1.8A - Prediction and Forecasting
Prediction and forecasting (p: role of scientists) accuracy depend on the type and location of the tectonic hazard.
Prediction means knowing when are where a natural hazard will strike on a spatial and temporal scale that can be acted on meaningfully in terms of evacuation.
Forecasting is much less precise than prediction, and provides a percentage change of a hazard occurring (e.g. a 25% of a magnitude 7.0 earthquake occurring in the next 20 years)
Earthquakes
- Cannot be predicted (despite decades of scientific research)
- Only areas at high risk can be identified (risk forecasting), plus areas that are likely to suffer severe ground shaking and liquefaction; this can be used for land-use zoning purposes
- 'Seismic gaps', i.e. areas that have not experienced an earthquake for some time and are 'overdue' can point to areas of high risk
- Can be predicted
- Sophisticated monitoring equipment on volcanoes can measure changes as magma chambers fill and eruption nears
- Tiltmeters and strain meters record volcanoes 'bulging' as magma rises and seismometers record minor earthquakes indicating magma movement
- Gas spectrometers analyse gas emissions which can point to increased eruption likelihood.
- The minimal death toll from volcanic eruptions (despite 60-80 eruptions per year) can be mainly attributed to vastly improved prediction of these events.
- Can be partly predicted
- An earthquake-induced tsunami cannot be predicted
- However, seismometers can tell an earthquake has occurred and locate it, then ocean monitoring equipment can detect tsunami in the open sea
- This information can be relayed to coastal areas, which can be evacuated.
Prediction of tsunami and eruptions depends upon technology, which has to be: in place, operational and linked to warming dissemination and evacuation systems
Tsunami monitoring equipment was not present in the Indian Ocean in 2004 so there wasn't a way of warning people on distant coasts - despite there being many hours in which to have done so.
In many developing countries, volcano monitoring and tsunami warning may not be as good as they could be because of the cost of technology. Also, it may be more difficult to reach isolated, rural locations with effective warnings.