Scientists have released the most detailed map yet of our planet's earthquake hazard zones.

The map, which has taken 500 researchers more than five years to produce, shows that much of the world's population is living in potentially dangerous locations.

The colourful document will provide new information that can be used by national and local governments to decide where to build and regulate the standards of design and construction.

Some nations in Africa, for example, have never compiled such data themselves.

"We can say today that as a result of this programme, more than half the countries of the world have a new generation of seismic hazard maps,'' said Professor Domenico Giardini of the Swiss Seismological Service in Zurich.

Ground acceleration

As much as 15% of the planet's land is in zones of high or very high hazard, which is defined as a 10% chance or greater of violent shaking within the next 50 years.

Roughly 40% of the Earth's land is considered low hazard.

Specifically, the map attempts to predict the probability of peak ground acceleration, a force that is most likely to damage low-rise residential buildings. Future maps are being compiled that will detail hazard areas for larger structures like high-rises and skyscrapers.

"This map only provides part of the story,'' Professor Giardini said. "You can easily live in a high-risk area if you have a well-built house.''

The Global Seismic Hazard Assessment Programme (GSHAP) was launched in 1992 by the International Lithosphere Programme (ILP) with the support of the International Council of Scientific Unions (ICSU), and endorsed as a demonstration programme in the framework of the United Nations International Decade for Natural Disaster Reduction (UN/IDNDR).

Biblical passages

Researchers combined existing hazard maps, data from recent and historical quakes as well as other records that stretch back 2,000 years. Biblical passages were even used for parts of the Middle East.

The work was easy in more developed countries such as the US, where the law requires hazard maps to be updated every five years. It was much more difficult in less developed countries, Professor Giardini said.

The greatest hazard areas, coloured red or brown on the map, contain half the world's largest cities. Efforts are now under way to determine exactly how many people live in the most dangerous areas.

Dr Roger Musson, seismic hazards expert at the British Geological Survey, said the map would provide vital data to three groups:

• Engineers - Earthquake casualties can be reduced if building codes are sufficiently strict
• Planners - Politicians need to plan an emergency response for when an earthquake strikes
• Insurers - Reconstruction after an earthquake is paid for by insurance

Dr Musson told BBC News Online: "Engineers need to understand how bad the hazards are because their buildings must be safe. On the other hand, if they over-design their buildings, they will become uneconomic.

"Planners clearly need prepare for a disaster, and an insurer will want to work out at what level premiums should be set.

"The map will be very good at telling you whether or not you have a problem and what the magnitude of that problem is likely to be."

The map was unveiled at the annual meeting of the American Geophysical Union.