The road map for the seismic geotechnical vulnerability of the physical environment

Abstract

The increasing importance attributed to microzonation derives from the spatial variability of ground motion due to particular local conditions, from landslides and ground liquefaction noticed during recent earthquakes and from the awareness that many towns run a high risk because of the geotechnical characteristics of the foundations of structures. The Mediterranean area is characterised by a medium-high level of seismic risk, so earthquakes are a major cause of the destruction of monuments, residential and industrial buildings. Among the effects on the stability of the physical environment, landslides and liquefaction represent the most significant factors of vulnerability of the physical environment itself. Landslides are particularly relevant because they can deeply modify the physical environment and consequently they represent an aggravation factor for the vulnerability of buildings resting on a potentially landsliding slope. Microzonation of slope stability is then preliminary to the evaluation of the vulnerability of buildings. Vulnerability of the physical environment, related to the presence of cavities and to seismic induced landslides and liquefaction, has been analysed with special reference to the new modelling of such phenomena and to the application of the models to given areas. This paper deals with the vulnerability of the physical environment (landslides, liquefaction etc.), while the road map continues with the analysis of the vulnerability of monuments and buildings, with the aim of the estimation of the seismic resistance required to defend against seismic action given by the scenario earthquakes.

The local site response for upgrading the existing buildings against seismic hazard

“…Probably this fact is due to a non linear behaviour of soil that often occur [22], especially in presence of the strong accelerations of the 475 and 975 years of earthquake scenario. High values of soil amplification factors often occur in the city of Catania due to the characteristics of soils, both stratigraphic and topographic and also in other sites [23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The results of the site response analyses have been then used for the evaluation of the Dynamic Soil Structure Interaction (DSSI) [37,38] of the investigated building area, in terms of the maximum surface acceleration of the scenario earthquake chosen in the analyses.…”

Liquefaction potential evaluation at Catania Harbour (Italy)

“…Probably this fact is due to a non linear behaviour of soil that often occurs [16], especially in presence of the strong accelerations of the 975 and 2475 earthquake scenarios. High values of soil amplification factors often occur in the city of Catania due to the characteristics of soils, both stratigraphic and topographic [17][18][19][20]. The results of the site response analyses have been then used for the evaluation of liquefaction hazard of the investigated area, in terms of the maximum acceleration of the scenario earthquake chosen in the analyses.…”