The seismic events that hit the Umbria and Marche Regions in 1997-1998 represent recurrent crises in the seismic history of this area. These crises are mostly characterised by relatively moderate magnitudes; nevertheless in 1997-1998 they caused extensive damage in different towns, such as in the town of Sellano (Umbria Region). In the present paper, the geotechnical characteristics of the soil involved are examined in order to find the explanation for this phenomenon. The three most significant shocks which occurred during the 1997-1998 Umbria-Marche seismic sequence are chosen as “scenario” earthquakes. Then, on the basis of the site characterisation of the Sellano area, the soil response is analysed. For each different zone and for the input motions considered as “scenario” earthquakes the response spectra at the surface level are developed. Finally, the seismic, geotechnical hazard maps in terms of maximum amplification ratio and in terms of maximum horizontal acceleration at the soil surface are drawn-up
Gli eventi sismici che hanno colpito le regioni dell’Umbria e delle Marche nel 1997-1998 rappresentano delle crisi ricorrenti nella storia sismica di quest’area. Tali crisi sono caratterizzate essenzialmente da una magnitudo piuttosto moderata; tuttavia nel 1997-1998 hanno causato notevoli danni in diverse città, così come nella città di Sellano (Umbria). Nel presente articolo, la spiegazione di un tale fenomeno è ricercata nelle caratteristiche geotecniche del terreno coinvolto. I tre terremoti più significativi accorsi durante la sequenza sismica del 1997-1998 vengono scelti come terremoti “di scenario”. Quindi, sulla base della caratterizzazione geotecnica del territorio di Sellano viene valutata la risposta in supercie. Per ciascuna zona in cui è stato diviso il territorio di Sellano e per i summenzionati terremoti “di scenario” vengono calcolati gli spettri di risposta in superficie. Infine, vengono elaborate le mappe di pericolosità sismica-geotecnica in termini di massimo rapporto di amplificazione e di massima accelerazione orizzontale in superficie.
The ground motion grade - 3 microzonation of Sellano
P. CapilleriWriting – Original Draft Preparation
;
2001-01-01
Abstract
The seismic events that hit the Umbria and Marche Regions in 1997-1998 represent recurrent crises in the seismic history of this area. These crises are mostly characterised by relatively moderate magnitudes; nevertheless in 1997-1998 they caused extensive damage in different towns, such as in the town of Sellano (Umbria Region). In the present paper, the geotechnical characteristics of the soil involved are examined in order to find the explanation for this phenomenon. The three most significant shocks which occurred during the 1997-1998 Umbria-Marche seismic sequence are chosen as “scenario” earthquakes. Then, on the basis of the site characterisation of the Sellano area, the soil response is analysed. For each different zone and for the input motions considered as “scenario” earthquakes the response spectra at the surface level are developed. Finally, the seismic, geotechnical hazard maps in terms of maximum amplification ratio and in terms of maximum horizontal acceleration at the soil surface are drawn-upI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
