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Unlock This CourseMaps are powerful tools that help us understand where natural hazards occur around the world. By showing the distribution of earthquakes, volcanoes, floods and other hazards on maps, we can spot patterns, predict future risks and plan how to protect people and property. This is essential knowledge for governments, emergency services and communities living in hazardous areas.
Key Definitions:
Mapping hazards helps us identify high-risk areas, plan evacuation routes, decide where to build hospitals and schools and allocate emergency resources. It's like having a crystal ball that shows us where danger might strike next!
Different types of maps show hazard information in various ways. Each type has its own strengths and is useful for different purposes.
These maps use dots or symbols to show the exact locations where hazards have occurred. Each symbol represents one event, like an earthquake or volcanic eruption. The size of the symbol might show the magnitude or intensity of the event.
Shows precise locations, easy to understand, good for showing individual events and their exact positions.
Can become cluttered with too many points, doesn't show risk levels for areas without events.
Earthquake epicentres, volcano locations, landslide sites, tornado paths.
These maps use different colours or shading patterns to show hazard risk levels across different areas. Darker colours usually mean higher risk. Think of weather maps showing temperature - it's the same idea but for hazards!
The Environment Agency creates choropleth maps showing flood risk across England. Areas are coloured from light blue (low risk) to dark blue (high risk). These maps help people buying houses understand flood danger and help councils plan flood defences. The maps combine data on rainfall, river levels, coastal flooding and land height to create accurate risk assessments.
These maps use lines to connect points of equal hazard intensity. It's like the contour lines on a hiking map, but instead of showing height, they show things like earthquake intensity or volcanic ash thickness.
These show earthquake intensity using curved lines. Areas inside the same line experienced similar shaking intensity. The closer to the epicentre, the higher the intensity numbers.
Understanding map symbols is crucial for interpreting hazard distribution correctly. Every good hazard map includes a legend that explains what each symbol, colour, or pattern means.
Usually shown as circles or stars. Size indicates magnitude, colour might show depth or age of the earthquake.
Triangular symbols, often red or orange. Different symbols might show active, dormant, or extinct volcanoes.
Blue shading or hatching. Different intensities of blue show different flood risk levels or historical flood extents.
The scale of a map affects what patterns you can see. A world map might show global patterns like the Ring of Fire, whilst a local map shows exactly which streets flood during heavy rain. Map projections can also distort the apparent distribution of hazards, especially near the poles.
Today's hazard mapping uses advanced technology that would have seemed like magic to early cartographers!
GIS allows scientists to layer different types of data on top of each other. They might combine earthquake data with population density, building types and soil conditions to create comprehensive risk maps.
After the 2011 Tōhoku earthquake and tsunami, Japan updated its hazard maps using GIS technology. The new maps combine seismic data, tsunami modelling, population data and building vulnerability assessments. Citizens can access these maps online to understand their personal risk levels and plan accordingly. The maps are updated regularly as new data becomes available.
Satellites can detect changes in land surface that might indicate hazard risk. They can spot ground movement before earthquakes, measure volcanic gas emissions and track wildfire spread in real-time.
Modern hazard maps can be updated in real-time. Earthquake maps show new tremors within minutes and flood maps update as river levels change. This helps emergency services respond quickly to developing situations.
Once you can read hazard maps, you need to understand what the patterns tell us about the underlying causes of natural hazards.
Looking at world hazard maps reveals clear patterns. Earthquakes and volcanoes cluster along plate boundaries, forming features like the Pacific Ring of Fire. Tropical cyclones occur in specific latitude bands and droughts often affect similar climate zones.
At smaller scales, hazard distribution relates to local geography. Floods follow river valleys and low-lying areas. Landslides occur on steep slopes, especially those with certain rock types or vegetation patterns.
Follow plate boundaries - constructive, destructive and conservative margins each have characteristic hazard patterns.
Related to latitude, altitude, distance from sea and prevailing wind patterns.
Linked to slope angle, rock type, soil conditions and human activities like deforestation.
Understanding how to create simple hazard maps helps you better interpret professional ones and can be useful for local risk assessment.
Start with a base map of your area, collect hazard data from reliable sources, choose appropriate symbols or colours, create a clear legend and add a scale and north arrow. Always include your data sources and the date the map was created.
Students can create a simple flood risk map of their school grounds by identifying low-lying areas, noting drainage patterns, marking areas that flood during heavy rain and using different colours to show risk levels. This hands-on approach helps understand both mapping techniques and local hazard assessment.
Reliable data comes from government agencies like the British Geological Survey, Met Office and Environment Agency. International sources include the US Geological Survey and various UN agencies. Always check that data is recent and from authoritative sources.
Good hazard maps are accurate, up-to-date, clearly labelled, appropriately scaled and designed for their intended audience. They should tell a clear story about hazard distribution without overwhelming the reader with unnecessary detail.