Seismically Induced Hazards in Balzers, Liechtenstein: Why Ancient Balzers was Safer

Dr. Maria E. Brunhart-LupoDr. John Lupo

Mr. Werner Brunhart

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Dörrbecker, 2013

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Balzers, Liechtenstein

• Town in southwestern Liechtenstein• Area inhabited since the Hallstatt culture – Early

Iron Age• Town has been officially recognized since the early

800s• The castle, Gutenberg, has been the center of

town since the early to mid 1200s• Total area of historic town was ~ 7 sq miles• Total area of modern town is 7.6 sq miles

Seismic History

• Area is noted as seismically active for all of human history

• No record kept for Balzers, but kept for the Swiss side of the Rhine Valley

• Record shows earthquakes and associated hazards are known for the area from Roman times to modern

• Average is two earthquakes a day, usually under M2.0

http://www.seismo.ethz.ch/eq_swiss/Erdbeben_1975-2011.png?hires

Location of historic and modern Balzers

http://www.seismo.ethz.ch/eq_swiss/Erdbeben_1975-2011.png?hires

Seismic Hazards

http://www.seismo.ethz.ch/silva_ethz/ETH/erdw/seismo/seismo/research/groups/gbilder/hazard_map_475y_500px.png?hires

Seismic Hazards Affecting Balzers

• Landslides• Rockfall• Avalanches• Soil Liquefaction• Floods• Fires

Building Codes

• Within the past five years, particularly after a M5.4 hit the Rhine Valley in 2012, building codes have been rapidly updated

• All new buildings must be built to code, but older buildings are not subject to upgrade

• Need for updating of codes was raised due to the percentage of damage found in buildings constructed under ‘modern’ code

• Discrepancy lies in the relative lack of damage recorded in ‘historic’ structures

Damage Assessment

• 68% of modern buildings affected• Under 10% of ‘historic’ (1800s or earlier)

buildings affected• Modern building damage = cracking in walls and

foundations, broken glass, balcony detachments• ‘Historic’ building damage = settlement of

foundation footings, micro-cracking of exteriors

Construction Differences

• Modern codes versus older methods of construction

• Modern houses/resort housing versus farm houses

• Example of Gutenberg – 12th century style construction

Thank You

• Thank you for attending this presentation