Nov 24, 2004 - to the Salò case (Brescia province, Italy). Scira Menoni DIAP-Politecnico di Milano. Abstract. In the last years the âdisasterâ scientific community ...
Seismic vulnerability assessment: from individual buildings to the urban fabric and beyond. Applications to the Salò case (Brescia province, Italy). Scira Menoni DIAP-Politecnico di Milano Abstract In the last years the “disaster” scientific community has increasingly recognized the relevance of vulnerability and related concepts (resilience, coping capacity, adaptation) in managing natural risks. The limitation of structural measures taken with the aim of reducing the hazard severity and/or frequency has come to evidence. Those are still important; yet other measures able to reduce exposure and vulnerability are recognized as increasingly necessary. Seismic engineers have been dealing with physical vulnerability of structures since long time, as clearly nothing can be really done to mitigate earthquakes as phenomena. Not only new constructions were covered by analysis and care, but also the large built stock, including historic heritage. Seismic engineers have achieved significant advancement in vulnerability assessment. However, several recent events in Italy and elsewhere have dramatically shown that structural resistance is one component of the overall seismic response of complex systems like cities, but not the only one. Urban and spatial planning decisions should embed concerns regarding amplification zones, potential induced effects triggered by an earthquake (like tsunami or landslides), cascading effects among interconnected systems. This has been done only to a very limited extent until now. Among the reasons is the lack of tools for actually addressing the multiple vulnerability facets that must be looked at for such a comprehensive mitigation effort. In the article, the results of a recently concluded European funded research project (Ensure) are presented; an application of the tool and methodology developed during the project has been carried out on the case of the Salò municipality in the province of Brescia, Northern Italy. Keywords: seismic vulnerability; systemic approach; vulnerability and resilience
1.
Introduction
In this paper an application of a European funded project Ensure (Enhancing resilience of communities and territories facing natural and na-tech hazards), concluded in June 2011 will be discussed. The project aimed at developing a model for assessing physical, systemic, social and economic vulnerabilities to multiple stresses. The concept of vulnerability as a key factor in the risk function has emerged slowly in the scientific community studying natural hazards, that has privileged for long methods based on hazard assessment and aimed at providing structural mitigation measures. Seismic engineering has represented a sort of exception, as it has been understood rather early that given the impossibility to reduce/mitigate the threat, the only possible defense is to lower existing vulnerabilities in exposed structures. Since the Seventies and the Eighties seismic engineers have been developing methodologies for assessing buildings and infrastructures vulnerability; Italy has given a significant contribution, also because a strong cultural incentive exists to protect the traditional built heritage, which goes beyond individual selected monuments and comprises historic centres, that mark the collective identity of entire communities [Benedetti e Petrini, 1984]; [Angeletti et al., 1988]; [Guagenti e Petrini, 1989]).
It must be recognized, though, that for long time seismic vulnerability methods have been developed and applied for ordinary residential buildings, leaving out several sectors that have been scarcely investigated until recently. Some time was needed also to fully appraise the relevance and the full meaning of the vulnerability concept, and mark its difference with respect to other terms, like damage and/or exposure [Petrini, 1996]. Even for ordinary buildings research was required to move from an initial understanding of the factors that make a structure resist or collapse under the seismic stress to the development of a comprehensive method, comprising indicators, criteria for assessment and for assigning each building to a given vulnerability class. Still, several other aspects or building types remained excluded from analysis. At first attention had to be devoted to the scale of assessment. In cases where large areas and regions have to be analysed, a rapid assessment methodology, using “poor” data, like statistical or census surveys, must be applied [Bernardini, 2000]. It is rather obvious that when the assessment of the built stock of a nation or a large region must be evaluated, a one by one assessment is not feasible. Furthermore, for decision makers at the national or regional level, even a rough assessment may be useful and informative in guiding toward funding and prioritization. A second step forward in the widening of the methodology required to extend the analysis to other territorial objects, that are important in defining the response capacity to an earthquake. Different studies have tackled lifelines, schools, hospitals, churches. Those are all cases where significant problems arise because of the building type and content characteristics, for which standardized approaches are not always possible, or possible with caution and care [Doglioni et al., 1994];[ Lagomarsino et al., 1997]. As a third advancement, studies have been conducted to assess the behavior of built complexes, particularly in historic centres. As shown in many instances of historic centres affected by earthquake, the seismic response of a built complex may be significantly different from the behavior of the sum of the individual parts which comprise it [Grimaz, 1993]. Doubtless, the evolution of the vulnerability concept and vulnerability studies in seismic engineering is relevant, especially in comparison to other fields of natural hazards [Petrini, 1996]. The methodological path followed in over thirty years by seismic engineers can well be taken as a reference for scholars in other fields of natural hazards. Such path includes the following steps: first post-impact in depth damage assessment is carried out to identify those weaknesses and fragilities that can be considered as the “causes” of the damage (revealed rather than provoked by the ground shaking). Clearly what makes a building prone to damage in case of earthquake or flood is different, yet the methodology to follow is the same. Once the main parameters eliciting such fragilities are identified, a matrix to assess the vulnerability of any building to future events can be created. A correlation between damage and magnitude (or any other measure of severity) has to be established, and different curves will represent a variety of vulnerability conditions. Moving from one curve to another, the expected level of damage for the same magnitude (or severity level) is represented. This way, the damage is related to the event intensity or magnitude on the one hand (but here no mitigation intervention can be taken) and to the vulnerability level on the other (here is where mitigation intervention can be decided). What has been described above is a rather general theoretical framework that has been adopted by the Ensure project to extend it to assess buildings vulnerability to other hazards (forest fires, landslides, volcanic eruptions, floods). Besides, the Ensure project aimed at exploring the vulnerability concept more in depth and at large, and to develop a comprehensive framework accommodating also other vulnerability facets: systemic, social, and
economical. In this regard, the project introduces innovation also in the seismic risk domain, as those facets have been scarcely considered in traditional seismic engineering studies. In the following sections, the comprehensive framework developed in Ensure is presented; then an application to the area of Salò (a small municipality on the Garda lake in the province of Brescia, Lombardia Region, Italy) is discussed. This area has been chosen because an extensive prior research effort has been carried out in previous studies, thus providing the data needed for the full application of the proposed methodology (see [Regione Lombardia, 1996]; [Boni et al., 2002];[ Petrini et al. 2000]; [Menoni et al, 2007]; [Pergalani and Petrini, 2004]).
2. A conceptual model to assess the multiple facets of vulnerability. The concept of vulnerability has gained significant interest also in the other fields of natural hazard studies. This is evident by comparing quantitatively the number of articles produced in the last decade to those produced in the previous forty years or by considering the growing number of initiatives at the international level. The European Commission has devoted an entire research track to vulnerability in the 7 FP; the United Nations promoted a “resilient cities” campaign to make cities aware of their vulnerabilities and to make them better prepared to face emergencies and disasters. A certain convergence has been witnessed also between more technical studies on vulnerability and those oriented at understanding the social, economical, and human side of vulnerability. Those studies have used different and sometimes even divergent methods, expressions, terms. Nevertheless in the last ten years a significant effort has been made so as to harmonise, provide more structured and comprehensive methods reconciling rather than separating different perspectives and approaches to vulnerability. One of the first attempts to provide a multi-hazard, multi-perspective approach to the vulnerability assessment of communities exposed to natural hazards is represented by a study conducted in Cairns, Australia (Granger et al., 1999). At an international level, the Pressure-Response model has been proposed also for natural hazards (PressureRelease, see [Wisner et al., 2004]). In such method, poverty, lack of access to resources and services, overexploitation of natural resources limit communities’ capacity to respond to an external stress provoked by a “natural” extreme. International agencies such as the UN-ISDR (United Nations Strategy for Disaster Risk Reduction) and UNDP (United Nations Development Programme) have adopted such model in their evaluation of vulnerability and disaster risk condition of countries around the world. Sometimes such assessments and studies tend to be too ideological, equaling vulnerability to poverty, underdevelopment to vulnerability, without getting to the detailed understanding of why and what specifically makes a given poor community more fragile and exposed than a richer one. Stretching those positions to an extreme, it may seem that development means automatically vulnerability reduction; though we know that this is not true and that vulnerability depends significantly on the type of development which is foreseen. Some authors have raised the issue of uncritical judgments on vulnerability based on stereotypes and given for granted assumptions, showing how even well grounded indexes such as GDP, poverty index, age index, may be conducive to wrong assessments if they are not correctly put into a context [Buckle, 2000; Handmer, 2003].
More recent frameworks have been proposed for example by Roberts et al. [2009] and Longstaff et al. [2010], which attempt not only to provide an accommodation for different vulnerability facets but also to connect them to a more general risk evaluation. The conceptual framework that has been developed in Ensure is related to those that have been described, either in terms of the general idea of providing a framework before getting to the actual assessment or in terms of individual indicators or aspects to be considered. The proposed framework responds to four main objectives: - First it aims at operationalising theoretical definitions of vulnerability and resilience, at providing public administrations and agencies in charge of risk prevention with a tool they can use. - Second it responds the need to structure and synthesize aspects that are recognized as crucial for vulnerability and resilience assessment: the relevance of spatial scales, as different vulnerability facets emerge and/or interact at different levels, and the importance of temporal dynamics. A community’s response capacity to an extreme event is not constant over time: on the one hand it is the result of a historic process, including administrative, planning and programming choices (or lack of); furthermore, such capacity change across the disaster phases. - Third, the framework is useful in making explicit the selection made by the project among the many terms addressing coping capacity, resilience, vulnerability, adaptation, etc. Those terms have been debated for long among “disaster” scholars, but they have certainly gained relevance in the climate change community. - Finally, the framework constitutes a reference for positioning the various parameters that have been proposed for practical assessment purposes and which will be discussed below in the next sections.
2.1.
Description of the framework to assess vulnerability and resilience to natural hazards In this section the framework guiding in the assessment of vulnerability and resilience to a variety of natural hazards will be presented. The framework is shown in figure 1.
As it can be seen in the figure, the framework is deployed in a spatio-temporal plane, where the spatial scales for the assessment of hazards and vulnerability are represented in the ‘y’ axe, and the temporal scales in the ‘x’ one. First the reason for having different spatial and temporal scales for hazard and vulnerability must be explained. As for the spatial scale, what can be considered as a “local” threat, a local “extreme” may in fact produce consequences on a much larger area, sometimes even regional, national or even global. A typical example is represented by the Eyjafjallajökull eruption in 2010: a rather local explosion, that has not provoked significant physical damage in the area affected nevertheless several economic sectors at a global scale. Regarding the scale at which different vulnerability facets must be assessed, the physical is typically relevant at the local scale, but its root causes have to be looked for at a national scale, at which buildings codes and other regulations are decided. Sometimes such norms are even decided at larger scales than national, as for the case of the Eurocode in Europe. Other relevant root causes of physical vulnerability may be found in institutional, social, and economic weaknesses, which hamper the implementation of norms, even when the latter exist and are of good quality.
scale (of hazards)
Scale (at which vulnerabilities are considered)
Regional Multi -site
Macro
Resilience:
(regional, national, global)
meso
Mitigation capacity
Systemic vulnerability: Physical vulnerability:
local micro
Capacity to transform losses into opportunities
vulnerability to losses
vulnerability to stress
time impact Premonitory signs
impact
emergency Impact duration
recovery Repeated impact
recostruction Hazard time scale
Fig. 1. Conceptual framework to assess vulnerability and resilience
Often, technical experts assume that once state-of-the art regulations are passed, at least the new or retrofitted buildings will be more resistant; unfortunately this is not necessarily the case, as lack of compliance, poor inspection capabilities, underdeveloped professional skills or scarce recognition of the relevance of safety issues in the building sector [Bosher et al., 2007] are all factors that will limit significantly the potentialities of the new norms. In a rather interesting article, Thiruppugazh [2007] recalled that the main cause of the large number of collapses consequent to the Gujarat earthquake in 2001 was the lack of enforcement of the good quality building codes that existed in the country. Builders and aspirant homeowners were mainly seeking gain on the one hand and affordable housing on the other, neglecting seismic risk. What seemed a “win-win” solution (low compliance, cheaper houses) turned into a tragedy when the earthquake revealed all the fragilities of those poorly built constructions. As for the temporal scale, since Haas et al. [1977] work and Geipel’s [1979] analysis of the Friuli earthquake, we are used to consider different disaster phases: pre-impact, impact, emergency, recovery, and reconstruction. The fact that those phases are part of a cycle is represented in the figure with the reverse dot arrow: it is well recognized in fact that the phases are connected to each other. What is made before the impact influences the latter but also the capacity to respond in the crises and recovery; decisions made during reconstruction will make the system more or less resilient to the next event impact. Some studies go even further, by suggesting that policies and strategies set in the pre-impact time will influence also the recovery and even the quality of reconstruction. In this respect, having a plan ready for the reconstruction in which preevent vulnerabilities are carefully addressed is key towards resiliency. In other words, vulnerability and resilience change over time and the factors that must be addressed in each
phase are different as well. Damages, direct and indirect, depend on pre-event decisions but are also provoked by wrong decisions during emergency and recovery. The proposed framework has been developed having in mind the fact that vulnerabilities and resilience are transformed and shaped over time by decisions (or lack of), by actions (or lack of) which are both of individuals and collective. Therefore, in assessing mitigation capacities the tools, knowledge, resources available and invested to lower vulnerabilities and manage risks have to be evaluated. At the impact, physical vulnerability gains relevance, as the natural extreme stresses the different elements by evidencing their intrinsic fragilities: weaknesses in the community, as the more aged or younger population may be less equipped to escape and rescue themselves; fragilities of infrastructures, critical facilities and the built environment at large. In the next phase, other forms of vulnerability emerge, that are labeled as “systemic”. With this term the propensity to systemic damage, that is to the second order damage due to the consequences triggered by the physical damage. An example of systemic vulnerability is provided by lifelines: the physical damage they suffer may be rather small in percentage, but the consequences may be spread over entire system and affect all sectors that depend on them (that is the majority; and the more developed the system the higher the interdependency). Finally, in assessing resilience in the reconstruction phase, one must look at social and human capital, as well as to financial and economical resources that may be made available for a positive outcome reconstruction, one in which pre-event vulnerabilities are lowered and a more sustainable urban development is achieved. As shown by Cutter et al. [2008] there is no agreement in the scientific communities working on climate change and disasters regarding definitions of concepts like vulnerability, resilience, adaptation, and the like. In the Ensure project, the following decision has been made regarding terms: vulnerability reflects fragility and propensity to physical direct and systemic indirect damage, whilst resilience relates more to the social and human capacities to mitigate risks before the impact and transform losses into opportunity for a more sustainable development or re-development during reconstruction. As said for the spatial scale, also the temporal one does not necessarily coincide for vulnerability and resilience analysis on the one side and hazard on the other. For example, in the case of earthquakes, one may experience severe aftershocks or seismic storms that challenge the capacity of affected system to react and recover positively: when recovery starts, a new event may bring back the system to another crisis. At this point we need to explain how the objective of providing an operational tool has been achieved. Each ellipsoid is translated into a set of matrices, in which parameters for vulnerability and resilience assessment have been identified, as well as criteria and key for measurement and assessment. Similarly to what has been done for the assessment of seismic buildings scores are assigned to each vulnerability or resilience parameter so that at the end a sum provides a
synthetic description of the condition of the four systems under analysis. The weight represents the relevance of each parameter in the overall evaluation. A harsh discussion was held during the project meetings to decide if it made sense or not to move from a totally qualitative toward a scoring system. At the end in some of the case studies the scoring system was introduced, in others not. Here the rules adopted elsewhere in the Ensure project has been adopted: 5 represents the maximum level of resilience and 1 the lowest; 5 represents the smallest vulnerability and 1 the highest. This way 5 corresponds always to a “positive” outcome of the assessment, 1 to a “negative” judgement. In other case studies also a weight system was adopted to rank the relative importance of parameters in the overall assessment. For the case of Salò all parameters are considered of equal relevance. Each of the four matrices, and their sub-matrices, are organised by columns. In order from left to right the columns identify the a) system being assessed (e.g. natural hazards, critical infrastructures or people/individuals) and b) components (e.g. critical infrastructure) c) the aspect which is often addressed in the form of a question (e.g. what are the actors which make critical infrastructures vulnerable?) Next, d) is the parameter (i.e. indicator) chosen for the aspect followed by e) the criteria for parameter assessment i.e. how the parameters may be measured and assessed using what tools, such as maps, and then f) descriptors (e.g. presence or absence, categories, quantitative measures). In the final column, the vulnerability assessment outcome of the application of each parameter is recorded. The four systems that are considered in each matrix are:
-
-
Natural environment. Until recently the vulnerability of the natural environment was not considered, as the stressor is considered as part of the natural system. Nevertheless this is not true for all hazards: in the case of contaminated floods or forest fires it makes sense to consider the fragility and capacity to recover of potentially affected ecosystems. On the other end, parameters related to this section of the matrices relates to the level of understanding, information of the natural environment associated to the main hazard, including potential enchained effects, like tsunami and landslides triggered by an earthquake. Built environment, that comprises mainly public and private buildings an facilities. Critical infrastructures and production sites: those clearly are part of the built environment, but, because of their relevance they have been treated separately. Socio-economic systems, intended as individuals, institutions, and organizations.
A set of four matrices, related to the mitigation capacity, the physical vulnerability, the systemic, and the resilience during recovery and reconstruction have to be compiled for each hazard. In fact a distinct set of four matrices have been prepared for all the hazards considered in the Ensure project: besides earthquake, matrices for assessing vulnerability and resilience to floods, forest fires, landslides, volcanic eruptions, and drought have been developed.
3.
Application of the Ensure methdology to the case of the Salò municipality (Italy)
The Ensure model has been applied to the case of the Salò municipality, in the Brescia Province, Lombardia Region, Italy. As for the time scale, the impact has been made corresponding to an actual event, the earthquake that hit the area on the 24th November 2004. 3.1.
Resilience as pre-event mitigation capacity
In the first matrix shown in table 1., the mitigation capacity before the 2004 event is assessed. As for the available knowledge regarding the hazard, the municipality was classified as seismic in the second “category” as defined by the decree “D.M. 5 March 1984”. With the new n. 3274 Ordinance of the Presidency of Ministries Council in 2003, “Primi elementi in materia di criteri generali per la classificazione sismica del territorio nazionale e normative tecniche per le costruzioni in zona sismica”, the muncipality has been re-classified in the newly defined “second zone”. At the date of the earthquake, a seismic zoning of areas potentially subject to amplification effects of ground shaking was not available. Such zoning has been made compulsory by a regional law in 41/1997 to support local urban planning. The obligation was even reinforced in 2005, in article 57/1 of the new Urban Planning law of the Lombardia region (see the guidelines to the “Criteri ed indirizzi per la definizione della componente geologica, idrogeologica e sismica del Piano di Governo del Territorio, in attuazione dell’art. 57, comma 1, della l.r. 11 marzo 2005, n. 12”). As for induced instability, a map and a report representing potential rock falls and landslides as a consequence of expected level of ground shaking were available in the area. In particular the landslides is active in the part directly menacing the historic centre of Salò. The publication where such studies were made available dates back to 2006 [Menoni, 2006], nevertheless the geological reports were available since years before 2004. It must be also highlighted that, according to more recent geological surveys, the dimension and extension of the landslide should be revised and are probably less hazardous than initially considered. As for the built environment, physical vulnerability assessment of ordinary buildings were available for all seismic municipalities in the Lombardia region since the year 1996 [Regione Lombardia, 1996]. In the years between 1999 and 2001, the Regional administration has conducted two studies to assess the vulnerability of lifelines to earthquakes [Petrini et al., 2000]; [Boni et al., 2002]. In order to conduct the study, a methodological framework has been developed [Menoni et al., 2007] and an extensive effort to collect relevant data was carried out. It can be said in this regard that the amount of studies existing at the date of the earthquake was considerable, especially in comparison to other areas in Italy. Nevertheless those studies have not actually been used in the development of neither master plans nor emergency plans. Coherently, a high score (4 and 5) has been assigned to the parameters defining the existence and the quality of vulnerability assessment, whilst a low score (1 and 2) is assigned to all the parameters related to the level of integration of such assessments in plans and risk mitigation programs. As for the social and the economic systems, the level of awareness of seismic risk was rather low at the time of the last earthquake, and the memory of the large seismic event at the beginning of the last century (1901) had faded away, despite of the fact that the walk along the lake was built as part of the 1901 reconstruction project. System Components
Aspects
Natural Environment
Assessment of present hazard
Natural hazard
Assessment of induced hazard
Parameters Seismic hazard maps and seismic boundary areas
Map of the amplification areas
Hazard maps that include the induced hazard (landslides)
Scale and evaluation criteria
Evaluation tools
Score (5=max res.; 1=low) Application to the Salò case
2 Scale: local and provincial; binary; quality yes/no; expert judgment of the produced maps
Binary
Seismic network availability Scale: local e provincial;
1
yes/no; the appropriate scale
4
yes/no
5
The towns of the Garda lake in the Brescia Province were classified in 2 seismic category according to the national classification PCM 3274 of 20/3/2003. Possible local amplification was not available on zoning maps There were several studies available at different scales on seismicity related landslide hazard scenarios The main event was recorded by a station of National Motion
Table 1. Application of the first matrix to assess resilience as mitigation capacity Summing up, even though the area was known and certified as a seismic zone, and even though vulnerability and risk assessment were available at the time of the 2004 earthquake, covering basically all main parameters
required by the Ensure methodology, some weaknesses can be observed. On the one hand studies concerning amplification were not available, on the other existing risk and vulnerability assessments were scarcely integrated into urban and emergency plans. 3.2.
The physical vulnerability at the time of the earthquake 2004.
Moving to the second matrix, in table 2, the already mentioned vulnerability studies assigned a medium level of vulnerability to the municipality, given the large reinforced concrete stock. The 2004 low level of physical damage reinforces such assessment (corresponding to a 4 score). According to data furnished by the at the time director of the local office of the Lombardia Regional Government, Carlo Giacomelli 1, only the 10% of the 7000 inspected buildings was not usable after the earhtquake. 90% of inspected buildings were private, with the remaining 10% consisting of 267 public buildings and 375 religious (with a peak of 18% of damaged monuments and religious buildings; see also Casali and Ibsen, 2009). In any case the number of severely affected constructions is low. The data reveal the higher vulnerability of the cultural heritage (to which a 3 score has been assigned); in this regard, the already mentioned study on historic centres in seismic areas [Menoni, 2006] had produced an evaluation of buildings and built complexes in Salò. A specific matrix had been developed to assess the vulnerability of built complexes, a situation which is very common in historic centres in general and in Italy in particular.
Figura 2. Maps representing buildings vulnerability according to the (1996) study and the vulenrability of built complexes reported in [Menoni, 2006]. The earthquakes in Friuli, 1976 and Parma, 1983 had shown that not only built complexes do not behave as the sum of the individual buildings taken separately, but that differential maintenance practices and usages which imply change in structures have a relevant impact on the entire complex as a whole. As shown in figure 2., the Municipal building was assigned a high vulnerability score and was in fact severely damaged by the 2004 earthquake. Damage to people was limited, also thank to the lucky circumstance that made occupants of a building which was partially destroyed by a rock fall to survive.
Built environment
Natural system
System Components
Natural ecosystem
Aspects
Parameters
Criteria for evaluation
Evaluation tools
Fragility of the system to seismic risk
Landslides induced by earthquakes
Relevance of the affected areas
number / extension of affected areas
Score (5=low vuln.; 1=high) Application to the Salò case
1
In Clibbio, along the Chiese river, several rockfalls occurred,destroying also two houses, detached blocks of dolomites up to 75 mc
Dati forniti nel corso di un seminarioassessments “Seismicat the emergency management” tenutosi presso la4sedetheditown Lecco town Methodology GNDT high/medium/low of Salo,del showing a medium/low scale vulnerability condition Exposuredi andMilano Factors increase the2011. Politecnico il 6thatmaggio Studies conducted in the historical
1
Seismic vulnerability
vulnerability of the built environment
vulnerability of the built environment to earthquakes
Maps and assessments are available for
Vulnerability assessment of Specific parameters, with the historical center and particular emphasis on the high/medium/low single monuments construction clusters
electricity
high/medium/low
3
5
center of Salò provided a medium vulnerability score in the historical centre, with some elements of high vulnerability, such as the Town Hall Low, also with respect to the specific assessment that was conducted for the
Table 2. Physical vulnerability assessment
3.3. Evaluation of systemic vulnerability as evidenced in the 2004 emergency The already quoted studies conducted to assess the seismic vulnerability of lifelines permitted to rank their systemic vulnerability as medium and medium-low (corresponding to an overall score of 4 for some of the paramters in table 3). The Garda area was nevertheless showing higher levels of systemic vulnerability with repsect to the rest of the Province, as a consequence of the area morphology, implying poor accessibility at least by road. After the 2004 earthquake no particular acessibility problem was recorded, despite some rock falls limiting access to certain villages and collapsed debris in the historic centre. The institutional response of the civil protection was overall good, and after 45 days intervention plans for the most affected zones were already available for starting reconstruction. The most severe systemic consequences were due to the unusability of several schools and of the Municipality building. Classes of schools were re-assigned in other usable facilities and they worked according to a turnation timetable; services that were hosted in the municipality were relocated in other two buildings: public works, master plan offices were located within the Telecom premises, while the local emergency centre (COC) was setin the Auditorium Battisti. Therefore, the score attributed to the paramter related to public facilities in table 3 is ‘3’. The relocation of public facilities during emergencies is highly stressful for officials and staff; in the case of Salò the problem cans be considered as minor considering the relevance of functions that had to be moved. The l’Aquila earthquake in 2009 has shown instead what may be the significantly high systemic effects when a regional capital city, relevant at large scale for a number of services, is affected and public facilities destroyed or considered too dangerous to be used.
Natural nvironment
System Component
Natural ecosystems
Aspect
Aspect Parameters
Criteria for assessment
Fragility of ecosystems to potential secondary effects of hazard(s)
areas affected by landslides number and extent
Parameters values and/or categories
few/many; in remote areas/in crucial-central zones
Score (5=low vuln.; 1=high)
2
Application to the Salò case As shown by studies conducted before 2004, the area is subject to potential induced landslides, as all the coastline along the Gard lake is constituted by steep slopes. Nevertheless, in the 2004 event only one case of
Table 3. Systemic vulnerability assessment 3.4. Resilience and reconstruction
The discussion on the resilience matrix deserves perhaps a couple of words more. Undoubtedly, the 2004 5.2 on the Richter scale earthquake was rather moderate. The physical damage was limited. However, the limited severity of the shaking does not fully explain the high level of resilience evidenced in the reconstruction. The choice not to evacuate the almost 2000 homeless to temporary shelters was an illuminated one and permitted a rapid return to normalcy. Instead of ignoring the tendency of people to search for accommodation by relatives and families, it constituted one of the leverage of the post-event policy. On the other hand the civil protection took advantage of the low season, to use as much as possible the accommodations available in the area. Also the idea of the mayor to guarantee for renters to be hosted in vacant dwellings was a good one. Equally effective the strategy already adopted in the previous 1997 Umbria Marche earthquake to distinguish different classes of repair needs: a first one for which with a small amount of money (below 10.000 Euros) rapid repairs were possible and immediate return home was possible; a second one requiring more expenses as a consequence of a severe level of damage; and finally a third category for which an integrated reconstruction was required. Such “integrated reconstruction” was required in the city historic centre, so as to adjust the reconstruction project to the other safer buildings and to the characteristics of open spaces and monuments of the historic centre. Equally convenient the prioritization among different interventions, privileging public services, production sites, primary residencies with respect to secondary houses. As part of a resilient response two documents prepared after the 2004 earthquake can be mentioned: the emergency municipal plan on the one hand and the enforcement of the geological report in the newly adopted master plan (PGT adopted in 2008 and finally approved in 2009). As for the former document, it summarizes the main risks to which the municipality of Salò is exposed. The document provides all necessary information regarding the hazards, though in a form that is not so ready to be used during an emergency. As for many other contingency plan that the author was able to analyse, a clear distinction between hazard and risk description and activities to be carried out during a crisis is lacking. For example, the emergency plan reports the forms used to assess the vulnerability of lifelines that were developed for the Lombardia Region in 2001. Nevertheless those forms are not part of a structured framework and their use in the plan is neither clarified nor easy to understand. As for the urban plan (PGT), the geological report has to be part of the planning document according to the regional law LR 12/2005. Nevertheless, after a careful reading it can be seen how pieces of the geological report are introduced in the master plan document without any significant attempt to fully acknowledge the implications of technical considerations regarding seismic hazard. Only partially different is the case of the hydrogeological risk, because in the case of the risk management plan for hydrogeological risks (PAI) already specifies some urban planning indications (see article 8.5). The urban plan reflects a more general practice according to which geological and hydrogeological criticalities are just presented because a law obliges to do so, but are not fully integrated into the planning process or the planning document. Hazards are translated into taking or limitation to development, without any attempt to make them part of a sustainability practice. For example, article 11 refers to the possibility of raising the roof to create further habitable space: no mention is made to the potential vulnerabilities that may be introduced in an otherwise seismic resistant building if no care is taken. The lack of true integration between risk assessment and urban and spatial planning is a common problem to many European countries, as was demonstrated in a former European funded research, Armonia (Applied multi Risk Mapping of Natural Hazards for Impact Assessment). This project aimed at providing on the one hand the state of art in the
relationship between risk mitigation and land use planning and on the other to create a decision support tool to guide planners in their activities in hazardous zones. The results of the Armonia project presented a situation in Europe where risks are treated in a rather sectorial fashion [Fleischhauer et al., 2006];[ Galderisi and Menoni, 2007], and a fragmented approach is followed to address individual hazards, even in cases where they are menacing the same areas, as is the case of the Salò municipality. The fragmentation is visible in the Salò master plan, where the limitations due to the hydrogoleogical risk management plan are considered separately from the feasibility classes reported in the geological report, whilst it is clear that the latter are taking into consideration the former. Furthermore as the Fleischhauer’ et al. book shows, risk mitigation is a separated issue, is not considered in the ordinary planning process. The geological report is useful in identifying those areas that are particularly critical and where development should not take place; it also provides fundamental information regarding location and severity of different hazards. Nevertheless it is not a suitable tool for making planning decisions, as it tackles mainly the hazard component of the risk function. The Armonia project proposed a guiding framework that should help planners in recognizing also exposure and vulnerability so as to suggest where and which kind of development may take place, and in deciding the transformation of already urbanized zones. In fact vulnerability assessment is crucial not only for new development but mostly for urban renewal and restoration. Similarly important the social and economic vulnerabilities as they can influence significantly the type of uses in buildings which in turn may induce structural changes that may cut the structural resistance not only under dynamic stress but also in normal static conditions. In the approved master plan (PGT) of Salò there is no mention to vulnerability studies or concerns regarding the vulnerability of the historic centres or of infrastructures. Therefore vulnerability assessments are not of guidance in deciding the best zoning, the location of public facilities and/or infrastructures, or types of uses that can be permitted in different zones and in different buildings taking into account also the type of spaces (and consequently of structures) that are needed for such uses. In summary, the territorial, social, and economic system of Salò has shown a high degree of resilience during the emergency and in the “physical” reconstruction. All parameters of social resilience are scored rather high as it can be seen in the matrix (table 4.), as the institutional response capacity, income, and availability of public funding for quick recovery were all at high levels. The administrative system has also responded in a positive way to the deficiencies that could be seen before the event: in fact, after the year 2004 new master and emergency plans have been prepared. Nevertheless, at a more careful look, both the latter documents may be improved, so as to better integrate the rather extensive knowledge regarding exposure and vulnerabilities that exist in the area. This is the reason why all the parameters that refer to the existence of a long vision that includes risk prevention as one of the planning criteria are ranked low (3) in the fourth matrix.
System
Component
Aspect
Aspect Parameters
Criteria for assessment
nment
Temporary transferability of facilities relevant for the binary; type of relocation settlement/city community life and economy
Parameters values and/or categories
yes/no; temporary/permanent
Score (5=max res.; 1=low) Application to the Salò case The Salò hospital was definetly closed, even though it was already in a process of closure ; the municipality was reopened in 2006, thanks to the reconstruction works partially financed 5 with the insurance coverage the public facility had against natural hazards; at the date of 2009 69% of public buildings were reopened (in particular schools)
Existance of plans for reconstruction in case of severe destruction scenarios
binary
yes/no
3
Reconstruction plans consider lessons learnt from earthquake (including amplification zones)
binary and quality
yes/no; seismic zonation map made available for reconstruction/not available
4
There was no plan; however the limited damage and the fast and positive decision making process permitted a fast and satisfactory recovery Probably a reconstruction plan was not needed in this case; the model of reconstruction that was adopted derived from the Umbria M arche quite successful experience.
Table 4. Post-impact resilience evaluation
Conclusions The Armonia project developed guidelines for urban and spatial planners that included besides hazard parameters also exposure and vulnerability criteria to decide zoning and location of services and facilities. The Ensure project, some years later, developed further the definition of vulnerability and resilience, providing an operational tool comprising parameters and criteria for their assessment. Clearly they have not solved all the theoretical and operational issues that emerge in the activity of planning areas exposed to natural hazards. The two projects have tackled only to a limited extent the issue of how to up- and down scale exposure and vulnerability assessments. The results obtained in different case studies, such as Salò, require further refinement. Such results are nevertheless relevant for two main reasons. On the one hand such applications highlight gaps in current knowledge and data. One important gap relates to the lack of reliable damage and loss data gathered in the aftermath of disasters. In the future we wish to find correlation between for example physical and systemic damage, as has been done between acceleration and damage with fragility curves. In this respect though our understanding of indirect, induced, and secondary damage is still very limited and insufficient. A more complete database of damages would constituted an important support for more informed reconstruction decisions, as it would permit a better prioritization among sectors, social groups more in need of scarce resources. Resources that are not only financial but also related to the human capital (the professional expertise needed during reconstruction). A better damage and loss reporting system would also facilitate the identification of better criteria and keys for assessing the different types of vulnerability that have been described in the previous paragraphs. Reports available on the Salò 2004 earthquake are in this respect still poor, as their focus is too strictly on hazard and physical vulnerability assessments. Other relevant information on indirect effects on economy and service provision are still documented in an anedoctical way; contributions like the relevant book of Casali and Ibsen [2009] respond to other needs than scientific investigation. They are aimed at providing a historical and even emotional perspective on the earthquake and its consequences on the affected community. We may well say that there would be the need to produce more scientific studies on the unfortunately many disasters which periodically affect Italy. If compared to other cases like the US or Japan, the disparity in the number and quality of studies developed after calamities is really striking. On the other hand, the Ensure methodology has permitted to structure such information, often in anedoctical form, so as to constitute a reference to be consulted in the future, to assess to what extent different types of vulnerabilities have been managed in the Salò area and to what extent resilience has increased (or decreased). This not necessarily considering only earthquake as the potential threat. One of the main advantages of such a methodology is the possibility to track over time the evolution of a territorial, social, and economic system as far as its vulnerabilities and resilience are concerned. Acknowledgments The help of Guido Minucci in getting the data and of Fabio Corgiat in producing the maps that are provided in the article is acknowledged
