Weather: State of the atmosphere in a location for a short period, influenced by temperature, humidity, precipitation, air pressure, and cloud cover.

Climate: Average weather over 30+ years. Influenced by geographic location and wind patterns (e.g., El Niño, La Niña).

Flooding: Can be natural and periodic or sudden/severe, causing massive loss. By 2050, predicted cost increase of $11 billion. Caused by heavy rainfall and rivers bursting banks.

Wildfires: Long rainfall promotes vegetation growth (fuel). Dry, hot seasons plus winds and lightning can cause rapid fires.

Hurricanes: Result from higher sea temperatures and rising sea levels due to climate change.

Tornadoes: Caused by drastic climate changes producing severe storms and intense atmospheric conditions.

Losses per continent (1970–2019):

• Africa: $5B losses, 15% of global weather/climate disasters, 60% floods, droughts caused 95% deaths.
• Asia: $2T losses, 31% of global weather/climate disasters.
• South America: $39.2B losses, 59% floods.
• North America + Caribbean: $1.7T losses, 38% of global.
• South West Pacific: $88.2B losses.

The Earth’s crust consists of tectonic plates, whose movement causes earthquakes, volcanoes, tsunamis, and mountain formation. Plate movement is driven by density differences between oceanic and continental crust.

Plate boundaries: Convergent, Divergent, Transform.

Convergent boundaries: Two plates collide.

• Continental-Continental: Fold mountains (e.g., Himalayas)
• Oceanic-Continental: Oceanic plate subducts, forms volcanoes, earthquakes due to friction

Transform boundaries: Plates slip past each other along fault lines, producing earthquakes.

Sudden shaking of Earth’s surface from energy release in the lithosphere. Hypocentre (focus): underground origin. Epicentre: surface location above the hypocentre.

Types of seismic waves:

• P-waves: Primary longitudinal waves, move through solids & liquids.
• S-waves: Secondary transverse waves, only through solids, more destructive.
• Surface waves: Love (shearing zig-zag motion) & Rayleigh (elliptical rolling motion).

Magnitude vs Intensity:

• Intensity: Relative shaking, based on human observation, location-dependent.
• Magnitude: Numerical measurement, seismograph-based, constant with distance. Measured via Richter or Moment Magnitude Scale.

Effects depend on magnitude, depth, distance, population density, preparedness, and time of day. Includes primary effects (casualties, infrastructure) and secondary effects (fires, sanitation issues, transport disruption, landslides, tsunamis, liquefaction).

Short-Term: Rescue operations, field hospitals, clean food & water, temporary shelter, extinguishing fires, warnings for aftershocks & tsunamis.

Long-Term: Prediction, protection, preparedness.

• Prediction: Seismometers, tiltmeters, remote sensing (InSAR), GIS hazard mapping.
• Protection: Earthquake-resistant buildings, rubber shock absorbers, flexible pipelines, open evacuation areas, land use planning.
• Preparedness: Drills, education, training, communication in local language.

An earthquake-resistant building example.

Causes:

• Transform fault along the Caribbean Plate and North American Plate near Haiti
• Epicentre close to Port-au-Prince
• Shallow hypocentre (10 km beneath surface)
• 7.0 magnitude earthquake on Richter Scale

Background Vulnerabilities:

• Lack of land-use zoning and building codes
• Poverty: average income < $2/day, limiting earthquake-resistant construction
• Corruption: contractors build on unstable land
• Poor infrastructure: majority live in shantytowns

Impacts: Short-Term:

• U.N. agency buildings damaged, affecting aid and medical treatment
• Damage to seaports obstructed rescue operations
• Communications infrastructure heavily damaged
• 1-3% of population killed
• Lack of earthquake-resistant structures caused building collapses

Long-Term:

• Cholera outbreak introduced via U.N. volunteers and Peacekeepers
• Recovery efforts created large volumes of plastic waste, clogging drainage
• Homelessness and long-term infrastructure loss

Response:

• $3.06 billion donated by private donors to U.N. agencies
• Only 48% of aid reached Haiti; delays and redirection of funds
• Canada and Dominican Republic accepted Haitian refugees
• OpenStreetMap improved mapping using satellite images
• Search-and-rescue, food aid, and medical teams from around the world

Origin: Japanese words “tsu-” (harbour) + “-nami” (wave). Series of oceanic waves with extremely long wavelengths and periods.

Triggered by seismic activity, underwater volcanic eruptions, or landslides (e.g., Mediterranean, Greek islands).

Formation:

• Underwater earthquakes displace large water volumes
• Volcanic eruptions and landslides also displace water
• Energy travels from seafloor through deep pelagic zone to surface-level benthic zone
• Shallow areas cause wave height to increase (destructive)
• Long backswash occurs before wave arrives

Classification:

• Local: ≤100 km from shore; less devastating but <1 hour warning
• Regional: ≤1000 km from shore; 1–3 hour warning
• Distant / Tele-tsunami: >1000 km from shore; most devastating

2004 Indian Ocean Tsunami:

• 9.1 magnitude earthquake, 900 km away from affected areas
• 230,000 deaths; >500,000 displaced
• Tele-tsunami affected South India & East Africa
• Subduction of Indo-Australian plate under Eurasian plate
• Water traveled ~2 km inland in Sumatran coast
• Consequences: PTSD, cholera, dysentery, typhoid, reduced tourism, change in day length (2.368 sec)
• NGOs provided 11,000 shelters; basic aid due to LEDC status

Effects: Flooding, water contamination, vector-borne diseases, environmental destruction, infrastructure loss, disruption of livelihoods, chemical contamination.

Technology:

• Tsunami Alarm System: seismic detectors, GSM alerts
• D.A.R.T. buoys: buoy, anchor, tsunameter; detect abnormal water pressure, transmit data via satellite

Causes:

• Subduction zone earthquake: Pacific plate subducted under Okhotsk plate
• Okhotsk plate stuck, pressure buildup, seafloor uplift
• Seismic wave release caused drop in seafloor, displacing water → tsunami
• Waves reached Honshu coast in under 30 minutes

Background Vulnerabilities:

• Japan located on complex plate boundary with many fault lines
• Sparsely populated initial area → fewer casualties
• Shallow hypocenter: 32 km depth

Impacts: Short-Term:

• 9.0 magnitude earthquake
• Fukushima nuclear disaster: flooding, reactor meltdown, radioactive release
• 16,000 deaths, 6,000 injured
• Loss of property & infrastructure, lack of clean food, water, fuel
• $316 billion economic damage (excluding private sector)

Long-Term:

• North & South America affected: waves reached South America ~21h later, North America 6–9h later
• Power blackouts due to nuclear loss, food shortages, radiation contamination
• Difficult rebuilding: missing leadership, mental trauma, environmental damage
• Loss in sales & production of Japanese companies

Response:

• Assistance from 163 countries
• Operation Tomodachi (U.S.) – aid mission
• Japanese Self-Defense Forces for search & rescue and clearing roads
• Red Cross and other organizations provided relief
• Team Fortress 2 in-game donations (yes, really!)

A volcano is a vent/fissure in the Earth’s surface where molten rock, hot gases, and rock fragments erupt.

Types:

• Shield volcanoes: broad, low-profile, fluid lava, frequent eruptions, dormant periods, hotspots
• Stratovolcanoes: steep, conical, layers of erupted material, explosive eruptions, lahars
• Cinder cones: small, steep-sided, loose pyroclastic material
• Dome volcanoes: thick, fast-cooling lava, dome-shaped
• Fissure volcanoes: simple cracks, non-explosive
• Caldera volcanoes: violent, explosive, bowl-shaped depression

Volcano Parts:

• Magma chamber/reservoir: source of magma
• Opening/vent/fissure: surface exit for magma
• Crater: bowl-shaped depression at summit
• Lava flows: molten rock streams down slopes
• Pyroclastic material: ash, gas, rock fragments; includes pyroclastic flows
• Ash clouds: travel long distances, affect air quality, contribute to acid rain
• Crater lakes: formed in calderas after eruption
• Parasitic cones: secondary vents affecting volcano shape
• Flank: sloping sides built from eruptions

Types of Eruptions:

• Icelandic: lava mixes with ice, empties into oceans
• Hawaiian: step-like structures, frequent eruptions, material blown off forms steps

The majority of the world’s volcanoes are located on subduction zones or divergent plate boundaries.

> The red dots represent volcanoes.

Subduction Zones:

• Denser oceanic crust forced beneath lighter continental crust
• Subducted crust melts into magma in the mantle

Divergent Plate Boundaries:

• Two plates move apart, magma rises from mantle and solidifies into mid-ocean ridges
• Underwater volcanoes can emerge above sea level

Hot Spots:

• Volcanoes far from plate boundaries (e.g., Hawaii)
• Formed by magma plumes beneath Earth’s crust
• As a plate moves over a plume, multiple volcanoes or islands form (island chains)

Volcanoes expel molten rock, hot gases, and rock fragments through vents. Lava flows can burn everything in their path, so timely evacuation is essential.

Common Eruption Features:

• Pyroclastic flows: Avalanches of ash, gas, and hot material, up to 1500°F, impossible to outrun
• Lahars/mudflows: Currents of mud, sand, rock, ash, water; coarse debris moves at top speeds, depositing mud downstream

Positive Impacts:

• Geothermal energy: Extract energy from magma; first 10 km below U.S. soil contains 3.3 × 10^25 joules (~6,000x world oil reserves)
• Ash as fertilizer: Long-term soil enrichment aiding agriculture
• Tourism: Volcanoes attract tourists (e.g., Bali)

LEDCs vs MEDCs: LEDCs are 20x more affected in GDP terms; lack monitoring equipment and experts to analyze volcanic activity.

Short-Term:

• Social: Casualties, displacement, property damage
• Environmental: Air/water contamination, habitat destruction
• Economic: Reconstruction costs, loss of income, emergency response costs
• Political: Unrest, riots, looting if law enforcement disrupted

Long-Term:

• Social: Mental health issues, cultural site destruction, increased homelessness
• Environmental: Greenhouse gas emissions contribute to global warming
• Economic: Disruption of economic growth, deeper economic divide
• Political: Introduction of disaster management policies, improved evacuation and relocation strategies

Short-Term Responses:

• Evacuation
• Emergency aid and medical facilities
• Search-and-rescue operations

Long-Term Responses:

• Land use zoning and relocation
• New building codes
• Education, training, safety drills

Preparedness & Mitigation:

• Preparedness: Early warning messages, safety drills (e.g., Philippines text warnings)
• Mitigation: Redirect lava flows, construct protective barriers (e.g., Iceland “volcano wall”)
• Adaptation: Change lifestyle post-disaster (e.g., Montserrat promoting tourism)

Monitoring Volcanoes:

• InSAR: Track ground deformation, gas emissions, heat signatures, ash plumes
• Gas sensors and drones: Safer, cheaper monitoring
• Volcanic alert systems (e.g., VNS in Hawaii) with color-coded warnings

Types of Floods:

• River floods (e.g., Musi River)
• Urban floods (poor drainage, Mumbai, Chennai)
• Flash floods (rapid low-lying area inundation)
• Coastal floods (cyclones in Bay of Bengal)

Causes:

• Natural: Heavy rainfall, snowmelt, storm surges, tsunamis
• Human-aggravated: Deforestation, poor urban planning, dam failures, climate change

Impacts:

• Environmental: Soil erosion, water contamination, habitat destruction, sedimentation
• Social: Displacement (e.g., 5.7M in 2020 Assam floods), waterborne diseases, infrastructure damage
• Economic: Loss of agriculture, workplaces, productivity; India loses ~Rs. 95,000 annually
• Mental trauma and PTSD

Solutions:

• Constructing and preserving wetlands to absorb excess water
• Wetlands as carbon sinks, recreational areas, biodiversity support

Cyclones are tropical storms that occur in the tropics (Cancer & Capricorn). Warm ocean water and low-pressure zones drive formation.

Formation:

• Uneven solar heating → low pressure at tropics, high pressure at poles
• Warm air rises over oceans, condenses into clouds, releases heat
• Coriolis force from Earth’s rotation deflects air, causing spinning motion (~15° deflection/hour)

The Eye:

• Low-pressure region at the centre attracting cool, high-pressure air
• Warm air rises, creating a vacuum; cool air rushes in, heats, and rises again
• Some air cools and sinks, creating fair weather in the eye

Eyewall:

• Ring of dense condensation around the eye
• Contains most severe thunderstorms and heavy rainfall

Environmental:

• Coastal erosion
• Saltwater intrusion contaminates freshwater sources
• Loss of vegetation and habitats
• Marine disruption – sediment chokes coral reefs
• Heat distribution: cyclones move heat from equator to poles

Social:

• Casualties and mental trauma
• Damage to infrastructure and communications
• Health risks due to poor sanitation and stagnant water
• Displacement and overcrowding in shelters

Economic:

• Immediate and long-term losses from industry destruction and lost tourism
• Redirection of funds to recovery
• Damage to workplaces → loss of income

Cyclone Fani – India:

• GIS used for planning and evacuation to avoid traffic congestion
• Real-time path monitoring and prioritization of evacuations
• High-quality satellite imagery helped post-disaster planning

Cyclone Amphan – India & Bangladesh:

• 4.9M displaced, $13.5B economic damage
• Exposed poor urban planning in coastal regions
• Impact: 128 deaths, 1M homes destroyed, saltwater intrusion in Bangladesh, agricultural losses
• Response: cyclone preparedness, evacuation, need for cyclone-resistant housing, restoration of Sundarbans

1991 Bangladesh Cyclone (Gorky):

• Background vulnerabilities: underestimation, high tide, dense population, lack of natural barriers
• Short-Term Impacts: 138,000 deaths, 80–90% homes destroyed, homelessness, diarrhea and respiratory issues, livestock loss
• Long-Term Impacts: contamination of drinking water, destruction of farms, gender disparities in casualties
• Response: Operation Sea Angel (international aid), reforestation, elevated shelters, BISAP program for reconstruction and WaSH facilities

Mitigation: Reduce disaster impact; examples include land use zoning, retrofitting structures

Preparedness: Plan responses using early warning systems; train NGOs and local authorities

Response: Immediate action; use technology for real-time info, GPS on emergency vehicles, portable radars (e.g., NASA FINDER)

Recovery: Rebuild and restore normalcy; physical reconstruction and socioeconomic redevelopment using GIS and satellite imagery

Challenges: Lack of long-term institutions, insufficient integration into policymaking, overemphasis on physical recovery without socioeconomic context

Hyogo Framework (2005–2015):

• Promote individual state responsibility + global collaboration
• Inclusive, non-discriminatory disaster planning
• Improve local access to hazard knowledge
• Five priorities: Risk reduction priority, know risks & act, awareness building, reduce risk, preparedness

Sendai Framework (2015–2030):

• Guiding principles: shared responsibility, inclusivity, address underlying risk factors
• Main outcome: reduce disaster risk and asset loss
• Main goal: prevent new/emerging risks and reduce existing risks
• Four priorities: Understand risk, strengthen governance, invest in DRR, enhance preparedness
• Seven targets: reduce mortality, reduce nonfatal impacts, reduce GDP losses, reduce infrastructure damage, increase DRR strategies, increase international cooperation, increase early warning access