Development of seismic damage scenarios in Lefkada old town (W. Greece): part I-vulnerability assessment of local constructions with the use of EMS-98

摘要

The present work constitutes the first part of a multi-parametric research for the representation of damage scenarios in Lefkada old town. The study area lies in the most seismically active zone of Greece and has suffered several devastating earthquakes. Most of its old buildings were built by local practices incorporating elements of earthquake resistance and have been designated as particular earthquake resistant constructions by the European Council Cultural Heritage Unit. The most recent earthquake of that occurred on 14 August 2003, located about 10 km from the town, caused moderate damage to its buildings and substantial geotechnical failures. Investigations on the coseismic effects yielded extensive literature information, which initially motivated our investigations. This paper deals with the empirical vulnerability assessment of the buildings in Lefkada old town based on basic structural characteristics such as the type and material of the structural system, the period of construction, the number of storeys, etc. Those characteristics, primarily available from the most recent available census were further exploited by an in-situ survey, during which all 1,420 buildings in the old town were inspected. Following, each building was indexed with an EMS-98 vulnerability class. Expert decisions on the damage scale due to the 14 August 2003 event were reassessed and converted into damage grades of EMS-98. The full data set was also analysed in ArcGIS producing detailed maps of the 14 August 2003 earthquake damage distribution by structural typology and vulnerability class in Lefkada old town.