Earthquakes and tsunamis can have an enormous impact. The degree of impact can be affected by several factors: the size of the quake, its location, the density of the population near the epicentre and whether there are any densely populated areas nearby. Poverty also plays a role, because it can increase a country’s or region’s vulnerability to such disasters. Measuring an event by the impact can be difficult. Should it be measured by the number of people killed and made homeless (social impact); the cost of recovery (economic impact) or the effect on the surroundings (environmental impact)? 14.8.1 Impact on people Thedata in FIGURE3 shows some of the worst earthquake and tsunami disasters that have occurred in history. The amount of damage and death they cause does not always relate to the magnitude of the earthquake. Some smaller-magnitude earthquakes can have a devastating impact. Likewise, to measure the impact of a tsunami, we have to look at its effect on people — not at the magnitude of the earthquake (or volcano) that caused it, nor at the size of the waves, which are difficult to measure.
TABLE1 Why natural disasters have bigger impacts in less developed nations Less economically developed nation
More economically developed nation
• Lack of resources to prepare for a disaster • Poorly constructed buildings are more common • Higher population density on poor (often low-lying) land • Less money to organise relief efforts • Less infrastructure to deal with a relocated population and likely medical needs • Less financial resources to help in the post-disaster period
• Better building codes to help ensure less damage from earthquakes • More comprehensive warning systems • Organisations like NEMA (National Emergency Management Agency) in Australia and FEMA (Federal Emergency Management Agency) in the United States of America with better resources • Better health infrastructure • More financially able to offer support to those affected
Analysis of EM-DAT (The International Disaster Database) data also shows how income levels have an impact on disaster death tolls. On average, more than three times as many people died per disaster in low-income countries (332 deaths) than in high-income countries (105 deaths). A similar pattern is evident when low- and lower-middle-income countries are grouped together and compared to high- and upper-middle-income countries. Taken together, higher-income countries experienced 56 per cent of disasters but lost 32 per cent of lives, while lower-income countries experienced 44 per cent of disasters but suffered 68 per cent of the deaths. This demonstrates that levels of economic development, rather than exposure to hazards, are major determinants of mortality. 14.8.2 Impact on the natural environment The impact of an earthquake or tsunami on a natural environment can be catastrophic. Sea water can impact forest environments. Landslides can be triggered by earthquakes, permanently changing the landscape, and freshwater ecosystems can be inundated by sea water as a result of tsunamis.
TOPIC14 Geomorphological processes and hazards
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