RICERCA ITALIANA     

INDUCED SEISMIC HAZARD: ANALYSIS, MODELLING AND PREDICTIVE SCENARIOS OF EARTHQUAKE TRIGGERED LANDSLIDES

Università degli Studi di Roma "La Sapienza"

Abstract

The recent seismic events in South-East Asia demonstrated that "collateral damage"; may significantly exceed economic and social losses directly related to seismic shaking. Landslides rank among the main categories of effects due to the release of seismic energy. Seismically-induced landslide hazard and the presence of exposed elements and their vulnerability produce risks to be mitigated and managed. Therefore, a comprehensive approach to seismic hazard assessment in a given area requires a thorough study of the mechanisms that trigger or reactivate seismically induced landslides. Landslide bodies existing prior to seismic shaking may have not yet reached rupture conditions s.s.. Nonetheless, they may amplify seismic waves, alter seismic shaking and cause damage to the built heritage.
In view of the above, the prime objective of this research program is to develop scenarios of hazards and risks arising from mobilisation of landslides due to seismic stress and from major seismic amplification processes occurring inside the landslide mass.
To this end, studies will be conducted in geological and geomorphological settings that are typical of wide areas of the Apennine range. Recent earthquakes in these areas (e.g. Umbria-Marche, Molise and Sicilia) proved to have a considerable seismic potential in terms of frequency of occurrence and released energy.
In this framework, the contributions of the Research Units engaged in the project will focus on collection >>>

Principal Investigator

Gabriele SCARASCIA MUGNOZZA Università degli Studi di ROMA "La Sapienza"

Research Objectives

The main objective of the Research Program is the development of scenarios of hazards and risks arising from earthquake-induced landslide mobilisation, as well as from major phenomena of seismic amplification in existing landslide bodies.
Of considerable interest will be the study of earthquake-induced landslides on slopes that consist of texturally complex clays, in view of: their dissemination in wide areas of Italy; their involvement in more or less recent earthquakes (Irpinia 1980; Umbria-Marche, 1977; Molise, 2002; Sicilia, 2002); and presence of growing number of structures and infrastructures over the country and of new residential and industrial settlements.
To attain the objective, different investigation channels will be activated. These channels, although being part of a multi-disciplinary approach, will operate synchronously throughout the research activity.
Given the ultimate aim of this Research Program, each investigation channel will reach intermediate or partial goals; however, such goals will yield aspects of considerable interest and immediate benefits in terms of applications.
The partial goals, to be set upon research planning, will identify the milestones of the Research Program:
1. through specific laboratory investigations, assessment of monotonic and cyclical behaviour of lithotypes with dominantly clayey component and complex texture (e.g. “argille varicolori”) and, namely, of their stiffness and >>>

Timescale

24 months

National and international background

Seismically-induced landslides are historically documented for some ancient earthquakes, such as the 1783 Calabria event (Sarconi, 1784) and the 1786 Kanding-Luding (China) event (Dai et al., 2005), and for recent times there is a large database related to earthquake-induced landslides (Keefer, 1984; Rodriguez et al., 1999).
Landslides are one of the most damaging collateral hazards associated with earthquakes. In fact, damage from triggered landslides and other ground failures has sometimes exceeded damage directly related to strong shaking and fault rupture (Bird & Bommer, 2004). Seismically triggered landslides damage and destroy homes and other structures, block roads, sever pipelines and other utility lifelines, and cause damming stream drainages. Predicting where and in what shaking conditions earthquakes are likely to trigger landslides is a key element in regional seismic hazard assessment.
Local civil protection Agencies need to plan their emergency activities prior the disaster occurence, thus to be prepared to promptly bring assistance to the injured population. In this perspective, one of the most useful and effective tool is the formulation of scenarios, describing how the dangerous event manifest itself, its consequences in terms of damage and losses and the countermeasures to be undertaken to hamper such negative effects.
Unfortunately, though damage and ground motion scenarios have been largely developed in recent years (Fäh et al. >>>