GIS Provides a Desktop View of Worldwide Disasters

When Nature Strikes

While science and technology have thus far been unable to provide us with the means of mitigating a natural disaster before it strikes, they have given us significant tools to help determine its probability, which in turn allows us to take precautionary measures.

Aside from the devastating human toll, windstorms, earthquakes, storm surges, hail, lightning, and other natural events cause extensive physical damage amounting to billions of dollars every year. Fortunately, much of this damage is covered by insurance and reinsurance companies.

For more than 20 years, the geoscientists at Munich Reinsurance Company (Munich Re) of Munich, Germany, have been producing the World Map of Natural Hazards, a cartographic representation of the distribution and intensity of the most significant risk potentials for natural disaster throughout the entire world.

Munich Re's maps are used as an aid in risk-commensurate underwriting, catastrophe prevention, and public planning. In the latest edition, the maps have been brought up-to-date using the most accurate and current scientific data available, using state-of-the-art techniques including GIS technology, satellite data, and risk analysis programs.

All base-level data in the latest edition was captured, adjusted, and analyzed using ArcInfo and ArcView GIS software. The maps derived from this data were produced exclusively with digital cartography techniques, which allowed easy editing and a quick final production.

A publication accompanying the World Map of Natural Hazards discusses relevant underwriting aspects and presents a comprehensive history of natural catastrophes around the world. The events are broken down by continent and presented in chronological order with additional information such as the number of fatalities and, wherever possible, the economic losses. The locations and distribution of the catastrophic events are also presented on regional maps.

To present this large volume of information, four auxiliary maps were added to the main map including severe rainfall and lightning, climatic change, tropical windstorms, and plate tectonics.

A variety of methods were used in recording and analyzing the thunderstorm data. Satellite photographs were used, for example, to determine possible lightning exposure, which was then compared with observation data from ground-based lightning detection networks.

The auxiliary map on climate change is considered a real innovation. It not only deals with the effects of El Niño, which attracted enormous attention the world over in 1997–98 as it triggered numerous natural catastrophes, but also shows some of the effects that global warming is expected to have on natural hazards.

The exposure to tropical windstorms was determined using a risk analysis program especially developed by Munich Re. The values were then classified and visualized in exposure zones on the basis of windstorm intensity. In addition to exposure zones, the auxiliary map includes the main tracks of tropical and extratropical windstorms. Other windstorm maps provide information on the exposure to tornadoes and regional windstorm systems like the Chinook, Mistral, and Föhn. Coastal exposure to storm surges, combined with seismic sea waves (tsunamis), is also presented.

Earthquakes are generally regarded as the most destructive force of nature. To represent global earthquake exposure according to its intensity, numerous regional and local investigations were related to a uniform exceedence probability. Other geophysical aspects of earthquakes include particularly dangerous volcanoes and the exposure of cities to subsoil resonance effects. Since more than 90 percent of all earthquakes happen in areas where large tectonic plates converge, an auxiliary map of plate tectonics was produced to give deeper insight into this subject.

It is well known that the Middle East region is seismically active, with the Red Sea forming the boundary between the African and Arabian Plates. By making use of localized natural hazard maps like those produced by Munich Re, Middle Eastern insurance companies can make better evaluations of potential earthquake exposure throughout the region.

Sitting astride the Dead Sea Transform, the western boundary to the Arabian plate, Lebanon has historically suffered from strong earthquake activity. Early in the fourth century, a series of earthquakes and tidal waves ravaged the area of modern day Lebanon, destroying many coastal cities. Today, some Beirut retirees still refer to the City's middle-aged population as the "post earthquake kids," in reference to the devastating quake that struck the city in March of 1956, killing many of the City's children.

"I was recently reading about insurance coverage in Turkey and apparently there were a large number of institutions that were not covered for earthquakes," comments William Salem, vice president of marketing for Societe Nationale des Assurances (SNA) in Lebanon, which recently merged with the AGF—Allienz group.

"Many of these institutions were totally destroyed and, without insurance, have no means of rebuilding. The use of natural hazard maps can help a great deal in developing information to provide adequate earthquake insurance coverage here in Lebanon."

For more information, please contact Andreas Siebert, Munich Reinsurance Company (e-mail: asiebertmunichre.com).

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