Earthquakes in Switzerland – the greatest natural hazard

Bern, 04.09.2006 - Switzerland is the host nation for the first pan-European Conference on Earthquake Engineering and Seismology. Being held in Geneva from 3 till 8 September 2006, this conference is bringing together over 1000 scientists and engineers to exchange their experience and ideas on the subject. In his opening address, Federal Council President Moritz Leuenberger will underline the importance Switzerland needs to place on the natural hazard of earthquakes. Despite the relative risk of serious seismic events in this country being classed as moderate to medium, a serious earthquake could occur in Switzerland. In this event, the anticipated damage lies between 7 and 60 billion francs.

Structures in earthquake-endangered areas need to be built safely, so an exchange of expertise between seismologists and building engineers is indispensable. For this purpose the "First European Conference on Earthquake Engineering and Seismology“ is being held in Geneva. More than 1000 participants from Europe and non-European countries are expected to attend. The conference is being organised by the Swiss Seismological Service SED of the Zurich Institute of Technology ETH, the Swiss Society for Earthquake Engineering and Structural Dynamics SGEB, and the Federal Office for Environment FOEN.

In his opening address, Federal President Moritz Leuenberger called for the expansion of provisions for seismic safety: “Reason tells us that we cannot prevent an earthquake, but we can limit its effect.“ Various protective measures are foreseeable – such as regulations for seismically safe construction and the introduction of an insurance system, similar to those which exist for other risks. ”A portion of the premiums collected could be used for seismic safety measures“, suggested Leuenberger. The Environment Minister called for the responsibility for seismic safety to be moved to a central federal authority.

90 percent of buildings are insufficiently protected

The high damage potential makes earthquakes in Switzerland the greatest natural hazard. Around 90 percent of the structures in Switzerland are not subject to seismic safety regulations at all, or, if they are, these are out-of-date, resulting in many buildings lacking sufficient insurance cover. Swiss reinsurers calculate that in the event of a quake of magnitude 6 on the Richter Scale, claims for damages could reach around seven billion francs, and for a quake approaching magnitude seven, this rises to around 60 billion.

On a world scale, the danger from earthquakes in Switzerland is categorised as moderate to medium. As the map from the Swiss Seismological Service SED, of the ETH Institute of Technology Zurich, shows (see SED Factsheet 1), the highest risk of earthquake is in Valais, the Basel Region, central Switzerland, Engadine and St. Galler Rheintal. As a guide, experts suggest that earthquakes of magnitude five on the Richter Scale are possible in Switzerland in the coming decade, while a magnitude six event may occur once within the next 100 years. For comparison: the earthquake of 1356 in Basel registered an estimated magnitude of 6.9.

The Best Response is Earthquake-Proof Construction

The Swiss people are nevertheless not defenceless in the face of earthquakes – provided the relevant SIA standards are applied: the best prevention of disaster lies in earthquake-proof construction techniques. When architects and structural engineers of a building work together from the beginning, the extra expense of integrating seismic structural measures usually amounts to at most one percent of the total construction costs. In the design, special attention should be given to ensuring that the load-bearing structure is strong, contiguous and even. In particular, the groundfloor should be designed to be stable (sufficient load-bearing reinforced concrete walls) and features such as drop ceilings should be attached securely enough to survive a seismic event.

The Federal Government promotes earthquake-proof federal buildings

In Switzerland structural seismic safety is regulated by the individual cantons. Efforts to anchor the protection against the natural hazard of earthquakes in the National Constitution have so far been ineffective. The Federal Council decided in 2000 to improve earthquake safety in federal buildings, and for this purpose what is now the Federal Office for Environment created a Coordinating Office for Seismic Safety (see Factsheet "Federal Seismic Safety“). So far, over 300 federal buildings and 3000 national road network bridges have been inspected and inventoried. By 2008 a further 500 federal buildings will be assessed for their seismic safety, and where necessary reinforced. The most prominent example is the Federal Parliament Building in Bern, which is being reinforced as part of its current renovation.

Address for enquiries

Andreas Götz, vice-director Federal Office for Environment FOEN, 079 475 64 78
Prof. Domenico Giardini, ETH Institute of Technology, Zurich, director of the Swiss Seismological Service, 044 632 42 44 (Media Desk ETH Institute of
Technology, Zurich)
Prof. Alessandro Dazio, ETH Institute of Technology, Zurich, Chairman of the Swiss Society for Earthquake Engineering and Structural Dynamics SGEB, 044 632 42 44 (Media Desk ETH Institute of Technology, Zurich)
Olivier Lateltin, Coordinating Office for Seismic Safety, FOEN, 079 475 64 80