1.7A - Trends since 1960

Tectonic disaster trends since 1960, (number of deaths, number affected, level of economic damage) in the context of overall disaster trends; research into the accuracy and reliability of the data to interpret complex trends. 

The numbers of disasters and the impacts of disasters are not static. There is, however, a difference between the two broad categories of natural hazard:
  1. Hydro-met hazards, such as floods, storms, cyclones and drought, appear to have become more common over time, perhaps because of global warming and human environmental management issues such as deforestation. 
  2. Tectonic disasters, i.e. the events, have not increased or decreased over time. The number of events is broadly the same decade over decade. 

Tectonic hazards and tectonic disasters are not the same, so even though the number of hazard events remains stable, the number of disasters has risen. 

Three trends for all disasters:
  1. Deaths have fallen over time because of better response management, preparation and, in some cases, prediction. Numbers of deaths have fallen, especially since 2000, which may be due to vastly improved mobile communications to warn people about disasters. 
    1. More than 120,000 in 1975-> 90,000 in 1980 (biggest drop!)-> about 70,000 in 2000 -> 20,000 in 2015. (decrease of more than 3000 each year)
  2. The number of reported disasters increased then stabilised as improvements in data coverage and the accuracy of databases increased. Decades ago, many disasters in isolated areas simply went unreported. More recently, the number of reported disasters have fallen, suggesting fewer hazard events are becoming disasters. 
    1. About 900 in 1975 -> increases until reaching 450 in 2003 -> decreased to about 360 in 2012, and seems to have stabilised
  3. The number of people affected by disasters continues to rise as populations grow and more people live in risky locations.  
    1. 55 million 1975 -> 190 million 1995 (most rapid increase) -> 260 million 2015 (slower rate of increase)

Trends in tectonic hazards can be summarised as follows:
  • There has been no change in the number of earthquake disasters since 1980, which varies between 15 and 40 each year. 
  • Earthquake deaths are very variable: there were fewer than 1000 deaths worldwide in 2012 and 2014, yet more than 200,000 in 2010 and 2004. Overall, there are fewer earthquake deaths than there were 30-40 years ago, but the impact of single megadisasters skews the data. 
    • Megadisasters are high-magnitude, high impact, infrequent disasters that affect multiple countries (directly or indirectly), so their impacts are regional or even global.
  • The trend for earthquake economic losses is upwards, averaging about $20-40 billion per year but, once again, this is affected by very few large events. 

Economic losses from tectonic disasters continues to rise. More people, who are more affluent, have more property to lose. This is increasingly true in emerging countries as well as developed ones. 

Volcanic disasters are much less frequent than earthquake ones and deaths from eruptions are now rare. The last time an eruption killed more than 1000 people was in Cameron in 1986 (Lake Nyos) and only seven eruptions since 1980 have killed more than 100 people. However, numbers affected can be very large because of the mass evacuation of people around an erupting volcano, e.g. 350,000 affected (evacuated) with the eruption of Mt Merapi in Indonesia in 2010, but only 300 deaths.