Geography and Cartography

1. Cartography: Definition and Symbols

• Cartography: The study and practice of making geographical maps (from Greek chartis = map, graphein = write).
• Map Symbols represent features such as political boundaries, economic zones, geological formations, or temperature variations.
• Symbols types:
  • Areas: forests, countries, temperature zones (often coloured or shaded).
  • Lines: transport routes, rivers, borders.
  • Points: houses, mountain peaks.
• Every map includes a Map Key (Legend) explaining its symbols.

2. Map Scales

• Purpose: Indicate the proportion between the map and the real world.
• Numerical Scale: e.g., 1:50,000 means 1 cm on the map = 50,000 cm (500 m) in reality.
• Graphic Scale: A graduated bar showing distance visually.
• Scale Size:

  Scale Type	Example	Detail Level	Area Covered
  Large scale	1:25,000	Detailed	Smaller area
  Small scale	1:100,000	Less detailed	Larger area

3. Map Projections and Distortions

• The Earth is a sphere; maps are flat → distortions are inevitable.
• Different projections distort size, shape, or distances differently.
• Example: Countries near poles appear larger than reality (e.g., Greenland).
• Only a globe accurately represents Earth's true proportions.
• Common projections:
  • Mercator (1569): Preserves angles, distorts size near poles.
  • Robinson (1963): Balances size and shape distortions.

4. Geographic Coordinate System

• Used to locate places precisely on Earth.
• Parallels (Latitude):
  • Horizontal lines parallel to the Equator (0° latitude).
  • Measure distance north or south from 0° to 90° at poles.
• Meridians (Longitude):
  • Vertical lines from pole to pole.
  • Measure distance east or west from the Prime Meridian (0° longitude, Greenwich).
  • Range: 0° to 180° east or west.
• Coordinates: Given in degrees (°) of latitude and longitude.

5. Key Formulas and Concepts

• Numerical Scale:
  $\text{Real distance} = \text{Map distance} \times \text{Scale factor}$
• Latitude range: $0^\circ$ (Equator) to $90^\circ$ (Poles)
• Longitude range: $0^\circ$ (Prime Meridian) to $180^\circ$ East or West

To locate any place on Earth, use its latitude (north/south) and longitude (east/west) coordinates.

6. Examples of Scale and Detail

• Map of Bern (scale 1:50,000) shows more details (e.g., small roads, buildings) than London (scale 1:200,000).
• Larger scale → more detail, smaller area; smaller scale → less detail, larger area.

7. Comparative Sizes (Atlas-based)

• Africa is nearly twice the size of Russia.
• Greenland is approximately the size of two of these: EU, Saudi Arabia, Australia, or Bolivia.

8. Summary Table: Cartography Essentials

This concise summary covers the essential concepts and tools of cartography needed for understanding and interpreting maps effectively.

1. Map Elements

• Title: Indicates the map’s subject or theme.
• Legend (Key): Explains symbols, colors, and lines used on the map.
• Scale: Shows the relationship between distances on the map and actual distances on Earth.
• Compass Rose (Orientation): Indicates cardinal directions (North, South, East, West).
• Grid: Latitude and longitude lines for locating places precisely.
• Source and Date: Provides information about the map’s origin and when it was created.

2. Map Scales

The scale of a map expresses how much the real world has been reduced to fit on the map. It is crucial for understanding distances and sizes.

a) Types of Scales

b) Scale Categories

3. Key Points on Using Scales

• To calculate real distance:
  $\text{Real distance} = \text{Map distance} \times \text{Scale factor}$
• Large scale maps are best for detailed studies (e.g., urban planning).
• Small scale maps are better for overview and general reference (e.g., world maps).

Remember: The scale determines the level of detail and accuracy of the map’s representation.

4. Summary Table: Map Elements and Their Functions

1. Map Projections and Coordinate Systems

a) Key Concepts of Earth-Sun Relations and Time

• Equinoxes (Spring/Vernal and Autumn): Occur when day and night are equal (12 hours) everywhere; the Sun is directly overhead at the Equator.
• Winter Solstice (around Dec 21-22): Southern hemisphere tilts toward the Sun; the Sun is overhead at the Tropic of Capricorn. The Antarctic Circle experiences 24 hours of daylight, while the Arctic Circle is in darkness.
• Sunrise and Sunset: The Sun appears to rise in the east and set in the west due to Earth's rotation from west to east.

b) Historical Understanding of Earth-Sun System

• Ptolemy (2nd century): Proposed the geocentric model (Sun revolves around Earth).
• Copernicus (15th century): Established the heliocentric model (Earth orbits the Sun).

2. Time Zones and Solar Time

• Solar Time: Based on the Sun’s position; varies continuously with longitude.
• Legal Time: Standardized time within time zones to avoid constant changes.
• The Earth is divided into 24 time zones, each about 15° of longitude, with the same legal time within each zone.
• Time zone borders often follow national or regional boundaries.
• The reference time zone is Greenwich Mean Time (GMT) at the Prime Meridian in Greenwich, London.
• Central European Time (CET) lies directly east of GMT.
• Most clocks use Coordinated Universal Time (UTC), based on atomic clocks, differing slightly from GMT.
• A leap second is occasionally added to UTC to compensate for Earth's slowing rotation.

3. International Date Line and Global Timekeeping

• Traveling west to east across time zones requires setting the clock forward by 1 hour per zone.
• Crossing all 24 time zones results in being one day ahead.
• The International Date Line (in the Pacific Ocean) marks where the calendar date changes when crossed.

4. Summary Table: Time Concepts

The Earth’s rotation and orbit around the Sun create the cycle of day, night, seasons, and the need for standardized time zones.

1. Earth's Movements and Seasons

a) Earth's Internal Structure

The Earth is composed of four main layers, each with distinct properties:

• The Earth's layers are arranged by density: heaviest elements in the core, lighter materials outward.
• The outer and inner cores together make up over 50% of Earth's diameter.

b) Mechanical Layers of the Earth

• Oceanic crust is thinner (~5 km) and basaltic.
• Continental crust is thicker (~35 km) and granitic.

c) Time Zones and Standard Time

• Before the 20th century, local times were based on national observatories, not standardized.
• A global system of standard time zones based on offsets from GMT (later UTC) was gradually adopted worldwide.
• The last country to adopt this system was Nepal in 1986, using UTC+5:45.
• Many countries observe Daylight Saving Time (DST), advancing clocks by one hour in spring to autumn to maximize daylight use.
• DST is currently debated or reconsidered in several countries.

d) Practical Applications of Time Zones

• When traveling or coordinating international events, local times must be converted using time zone offsets.
• Example exercises:
  • Flight from Geneva to Los Angeles: Departure at 2 p.m. Geneva time, flight duration 11 hours → calculate arrival time in Los Angeles local time.
  • Scheduling a Zoom call among Tokyo, New York, and Rome ensuring no participant is before 6 a.m. or after midnight.
  • Calculating local times for events like the World Cup final in different cities using time zones.
  • Comparing times between Australian cities and identifying which observe daylight saving time.

To remember: Earth's internal structure influences surface phenomena, and understanding time zones is essential for global coordination.

1. Time Zones

Time zones are regions of the Earth divided by longitudes where the same standard time is used. They help coordinate time across different geographic areas.

2. Key Concepts

• The Earth is divided into 24 time zones, each roughly 15° of longitude wide, corresponding to one hour of time difference.
• Time zones are based on the Prime Meridian (0° longitude) in Greenwich, England, known as Greenwich Mean Time (GMT) or Universal Time Coordinated (UTC).
• Moving eastward, time advances by one hour per time zone.
• Moving westward, time goes back by one hour per time zone.

3. How Time Zones Work

• The International Date Line (around 180° longitude) marks where the date changes by one day when crossed.
• Some countries adjust their time zones for political, economic, or social reasons, causing irregular time zone boundaries.

4. Daylight Saving Time (DST)

• Some regions adopt Daylight Saving Time by shifting clocks forward by one hour during warmer months to extend evening daylight.
• DST is not universal and varies by country.

To remember:
Each time zone corresponds to 15° of longitude and represents a one-hour difference from the neighboring zones, based on the Prime Meridian at Greenwich.

1. Formation of Oceanic Crust at Divergent Boundaries

• Magma rises at mid-ocean ridges, cools rapidly, and solidifies into basaltic rock.
• Each eruption widens the ridge and adds new crust, causing the oceanic plate to grow over time.

2. Convergent Boundaries: Subduction Zones

• Subduction occurs when two tectonic plates move toward each other and one is forced beneath the other.
• When an oceanic plate collides with a continental plate, the denser oceanic plate subducts beneath the continental plate.
  • Forms deep oceanic trenches.
  • Triggers intense geological activity: melting of subducted plate forms magma, causing volcanic activity.
  • Compression uplifts the continental plate, forming large mountain ranges (e.g., the Andes).
• When two oceanic plates converge, the older, denser plate subducts beneath the younger, creating island arcs (e.g., Aleutian Islands).

3. Convergent Boundaries: Continental Collision

• When two continental plates collide, neither subducts due to similar densities.
• The crust crumples and folds, forming extensive mountain ranges.
• Examples:
  • Alps (African Plate vs Eurasian Plate)
  • Himalayas (Indian Plate vs Eurasian Plate)
• Characterized by intense geological activity (earthquakes, mountain building) but less volcanic activity than subduction zones.

4. Transform Boundaries (Conservative or Strike-Slip)

• Plates slide past each other horizontally along fault lines (strike-slip faults).
• Frequent earthquakes occur due to tension buildup and sudden release.
• Example: San Andreas Fault in California, which may cause southern California to drift northwest over millions of years.

5. Earthquakes

• Result from a sudden release of energy within the Earth's crust, generating seismic waves traveling at 4 to 13 km/s.
• Occur frequently worldwide (~1 million per year), mostly minor.
• Focus: point inside Earth where the earthquake originates.
• Epicentre: point on the surface directly above the focus.

a) Historical Example

• 1356 Basel Earthquake: magnitude 7.1M, most significant seismological event in Central Europe.

b) Earthquake Risk in Switzerland

• Located near the Rhine Rift Valley, a fault zone between African and Eurasian plates.
• Regions at risk: Valais, Basel, Rhine Valley.
• Monitored by the Swiss Seismological Service.

c) Effects of Earthquakes

• Experienced as ground shaking and sometimes ground displacement.
• Offshore epicentres can cause tsunamis.
• Can trigger landslides and sometimes volcanic eruptions.

6. Tectonic Context of Earthquakes

7. Causes of Earthquakes

• Mainly caused by rupture of geological faults or rift zones.
• Other causes: volcanic activity, landslides, mine explosions, nuclear tests.

Key point: Earthquakes result from sudden energy release along faults, generating seismic waves that cause ground shaking and can trigger secondary hazards like tsunamis and landslides.

1. Earthquake Terminology

• Hypocentre (focus): The point inside the Earth where an earthquake originates, usually less than 100 km deep but can be up to 500 km.
• Epicentre: The point on the Earth's surface directly above the hypocentre.

2. Seismic Scales

The Richter scale quantifies energy released; the Modified Mercalli Scale describes observed effects and damage.

3. Earthquake Risk Zones

• Most earthquakes occur along tectonic plate boundaries.
• Crustal deformation causes earthquakes away from faults by slow distortion of the Earth's crust.
• About 90% of tectonic earthquakes occur in the Pacific Ring of Fire, a zone with intense seismic and volcanic activity:
  • Contains 452 volcanoes and over 75% of the world's active/dormant volcanoes.
  • Earthquakes here are usually shallow (within tens of km depth).
• Intraplate earthquakes (away from boundaries) can be devastating (e.g., 1811–1812 Arkansas, 1976 Tangshan).
• Earthquakes also occur near hot spots where magma rises (e.g., Hawaii).

4. Earthquake Preparedness and Risk Reduction

Key measures to reduce earthquake impact:

1. Public education and training
   Teach safe responses (e.g., "Drop, Cover, and Hold On").

2. Urban planning
   Avoid building near fault lines.

3. Earthquake-resistant construction
   Use technologies like rubber base isolators, steel bracing, hydraulic shock absorbers.

4. Securing utilities
   Reinforce water pipes and power lines to prevent secondary disasters.

• These measures require financial investment and long-term planning.
• MEDCs (e.g., Japan, USA) have advanced prevention strategies.
• LEDCs often lack resources, leading to higher casualties and damage.

5. Earthquake Prediction

• Reliable prediction of earthquakes remains impossible.
• Potential precursors studied include:
  • Ground deformation
  • Changes in groundwater levels
  • Magnetic or electric field fluctuations
  • Unusual animal behavior
• No consistent or scientifically reliable method exists to predict the time, location, and magnitude of earthquakes.

Despite research, earthquake prediction is currently not feasible.

1. Earthquake Forecasting and Early Warning

• Probabilistic forecasting estimates the likelihood of seismic activity in a region over a time period, based on historical and geological data.
• Some countries use early warning systems detecting weaker P waves before stronger S waves, providing alerts from seconds to a minute before an earthquake.

Early detection relies on identifying P waves to warn before the more damaging S waves arrive.

2. Volcano Structure and Activity

• A volcano consists of a magmatic chamber beneath the surface connected to the exterior by vertical chimneys.
• Ashes and lava accumulate in chimneys during eruptions.
• Volcanic activity often starts with:
  • Slight ground shaking from magma movement.
  • Expansion of the volcano’s flanks causing surface deformation.
  • Increased volume, temperature, and change in composition of gases released.
• Eruption mechanism: Pressure builds as magma expands; when it exceeds rock strength, magma rises, gases escape, and lava flows on the surface.
• Eruptions end when magma supply stops or pressure drops.
• Volcanoes can remain dormant or inactive for long periods.

3. Classification of Volcanic Eruptions

4. Volcanoes and Tectonic Plates

• Rift volcanoes form where tectonic plates move apart (rifting), often underwater forming mid-ocean ridges.
• Examples: Iceland, East African Rift.
• Lava is mainly basaltic: heavy, fluid, low silica and gas content.
• Eruptions are effusive: steady, smooth lava flows without violent explosions.
• Typical shape: shield volcano — broad, gently sloping from layered lava flows.
• Such volcanoes are considered "calm" or "wise" due to their gentle activity.

Volcano eruptions vary greatly in violence and style, depending on magma composition and tectonic setting.

1. Subduction Volcanoes

• Location: Found in subduction zones where an oceanic plate sinks beneath a continental plate.
• Formation process: Oceanic crust melts under high temperature and pressure, mixing with sediments saturated with water, creating magma.
• Magma ascent: Magma rises through ~80 km of continental crust, becoming chemically complex and viscous.
• Lava type: Andesite lava, thick and sticky.
• Eruption style: Explosive due to high silica, water, and gas content; gases escape as pressure decreases, accelerating magma.
• Volcano type: Stratovolcanoes (composite volcanoes) with steep-sided cones formed by alternating layers of lava, ash, and debris.
• Nickname: "Grey" volcanoes because of ash and pumice emissions.
• Example: Mount Saint Helens (USA).
• Eruption style example: Strombolian eruptions.

2. Hot Spot Volcanoes

• Location: Within tectonic plates, not at boundaries.
• Formation: Mantle plumes (hot molten rock columns) rise and pierce Earth's crust.
• Lava type: Basaltic lava with low silica and gas content.
• Eruption style: Effusive eruptions with steady lava flows.
• Volcano type: Shield volcanoes with broad, gently sloping shapes.
• Example: Hawaiian Islands.
• Nickname: "Red" volcanoes due to calm, steady lava flows.

3. Matter Ejected by Volcanoes

4. Volcanic Structures and Features

Key point: Subduction volcanoes produce explosive eruptions with viscous andesite lava, while hot spot volcanoes produce effusive eruptions with fluid basaltic lava.

1. Tsunamis

A tsunami is a large sea wave caused primarily by underwater earthquakes that displace a significant volume of water. The term originates from Japanese.

• Formation: When an earthquake occurs beneath the oceanic crust, it displaces water, generating waves that are small in deep water but grow dramatically near the coast.
• Wave height: Can reach up to 30 metres near shore.
• Speed: Tsunami waves travel between 500 and 800 km/h.
• Warning signs: The sea often recedes dramatically before the wave arrives.
• Multiple waves: Several waves can strike one after another, increasing the danger.

a) Causes of Tsunamis

b) Examples of Tsunamis

Key fact: Tsunamis may strike hours after the triggering earthquake, making early warning and preparedness crucial.