Tornado
  • Violently rotating funnel of air / thunderstorm cloud that extends to the ground
  • Typically mid-afternoon to early evening
  • Moves southwest → northeast
  • Covers ≈ 300–400 yards

8.1 Middle Latitude Cyclone vs Tornado (quick comparison)

• Middle latitude cyclone: huge (1,000 km or more), forms along the polar front, lasts days, brings widespread rain or snow; Pakistan's winter western disturbances are of this type
• Tornado: small (tens to hundreds of metres), forms from a supercell thunderstorm, lasts minutes, with the strongest winds
• The full comparison table is in the past-paper section below

8.2 Names and Categories of Tropical Cyclones

• Same storm, different names: hurricane (Atlantic and north-east Pacific), typhoon (north-west Pacific), cyclone (Indian Ocean and South Pacific), "willy-willies" (an old Australian name)
• Formation: warm sea surface (about 26.5 °C or more), warm moist air rising, low pressure, Coriolis effect and low wind shear

• Category 3 and above are called major hurricanes; the scale rates wind only, not storm surge or rain

8.3 Cyclones in the Arabian Sea and Pakistan

• Naming: since 2004 the WMO/ESCAP Panel on Tropical Cyclones has assigned names; 13 countries (including Pakistan) supply them, RSMC New Delhi names storms in the Bay of Bengal and Arabian Sea, and a name is never reused
• Recent examples
  • Biparjoy (June 2023, name from Bangladesh): lasted about 13 days and made landfall on the Gujarat–Sindh coast on 16 June
  • Asna (2024): a name supplied by Pakistan
  • Shakhti (October 2025, name from Sri Lanka): formed in the north-east Arabian Sea, at one point about 330 km from Karachi
• Trend: a warming Arabian Sea is producing stronger, fast-intensifying cyclones (Tauktae 2021, Biparjoy 2023)

8.4 Tornado Scale: Enhanced Fujita (EF)

• The Fujita scale (1971) was replaced by the Enhanced Fujita scale in the US on 1 February 2007; it rates tornadoes by the damage they cause, and wind speeds are only estimates
• The deck's old F-scale table (F5 = 261–318 mph) is outdated

8.5 Types of Cyclone and Tornado at a Glance

• In the Arabian Sea and Bay of Bengal the India Meteorological Department uses its own scale: depression (31–49 km/h), deep depression (50–61), cyclonic storm (62–88), severe cyclonic storm (89–117), very severe (118–166), extremely severe (167–221) and super cyclonic storm (222 km/h or more)

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In simple words: a cyclone is a giant spinning storm around low pressure. Tropical cyclones are powered by warm sea water, mid-latitude cyclones by the clash of warm and cold air, and tornadoes are small but far more violent.

9. Drought

• Drought: a deficiency of rainfall over an extended period relative to the regional multi-year average

9.1 Types of Drought

• Usual order: meteorological (no rain) → agricultural (crops suffer) → hydrological (rivers, dams and wells drop) → socioeconomic (people feel the shortage)

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In simple words: a drought is not just "no rain"; it is a shortage of water compared with what is normal, and it spreads from the sky to the fields to the rivers to people's lives.

• Causes: lack of rainfall, dry seasons, deforestation, global warming
• Effects: crop failure, famine, desertification, malnutrition, mass migration/refugee crises, wildfires, economic loss
• Management strategies
  • Dams/reservoirs
  • Desalination
  • Drought monitoring
  • Crop rotation
  • Cloud seeding
  • Water-use restrictions
  • Rainwater harvesting
  • Water recycling
  • River redirection
• Monitoring from space: NASA's GRACE-FO and SMAP satellites track groundwater and soil moisture, which helps spot drought early

9.2 Wildfire

• Wildfire: an uncontrolled fire in forest, grassland or scrub
• Types of wildfire (by where the fire burns)

• Causes: lightning, drought and heat; human causes such as campfires, cigarettes, arson, crop burning and power-line sparks
• Spread depends on fuel, weather (wind, dryness) and slope (fires run faster uphill)
• Prevention: firebreaks, controlled burns, early detection, public awareness, better forest management
• Fire triangle (the deck's elements of combustion): oxygen + heat + fuel
• Who starts them: the deck says about 90% are human-caused; in the US the National Park Service puts it at about 85%, with lightning and volcanic eruptions behind the rest
• NASA tool: the Fire Information for Resource Management System (FIRMS) shows active fires from the MODIS and VIIRS satellite sensors within about 3 hours of a satellite pass

9.3 Urban Fire

• Urban fire: fire in buildings, factories, markets and settlements of a city
• Fire triangle: heat + fuel + oxygen; remove one and the fire goes out
• Causes: electrical short circuits, gas leaks, cooking accidents, cigarettes, chemicals, arson
• Why cities are at risk: crowded buildings, flammable materials, narrow lanes that block fire engines, poor wiring, few exits
• Pakistan example: the Baldia Town factory fire, Karachi (2012) killed about 260 people, mostly because of locked exits and no fire safety
• Prevention and control: building and fire codes, working alarms and sprinklers, extinguishers, clear escape routes, safe wiring and gas fittings, fire drills, rescue services (Rescue 1122 and fire brigades)
• Classes of fire (letters differ slightly by country; this is the UK and Europe system)

10. Named Case Studies (Past Paper Favorites — Learn These Cold)

10.1 2005 Kashmir / Muzaffarabad Earthquake

• Date: 8 October 2005, at 08:50 am Pakistan time (03:50 UTC); the deck says 08:25
• Magnitude: 7.6 (Mw)
• Depth: shallow (≈ 10–26 km depending on the agency)
• Aftershocks: 1,778 recorded by the end of 2005; the strongest was M 6.4 on the same day (the deck mentions 20 powerful ones)
• Epicenter: near Muzaffarabad, Azad Kashmir (≈ 19 km NE of the city, about 100 km north-north-east of Islamabad; the deck says 80 km)
• Cause: thrust faulting, where the Indian plate pushes under the Eurasian plate (Himalayan collision zone)
• Impact
  • Killed roughly 87,000+ people in Pakistan
  • Injured 200,000+
  • Left ≈ 4 million homeless
• Significance: the deadliest earthquake in the Indian subcontinent's recorded history

10.2 7 April 2012 Gayari Sector Avalanche

• Location: Pakistan Army base (6th Northern Light Infantry HQ) near the Siachen Glacier, Gilgit-Baltistan, at ≈ 4,500 m altitude
• Impact
  • Buried the camp under 70–100 feet of snow, ice and rock
  • Killed 140 people (129 soldiers + 11 civilians)
• Significance: an example of a slab/ice-rock avalanche triggered by unstable high-altitude snowpack, a classic "avalanche type and cause" exam example

10.3 22 May 1960 Chile (Valdivia) Earthquake

• Magnitude 9.5: the largest earthquake ever recorded
• Struck southern Chile near Valdivia
• Caused by subduction of the Nazca Plate beneath the South American Plate
• Generated a major tsunami that crossed the Pacific and caused damage and deaths as far as Hawaii and Japan
• Killed about 1,655 people and left about 2 million homeless (USGS)

10.4 1815 Mount Tambora Eruption (Indonesia)

• The largest volcanic eruption in recorded history (VEI 7), on Sumbawa Island
• Killed an estimated 70,000–100,000+ people (direct blast, tsunami, and later famine/disease)
• Ash and aerosols caused global cooling
• 1816 became known as the "Year Without a Summer" (crop failures across Europe and North America)

📈 Disaster risk: how hazard becomes disaster

• Hazard: Potentially dangerous event (e.g., earthquake); exposure: people and assets in harm's way; vulnerability: their susceptibility to loss; capacity: resources and preparedness to cope.
• Conceptual relationship: Disaster risk increases with hazard × exposure × vulnerability, and can fall as coping/adaptive capacity improves; this is a conceptual model, not a universal numerical equation.
• Example: The same earthquake may kill more people where poorly built buildings, high exposure and weak response capacity coincide.
• Prevention vs mitigation vs preparedness: Avoid building in unsafe zones → strengthen buildings and embankments → drills, evacuation routes and emergency kits → emergency response → recovery and reconstruction.
• Pakistan examples: Flash floods in steep catchments need early warnings; urban flooding needs drainage and land-use planning; seismic zones need enforced building codes.

🌊 Earthquake and tsunami mechanisms — past-paper connections

• Magnitude: Measures earthquake size/source energy (modern reports generally use moment magnitude Mw); an increase of 1 magnitude ≈ 10 times wave amplitude and ~31.6 times energy. Intensity measures shaking and damage at a particular location.
• Focus (hypocentre): Rupture origin within Earth; epicentre: ground-surface point vertically above it; not interchangeable.
• Seismic waves: P = compressional, fastest, pass through solids and liquids; S = shear, cannot pass through liquids; surface waves = travel along surface and often produce severe shaking.
• Tsunami formation: Undersea seafloor displacement (commonly a large shallow thrust earthquake) pushes a water column → long waves spread across ocean → speed drops and height rises in shallow water.
• Key distinction: A tsunami is not a tidal wave; astronomical tides arise predominantly from lunar and solar gravitational forces.
• Cyclone contrast: Tropical cyclones gain energy from warm ocean moisture/latent heat, and their damaging storm surge can be deadlier than wind; mid-latitude cyclones are typically driven by temperature contrasts along fronts.
• Avalanche classification: Distinguish loose-snow vs slab release and dry vs wet snow; slabs can fracture and release large cohesive snow masses.

11. MCQ Traps

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• Magnitude (Richter) = one value per earthquake, energy released; Intensity (Mercalli) = varies by location, damage felt
• Tsunamis are caused by seismic/tectonic activity, not wind (unlike ordinary ocean waves)
• S-waves travel through solids only; P-waves travel through solids, liquids and gases
• Disaster-management-cycle order: Mitigation → Preparedness → Response → Recovery
• The largest earthquake is still Valdivia 1960 (9.5); the 2025 Kamchatka quake (8.8) is only tied 6th
• Shallow-focus quakes are the most destructive; deep-focus ones are felt less at the surface
• Richter is the old name; seismologists now use moment magnitude (Mw); Mercalli is intensity (I to XII)
• Attabad Lake (Hunza) came from the 2010 landslide, not an earthquake
• Tornado ratings now use the Enhanced Fujita (EF) scale (since 2007), not the old Fujita scale
• Ring of Fire: about 90% of earthquakes and about 75% of volcanoes
• NDM Act was passed in 2010; the NDMA was formed in 2007 after the 2006 ordinance
• 2022 floods: damage plus loss is about US$30 billion, not US$40 billion; 2025 monsoon killed 1,037 people
• Glacial lakes: 3,044 in Gilgit-Baltistan and Khyber Pakhtunkhwa, of which 33 are hazardous
• Magma is underground; lava is on the surface
• Reverse (thrust) faults come from convergent boundaries (Himalaya, 2005 Kashmir); strike-slip faults come from transform boundaries (Chaman Fault)
• A tropical storm (63–118 km/h) is not yet a hurricane (119 km/h or more)
• A tsunami is a train of waves, not a single wave, and is not a tide
• Class B fires (flammable liquids) must never be fought with water

12. Self-Test Questions

1. Distinguish between hazard, vulnerability, and capacity in the context of disaster risk.
2. List and briefly describe the four phases of the Disaster Management Cycle.
3. Differentiate between the Richter scale and the Mercalli scale.
4. Explain the three conditions required for a seaquake to generate a tsunami.
5. List the four types of drought and one cause of drought overall.
6. What was the intensity of the 2005 Pakistan earthquake, and where was its locus?
7. On 7 April 2012, an avalanche hit a Pakistan military base in the Gayari sector, trapping 140 soldiers and civilians under deep snow. What is an avalanche, and describe its four types with focus on the most dangerous type.
8. The world's largest earthquake was assigned a magnitude of 9.5 by the USGS on 22 May 1960 in southern Chile (Valdivia). What do you know about this earthquake? Also explain shallow-focus and deep-focus earthquakes.
9. The largest recorded volcanic eruption occurred in Indonesia in 1815, leading to calamity, starvation, and mass deaths. What are volcanic eruptions, and what are their three main types?
10. Classify natural hazards into five types, with an example of each.
11. Why has the moment magnitude scale replaced the Richter scale?
12. What is a glacial lake outburst flood, and why is Pakistan at risk?
13. Describe the National Disaster Management Act 2010 and the three tiers of disaster management in Pakistan.
14. Classify disasters by cause and by speed of onset, with examples.
15. Classify earthquakes by cause and name the three types of fault with an example of each.
16. Differentiate between active, dormant and extinct volcanoes, and between magma and lava.
17. Differentiate between a tsunami, a tide and a wind wave.
18. Name the stages of a tropical cyclone and the types of tornado.

13. Past-Paper MCQs (FPSC)

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Taken from the FPSC papers you shared (2015–2025). FPSC does not publish MCQ keys, so the answers are worked out by me; double-check the one marked with a note.

1. (CSS 2025, Q1.2) Most major Tsunamis are produced by earthquakes with hypocenters less than: (A) 30 km (B) 40 km (C) 50 km (D) None of these
2. (CSS 2024, Q1.16) Earthquake is measured by the instrument: (A) Wave guide (B) Barometer (C) Seismograph (D) Hydrometer
3. (CSS 2024, Q1.17) A cyclone is formed: (A) When the warm air rises upward over the ocean (B) When moist air rises upward over the ocean (C) When moist air pressed downward over the ocean (D) When warm, moist air rises upward over the ocean

• ✅ Answer key
  1. (D) None of these. Note: USGS says shallow-focus earthquakes (depth under 70 km) along subduction zones cause most destructive tsunamis, and 70 km is not among the options; there is no official key, so treat this as my best reading
  2. (C) Seismograph
  3. (D) When warm, moist air rises upward over the ocean (warm, moist air rising creates the low-pressure centre)

14. Past-Paper Long Questions with Answers (FPSC)

✅

Every question below appeared in the FPSC papers you shared; the year and question number are in each title. Answers are model outlines written by me, ready to expand.

• CSS 2016 Q7(a): What is a tsunami? How are tsunamis generated and what are their characteristics? (5)

  • Tsunami: a series of very long sea waves caused by the sudden displacement of a large mass of water (Japanese: tsu = harbour, nami = wave)
  • How generated
    • Undersea earthquakes (≈ 80–86%): the seabed is suddenly lifted or dropped; needs magnitude 7.0 or more, a shallow focus and vertical movement of the seabed
    • Undersea landslides
    • Volcanic eruptions (e.g. Krakatoa, 1883)
    • Meteorite/asteroid impact
  • Characteristics
    • Very long wavelength (can exceed 100 km) and a long time between crests
    • In deep ocean: speed ≈ 800 km/h, but height only about a metre or less (often unnoticed by ships)
    • Near the coast: slows down, wave grows tall (shoaling) and can run far inland
    • Comes as a wave train: the first wave is often not the largest
    • Sea may retreat suddenly before the wave arrives (a natural warning sign)
    • Can cross entire oceans

• CSS 2018 Q4(D): Describe different causes of tsunami. Is there any difference between a tsunami and a tidal wave? Name the worst tsunami ever recorded. (5)

  • Causes: undersea earthquakes (the main cause), submarine landslides, volcanic eruptions, meteorite impact, glacier or rock falls into water

  • Tsunami vs tidal wave

    Feature	Tsunami	Tidal wave
    Cause	Seabed displacement (earthquake, landslide, eruption)	Gravity of the Moon and Sun (tides)
    Predictable?	No; sudden	Yes; regular daily cycle
    Right name?	Correct scientific term	‘Tidal wave’ is a misleading old name for a tsunami

  • Worst tsunami ever recorded

    • Deadliest: the 2004 Indian Ocean tsunami (26 December 2004), caused by the M 9.1–9.3 Sumatra-Andaman earthquake; about 230,000 deaths in 14 countries
    • Tallest wave: Lituya Bay, Alaska (1958), run-up about 524 m (1,720 ft), but only 5 deaths
    • Costliest: Tohoku, Japan (2011), estimated US$309 billion

• CSS 2016 Q7(b): What is an earthquake? Discuss the Richter scale in this context. What was the intensity of the earthquake in Pakistan dated 26 October 2015 and where was the locus? (5)

  • Earthquake: sudden shaking of the ground from a release of energy in the crust (focus below, epicenter above)
  • Richter scale
    • Measures magnitude (energy released), one value per earthquake
    • Logarithmic: each whole number is about 10 times larger in shaking and about 32 times more energy
    • Intensity (damage felt) is a different measure, on the Mercalli scale
    • Today seismologists use the moment magnitude scale (Mw), which has largely replaced Richter for large quakes
  • 26 October 2015 earthquake
    • Magnitude 7.5 (Mw) per USGS; the Pakistan Meteorological Department reported 8.1
    • Locus (epicenter): the Hindu Kush region of north-eastern Afghanistan (Badakhshan, near Jurm), felt strongly in Pakistan
    • Depth: very deep, ≈ 200–230 km depending on the agency (an intermediate-focus quake, so shaking was widespread but less intense than a shallow one)
    • Toll: about 399 deaths across Afghanistan, Pakistan and India, with Khyber Pakhtunkhwa worst hit in Pakistan
    • Compare: the 2005 Kashmir quake was M 7.6 and shallow, which is why it killed far more

• CSS 2015 Q6(a): Write a short note on Seismography. (5)

  • Seismography: the science of recording and measuring earthquake waves
  • Seismograph: the instrument; a heavy mass hung on a spring or pendulum stays still while the ground moves, and the relative motion is recorded
  • Seismogram: the recorded trace, showing P-waves first, then S-waves, then surface waves
  • Uses
    • Locate the epicenter: the gap between P- and S-wave arrival times gives distance, and three stations together pinpoint it
    • Calculate magnitude
    • Study Earth's interior (S-waves cannot pass through the liquid outer core)
    • Detect underground nuclear tests and support early warning
  • Modern: digital, networked broadband seismometers

• CSS 2024 Q5(c): What are the types of earthquake waves? Discuss them. (5)

  Group	Wave	Features
  Body waves	P-waves (Primary)	Fastest; compressional (push-pull); travel through solids, liquids and gases; arrive first
  Body waves	S-waves (Secondary)	Slower; shear (side-to-side); solids only
  Surface waves	Love waves	Horizontal ground shaking; lower frequency; arrive last
  Surface waves	Rayleigh waves	Rolling motion like ocean waves; cause most destruction

• CSS 2020 Q2(c): The world's largest earthquake was assigned a magnitude of 9.5 by the USGS on 22 May 1960 in southern Chile (Valdivia). What do you know about earthquakes? Also explain shallow-focus and deep-focus earthquakes. (5)

  • Earthquake: sudden release of energy in the crust as plates stick, build stress and then rupture (elastic rebound); energy spreads as seismic waves

  • Valdivia 1960: M 9.5, the largest ever recorded; caused by the Nazca Plate subducting under the South American Plate; killed about 1,655 and left about 2 million homeless; its tsunami crossed the Pacific to Hawaii and Japan

  • Shallow vs deep focus

    Feature	Shallow-focus	Deep-focus
    Depth	0–70 km	300–700 km (intermediate: 70–300 km)
    Frequency	Most common	Rare; mainly in subduction zones
    Surface damage	Most destructive (short path to the surface)	Felt less intensely, as energy fades over the long path
    Example	2005 Kashmir	Hindu Kush quakes are deep-ish (≈ 200 km)

• CSS 2020 Q2(a): On 7 April 2012 an avalanche hit a Pakistan military base in Gayari sector trapping 140 soldiers and civilians under deep snow. What is an avalanche? Describe its four types with focus on the most dangerous type. (5)

  • Avalanche: a rapid flow of snow down a slope
  • Four types
    • Loose-snow (sluff): starts at a point and fans out; usually small
    • Slab: a cohesive block breaks off a weak layer and slides as one mass; most dangerous, causing most avalanche deaths
    • Powder: fast, fine airborne snow with a pressure blast
    • Wet-snow: slower but very heavy and dense
  • Gayari (2012): near Siachen, ≈ 4,500 m; 140 killed (129 soldiers + 11 civilians); buried under 70–100 ft of snow, ice and rock
  • Causes: weather, steep terrain, unstable snowpack, human activity; the first 24 hours after heavy snowfall are most critical

• CSS 2022 Q2(a): What do you know about volcanoes? Discuss the causes and effects of volcanic eruptions. (5)

  • Volcano: a rupture in the crust through which magma, ash and gases escape
  • Causes
    • Plate boundaries: subduction zones (melting of the descending plate) and divergent boundaries (magma rises into gaps)
    • Hotspots (e.g. Hawaii)
    • Magma rising because it is lighter than surrounding rock, with eruptions driven by dissolved gas pressure
  • Types: shield (gentle, effusive), composite/stratovolcano (explosive), cinder cone (small, moderately explosive)
  • Effects
    • Deaths and loss of plants and animals; property destruction
    • Ash damaging crops and causing respiratory disease
    • Tsunamis, floods and earthquakes
    • Global cooling (Tambora 1815 and the ‘Year Without a Summer’, 1816)
    • Positive effect: fertile volcanic soil

• CSS 2019 Q3(c), 2025 Q2(c): What are hurricanes? How are they formed and what level of damage can they produce? What is the most dangerous part and how do cyclones affect humans? (5)

  • Hurricane: a very large rotating storm around a low-pressure centre, with winds of at least 74 mph (the same storm is a typhoon in the NW Pacific and a cyclone in the Indian Ocean)
  • Formation
    • Warm ocean water (about 26.5 °C or more)
    • Warm, moist air rises, pressure drops, more air rushes in and spirals (Coriolis effect, away from the equator)
    • Low wind shear; the storm weakens over land or cold water
  • Structure: calm eye, strongest eyewall, outer rainbands
  • Damage levels (Saffir–Simpson scale): Category 1 = 74–95 mph; Category 2 = 96–110; Category 3 = 111–129; Category 4 = 130–156; Category 5 = over 156 mph
  • Most dangerous part: the storm surge (wall of sea water pushed ashore), which causes most deaths; the eyewall has the strongest winds
  • Effects on humans: deaths and injuries, flooding, destroyed homes, displacement, disease, crop and livelihood loss, power and transport failure, economic damage

• CSS 2020 Q5(b), 2024 Q2(c): Differentiate between Middle Latitude Cyclones and Tornadoes. (5)

  Feature	Middle Latitude Cyclone	Tornado
  Size	Huge: 1,000 km or more across	Small: tens to hundreds of metres wide
  Origin	Along the polar front, where warm and cold air masses meet	From severe thunderstorms (supercells)
  Duration	Several days	Minutes to an hour
  Wind speed	Moderate to strong	Extreme, up to about 480 km/h
  Weather	Widespread cloud, rain or snow, with warm and cold fronts	Funnel cloud with a narrow path of destruction
  Movement	Steered west → east by the westerlies	Usually southwest → northeast

  • Pakistan link: winter ‘western disturbances’ are middle-latitude cyclones

• CSS 2022 Q2(c): What is a tornado? How is it formed and what are the effects of tornadoes? (5)

  • Tornado: a violently rotating column of air that extends from a thunderstorm cloud to the ground
  • Formation
    • Warm, moist air near the ground meets cold, dry air above, making the air unstable
    • Wind shear (winds changing speed/direction with height) creates a horizontal spinning tube
    • A strong updraft tilts it upright, forming a rotating mesocyclone
    • The funnel extends down and touches the ground
  • Features: usually mid-afternoon to early evening; travels southwest → northeast; narrow path of about 300–400 yards
  • Effects: destroyed buildings and vehicles, flying debris causing injuries and deaths, power-line damage, crop and livestock loss
  • Scale: measured by damage on the (Enhanced) Fujita scale

• CSS 2023 Q2(d): What is wildfire? Explain its types, causes, spread and preventions. (5)

  • Wildfire: an uncontrolled fire burning in forest, grassland or scrub
  • Types
    • Ground fire: burns underground organic matter (peat, roots), smoulders for long
    • Surface fire: burns litter, grass and low shrubs
    • Crown fire: spreads through treetops; fastest and most destructive
  • Causes
    • Natural: lightning, volcanic activity, prolonged drought and heat
    • Human: unattended campfires, cigarettes, arson, burning of crop residue, sparks from power lines and machinery
  • Spread: depends on fuel (dry vegetation), weather (wind, heat, low humidity) and terrain (fire runs faster uphill); embers can start new fires far ahead
  • Prevention and control
    • Firebreaks and clearing dry undergrowth; controlled burning
    • Public awareness and bans on open fires in dry season
    • Early detection (watchtowers, satellites) and fast fire-fighting
    • Better land and forest management
  • Effects: loss of forests, wildlife and homes, air pollution and smoke, soil erosion, carbon emissions

15. Extra Practice MCQs (exam-style, not official)

ℹ️

These are exam-style practice questions written by me, not copied from FPSC papers. The official past-paper MCQs are in the section above.

1. The Richter scale measures: (a) Intensity (b) Magnitude (c) Depth (d) Duration
2. The fastest seismic waves are: (a) S-waves (b) Love waves (c) P-waves (d) Rayleigh waves
3. Which seismic waves cannot travel through liquids? (a) P-waves (b) S-waves (c) Both (d) Neither
4. The largest earthquake ever recorded occurred in: (a) Alaska 1964 (b) Valdivia, Chile 1960 (c) Sumatra 2004 (d) Japan 2011
5. The 2005 Kashmir earthquake struck on: (a) 8 October 2005, magnitude 7.6 (b) 26 October 2005, magnitude 6.0 (c) 8 October 2005, magnitude 9.0 (d) 8 October 2008, magnitude 7.6
6. The largest volcanic eruption in recorded history was: (a) Krakatoa 1883 (b) Vesuvius 79 AD (c) Tambora 1815 (d) Mount St. Helens 1980
7. The most dangerous type of avalanche is the: (a) Loose-snow (b) Slab (c) Powder (d) Wet-snow
8. About what share of earthquakes occur in the circum-Pacific belt? (a) 15% (b) 50% (c) 80% (d) 5%
9. Shallow-focus earthquakes have a depth of: (a) 0–70 km (b) 70–300 km (c) 300–700 km (d) Over 700 km
10. 1816 is known as the: (a) Year of Floods (b) Year Without a Summer (c) Year of Famine (d) Ice Year
11. The first phase of the disaster management cycle is: (a) Response (b) Recovery (c) Mitigation (d) Preparedness
12. A tsunami from an undersea earthquake typically requires a magnitude of at least: (a) 5.0 (b) 6.0 (c) 7.0 (d) 9.0
13. The scale that has largely replaced the Richter scale is the: (a) Mercalli (b) Moment magnitude (c) Beaufort (d) Fujita
14. Which hazard class includes drought, wildfire and glacial lake outbursts? (a) Geophysical (b) Hydrological (c) Climatological (d) Biological
15. Pakistan's National Disaster Management Act was passed in: (a) 2005 (b) 2007 (c) 2010 (d) 2022
16. Attabad Lake in Hunza was formed by a: (a) earthquake (b) landslide (c) glacier surge (d) volcanic eruption
17. Of the 3,044 glacial lakes in Gilgit-Baltistan and Khyber Pakhtunkhwa, how many are judged hazardous? (a) 3 (b) 33 (c) 303 (d) 3,000
18. The tornado rating scale used today in the US is the: (a) Fujita (b) Saffir–Simpson (c) Enhanced Fujita (d) Beaufort
19. A Category 5 hurricane has sustained winds of at least: (a) 74 mph (b) 111 mph (c) 130 mph (d) 157 mph
20. A tsunami's speed in the deep ocean is about: (a) 8 km/h (b) 80 km/h (c) 800 km/h (d) 8,000 km/h
21. Pakistan's deadliest earthquake (about 87,000 deaths) was in: (a) Quetta 1935 (b) Makran 1945 (c) Kashmir 2005 (d) Awaran 2013
22. About what share of the world's volcanoes lie in the Ring of Fire? (a) 25% (b) 50% (c) 75% (d) 100%
23. A fault where one block is pushed up over another is a: (a) normal fault (b) reverse (thrust) fault (c) strike-slip fault (d) transform fault
24. Molten rock below the surface is called: (a) lava (b) magma (c) ash (d) lahar
25. A tropical storm has sustained winds of: (a) under 62 km/h (b) 63–118 km/h (c) 119–153 km/h (d) 252 km/h or more
26. Which class of fire involves flammable liquids such as petrol? (a) A (b) B (c) C (d) D
27. A landslide that moves like a thick liquid is a: (a) fall (b) topple (c) flow (d) creep

• ✅ Answer key
  1. (b) Magnitude (Mercalli = intensity)
  2. (c) P-waves
  3. (b) S-waves (solids only)
  4. (b) Valdivia, Chile 1960 (M 9.5)
  5. (a) 8 October 2005, M 7.6
  6. (c) Tambora 1815 (VEI 7)
  7. (b) Slab avalanche
  8. (c) ≈ 80% (Ring of Fire)
  9. (a) 0–70 km
  10. (b) Year Without a Summer (after Tambora)
  11. (c) Mitigation
  12. (c) 7.0 Richter or more
  13. (b) Moment magnitude (Mw)
  14. (c) Climatological
  15. (c) 2010 (11 December 2010)
  16. (b) Landslide (4 January 2010)
  17. (b) 33
  18. (c) Enhanced Fujita (since 1 February 2007)
  19. (d) 157 mph (252 km/h) or more
  20. (c) About 800 km/h
  21. (c) Kashmir 2005 (Quetta 1935 killed 30,000–60,000)
  22. (c) About 75%
  23. (b) Reverse (thrust) fault, found at convergent boundaries
  24. (b) Magma (it is called lava once it erupts)
  25. (b) 63–118 km/h (a depression is lower; a hurricane is 119 km/h or more)
  26. (b) Class B (use foam, CO₂ or dry powder, never water)
  27. (c) Flow (debris flow or mudflow)

16. Extra Practice Long Questions (20 Marks)

ℹ️

Extra practice built from the syllabus. ✅ = a version of this question has appeared in an FPSC paper (exact wording and years are in the section above).

1. ✅ What is a tsunami? Explain its causes and the conditions under which an earthquake generates one (reported: CSS 2018)
2. ✅ What is an avalanche? Describe its four types, focusing on the most dangerous (Gayari, 7 April 2012)
3. ✅ What do you know about the 1960 Chile (Valdivia) earthquake? Explain shallow-focus and deep-focus earthquakes
4. ✅ What are volcanic eruptions, and what are their three main types? (Tambora, 1815)
5. What was the magnitude of the 2005 Pakistan earthquake, and where was its epicenter?
6. Explain the Disaster Management Cycle with examples from Pakistan
7. Discuss the causes, impacts and management of the 2022 floods in Pakistan
8. Write a note on glacial lake outburst floods and landslides in Pakistan
9. Discuss Pakistan's disaster management system and the main hazards the country faces
10. Classify earthquakes and volcanoes, with their types, causes and examples

• 📝 Answer outlines
  1. Definition → ≈ 80–86% from seaquakes → three conditions (7.0+, seabed displaced, shallow epicenter) → warning systems → primary and secondary effects
  2. Definition → table of four types → why slab is deadliest → Gayari case (140 dead, ≈ 4,500 m, Siachen)
  3. Valdivia: 22 May 1960, M 9.5, Nazca under South American Plate, Pacific tsunami → table of shallow vs deep focus
  4. Definition → table of shield, composite, cinder cone → effects → Tambora 1815 and global cooling
  5. 7.6 Mw, 8 October 2005, near Muzaffarabad → thrust faulting (Indian under Eurasian plate) → toll 87,000+
  6. Four phases table → NDMA and PDMAs → one Pakistan example per phase
  7. Causes: record monsoon rain, one-third of the country submerged; unregulated construction and deforestation made it worse → impacts: ≈ 1,700 deaths, 33 million affected, ≈ US$30 billion in damage and loss → management: mitigation, early warning, relief and recovery
  8. Definitions → GLOF facts (3,044 lakes, 33 hazardous, over 7 million people threatened, GLOF-II project) → landslide causes → Attabad 2010 → prevention and early warning
  9. Hazard profile (natural and human-induced) → timeline (2005 earthquake, 2006 ordinance, 2007 NDMA, 2010 Act) → three tiers (NDMA, PDMA, DDMA) → cycle with examples → challenges (low spending, weak ownership)
  10. Earthquake: definition → types by cause table → fault types table (normal, reverse, strike-slip) → magnitude vs intensity → Volcano: magma vs lava → six types table → active, dormant, extinct → effusive vs explosive → examples (2005 Kashmir, Tambora 1815)

17. Book Questions: Added Answers

📖

Answers for the book's contents-list questions (Part A, I.c) that were missing or thin on this page. Each answer starts with a written outline, then headings and bullets.

• Book p.28: How do urban fires and wildfires occur and what is the difference between them? (5)

📝

**Outline:** the fire triangle → how an urban fire starts → how a wildfire starts → comparison table → prevention

### 1. What both need

- Every fire needs **heat, fuel and oxygen** (the fire triangle)
- Remove one side and the fire goes out

### 2. How urban fires occur

- Electrical short circuits and overloaded wiring
- Gas leaks and cooking accidents
- Cigarettes, candles and heaters left unattended
- Chemicals and flammable stock in factories and warehouses
- Arson
- It spreads fast through crowded buildings, narrow lanes and flammable materials
- Locked exits and no fire safety turn it into a disaster, as in the Baldia Town factory fire, Karachi (2012, about 260 deaths)

### 3. How wildfires occur

- **Natural causes**: lightning, volcanic activity, prolonged drought and heat
- **Human causes**: campfires, cigarettes, arson, crop-residue burning, sparks from power lines
- It spreads with dry vegetation (fuel), wind and heat, and runs faster uphill
- Embers carried by wind start new fires ahead of the main fire

### 4. Difference between them

| Feature | Urban fire | Wildfire |
| --- | --- | --- |
| Where | Buildings, factories, markets, settlements | Forest, grassland, scrub |
| Fuel | Building materials, furniture, chemicals, wiring, gas | Trees, dry grass, leaf litter, peat |
| Main causes | Short circuits, gas leaks, cooking, cigarettes, arson | Lightning and drought, plus human carelessness and burning |
| Spread | Crowded buildings, narrow lanes, wind | Wind, slope and dry fuel; embers jump ahead |
| Control | Fire brigade, extinguishers, sprinklers, hydrants, building codes | Firebreaks, controlled burns, water-dropping aircraft, satellite detection |
| Main losses | Trapped people, property, smoke injuries | Forest, wildlife, soil, air pollution, carbon emissions |
| Examples | Baldia Town factory fire, Karachi (2012) | Margalla Hills fires in dry summers; Australia's 2019–20 bushfires |

### 5. Prevention

- **Urban**: fire codes, alarms, sprinklers, clear exits, safe wiring and gas fittings, drills
- **Wild**: firebreaks, controlled burns, early detection, awareness, no open fires in dry season

💡

**In simple words:** an urban fire burns what people built, and a wildfire burns what nature grew. Both are the same fire triangle; only the fuel and the place differ.

• Book p.25: Write a note on cyclones. How do they form? Also explain typhoons. (5)

📝

**Outline:** definition and types → conditions and steps of formation → structure → stages and strength → typhoons (hurricane, typhoon, cyclone are one storm) → effects and Pakistan

### 1. Definition and types

- A **cyclone** is a large rotating storm around a low-pressure centre
- It spins counterclockwise in the Northern Hemisphere and clockwise in the Southern
- **Tropical cyclone**: forms over warm tropical oceans
- **Middle-latitude cyclone**: forms along the polar front (see the comparison with tornadoes in the past-paper section)
- **Polar cyclone**: forms in polar regions

### 2. Conditions for formation

- Warm sea surface of about 26.5 °C or more
- Warm, moist, unstable air
- A starting disturbance (a cluster of thunderstorms)
- Distance of at least about 5° from the equator, so the Coriolis effect can make it spin
- Low wind shear, so the storm is not torn apart

### 3. How it forms (steps)

1. Warm ocean water evaporates and warm moist air rises
2. The vapour condenses into clouds and releases heat (latent heat)
3. That heat warms the air further, so it rises faster
4. Pressure at the surface drops, and more air rushes in
5. The Coriolis effect makes the inflowing air spiral
6. A calm **eye** forms in the centre and the storm strengthens

### 4. Structure

- **Eye**: calm, clear centre
- **Eyewall**: ring of strongest winds and heaviest rain around the eye
- **Rainbands**: spiral bands of cloud and rain outside

### 5. Stages and strength

- **Tropical depression**: winds up to 62 km/h
- **Tropical storm**: winds 63–118 km/h (it is given a name)
- **Hurricane, typhoon or cyclone**: winds of 119 km/h or more
- Strength is rated on the Saffir–Simpson scale (Category 1 to 5; see section 8.2)

### 6. Typhoons

- A **typhoon** is a tropical cyclone of the north-west Pacific Ocean
- **Hurricane**: the same storm in the Atlantic and north-east Pacific
- **Cyclone**: the same storm in the Indian Ocean and South Pacific
- Typhoons hit the Philippines, China, Taiwan, Japan and Vietnam, most often from August to October
- A **super typhoon** has winds of about 240 km/h or more

### 7. Effects

- Violent winds destroy homes and power lines
- **Storm surge** (a wall of sea water) causes most deaths
- Heavy rain brings floods and landslides
- Disease, displacement and crop loss follow
- Storms weaken over land or cold water because they lose their warm, moist fuel

### 8. Pakistan

- Arabian Sea cyclones strike mainly in April–June and October–December
- Recent cases: Tauktae (2021) and Biparjoy (2023) near the Sindh coast
- Karachi and the Sindh and Balochistan coast are at risk, and a warming sea is making storms stronger

💡

**In simple words:** a cyclone is a giant spinning engine that runs on warm sea water. Hurricane, typhoon and cyclone are the same storm with different local names.

• Book p.26: Drought is a natural disaster. What do you know about it? (5)

📝

**Outline:** definition and why it is called a creeping disaster → types → causes → effects → Pakistan → management

### 1. Definition

- **Drought** is a long period of below-normal rainfall that causes a water shortage
- It is a **slow-onset (creeping) disaster**: it builds up quietly with no clear start or end
- It can affect very large areas for months or years

### 2. Types

| Type | Meaning |
| --- | --- |
| **Meteorological** | Rainfall well below normal |
| **Agricultural** | Soil moisture too low for crops |
| **Hydrological** | Rivers, lakes and groundwater run low |
| **Socioeconomic** | Demand for water is more than the supply |

### 3. Causes

- **Natural**: failed monsoon, shifts in ocean and air patterns such as El Niño, long-lasting high pressure
- **Human**: deforestation, overgrazing, over-pumping of groundwater, poor water management
- **Climate change**: higher heat means faster evaporation and more erratic rain

### 4. Effects

- Crop failure and food shortage
- Famine and malnutrition
- Livestock deaths
- Desertification
- Forced migration
- More wildfires
- Economic loss and power shortages when dams run low

### 5. Pakistan

- Dry regions: Tharparkar, Cholistan, Balochistan and parts of Sindh
- The severe 1998–2002 drought hit Balochistan and Sindh, and Tharparkar has faced repeated crises
- Pakistan depends on the Indus system, so low snow and rain quickly cut water supply

### 6. Management

- Build dams and reservoirs
- Rainwater harvesting and water recycling
- Drought monitoring and early warning
- Drought-resistant crops and crop rotation
- Efficient irrigation (drip and sprinkler)
- Water-use restrictions and pricing
- Afforestation
- Desalination and cloud seeding where possible

💡

**In simple words:** a drought starts with missing rain, but people make it worse by wasting water and cutting trees. Unlike a flood or earthquake, it creeps up slowly and hurts for a long time.

• Book p.28–29: How can the risk of natural disasters be managed? Explain briefly the points to be considered while coping with the disaster. (5)

📝

**Outline:** risk management idea → before the disaster → during the disaster (points to consider) → after the disaster → Pakistan system

### 1. Managing the risk

- Risk rises with **hazard** and **vulnerability** and falls with **capacity**
- So we cut vulnerability and raise capacity (see the disaster management cycle in section 2.1)
- Steps: identify and assess risk, reduce risk, prepare, then respond and recover

### 2. Before the disaster

- Hazard maps and risk assessment
- Building codes and earthquake-resistant construction
- Land-use zoning (no building in flood plains or on unstable slopes)
- Dams, embankments and flood channels
- Early warning systems and forecasts
- Drills, public awareness and training
- Emergency stockpiles of food, water and medicine
- Insurance and planting trees

### 3. Points to consider while coping with the disaster

- **Speed**: warn people and start rescue as fast as possible
- **Safe evacuation**: move people from danger zones along planned routes
- **Search and rescue** and first aid for the injured
- **Shelter, food, clean water and sanitation** to prevent disease
- **Protect vulnerable groups**: children, women, the elderly and people with disabilities
- **Coordination** among NDMA, PDMAs, DDMAs, the army, Rescue 1122 and NGOs
- **Communication**: clear, true information and no panic or rumours
- **Law and order** and protection of relief goods
- **Fair, transparent** distribution of relief
- **Community participation**, since local people are the first responders

### 4. After the disaster

- Restore water, power, roads and communication
- Medical care and psychological support
- Rehabilitation and reconstruction
- **Build back better**, not just rebuild what was weak
- Learn lessons and update plans
- Warning: very rapid rebuilding can be counter-productive if weak buildings are simply rebuilt

### 5. Pakistan

- **NDMA** at the national level, **PDMAs** in provinces and **DDMAs** in districts (National Disaster Management Act 2010)
- Rescue 1122 provides emergency response
- Weak ownership and low spending are the main challenges

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**In simple words:** the best plan has three parts: get ready before, act fast and together during, and rebuild stronger after.

18. USGS, NOAA and NASA Check and Sources

✅

This chapter was checked against the lecture deck on Natural Hazards and Disasters. Numbers below are corrected to the latest USGS, NOAA, NASA and official Pakistan sources. NASA is the source for the Tonga plume and the FIRMS fire tool; most earthquake and tsunami figures come from USGS and NOAA.

• Not from USGS, NOAA or NASA: Pakistan earthquake dates and tolls (Wikipedia lists, Dawn), 2023–2025 earthquake tolls (Wikipedia lists), the Attabad facts, and the 2026 monsoon counts (NDMA via news reports) are secondary sources, so confirm final figures before the exam

Sources

• USGS Earthquake Hazards Program
• USGS seismic belts (FEMA training copy)
• NOAA/UNESCO tsunami hazard slides
• CNN: Tsunamis fast facts
• NWS: Enhanced Fujita scale
• NHC: Saffir–Simpson wind scale
• NASA: Tonga plume reached the mesosphere
• NASA Earthdata: FIRMS and wildfires
• WMO: Northern Indian Ocean cyclone names
• Green Climate Fund: GLOF risk reduction in Northern Pakistan
• JICA: Pakistan National Disaster Management Plan
• ReliefWeb: Pakistan 2022 monsoon floods final report
• Arab News: IFRC report on the 2025 floods
• Geo News: Germanwatch Climate Risk Index 2026 and Pakistan
• Express Tribune: 2026 monsoon deaths

19. CSS Exam Perspective

🎯

• Most repeated areas: earthquake types and scales, avalanche types, volcano types, disaster management cycle, and named case studies (2005, 2012, 1960, 1815)
• Newer likely areas: Pakistan floods of 2022, 2025 and the 2026 monsoon, glacial lake outbursts, the Kamchatka 2025 earthquake, and the link with climate change
• Short-question style: "What do you know about…", "Differentiate between…", "Describe the four types of…"
• Tip: for each case study, learn date, place, magnitude/type, cause and death toll in one line