Mapping earthquake hazard in a city is relatively familiar work: soil conditions, fault lines, ground motion, and building stock. But there is a question that these layers do not answer on their own:
Why does the same hazard turn into a far more severe social impact in some neighbourhoods, while other areas recover faster?
The answer is often hidden in the layers we do not “see” on a standard hazard map: income and employment conditions, age distribution, disability status, access to services, housing security, risk perception, and the capacity to act.
Istanbul Metropolitan Municipality’s main report on “Social Vulnerability” makes this point clearly: even though physical and economic losses are the most visible outcomes of disasters, we cannot complete the risk picture without understanding the social conditions that shape how communities prepare for, cope with, and recover from shocks.
In this article, I will explain social vulnerability in a practical way: what it means, why it matters, how it is mapped, and—most importantly—how it becomes action.
What is social vulnerability?
Social vulnerability refers to how a community’s pre-existing characteristics shape the extent of impact, its resilience under stress, and its capacity to recover. In the Istanbul context, this approach is explicitly discussed in relation to a potential “Istanbul Earthquake” scenario (URL-1).
A key point: social vulnerability does not simply mean poverty. Poverty can be a strong driver, but it is rarely the only one. For example:
- Concentration of elderly population (mobility constraints, care needs)
- Disability status and accessibility barriers
- Education and access to information
- Housing tenure and housing security
- Access to healthcare and social protection
- Risk perception and preparedness practices
- Social cohesion and neighborhood support networks
These factors can increase or reduce a disaster’s social impact. The purpose of the IMM report is to make these strengths and weaknesses visible and to assess levels of social vulnerability.
The Istanbul example: measuring “everyday life”
The IMM study brings social vulnerability down to the ground level instead of leaving it as an abstract concept. Based on address-based population data, it designed a broad survey framework and applied face-to-face interviews using CAPI (Computer-Assisted Personal Interviewing). The report states that the fieldwork relied on a sample exceeding 50,000 households, with surveys completed in tens of thousands of households and a high response rate.
This is important because such work can risk reducing lived realities into numbers. But when designed well, it can do the opposite: it connects statistics to real needs. The goal is not to “collect data,” but to relate data to life—so that vulnerable groups are visible and resources can be directed where they matter most.
What is a social vulnerability map used for?
These maps are not meant to produce a single “red zone.” They are meant to support decision-making.
1) Prioritization:
Where are preparedness programs, awareness campaigns, and training most urgent?
2) Targeted intervention:
Is the main driver income insecurity, low risk awareness, limited mobility, or poor access to services? Different causes can drive the same vulnerability score.
3) Investment and planning decisions:
How do we incorporate the social dimension into infrastructure investments and spatial planning? The IMM report positions its outputs as an evidence base for urban renewal, investments, spatial planning, and education/awareness efforts.
4) An equity lens:
Even if “averages” improve, who is left behind? Is recovery fair?
How does mapping work? (A conceptual recipe)
Social vulnerability mapping typically follows four steps:
1) Break vulnerability into components
The IMM approach organises social vulnerability into component groups and produces a composite score using weighting. Components include clusters such as demographics, socioeconomic conditions, risk perception/attitudes, and values; the results are then translated to district or neighbourhood scales.
2) Make the data “speak” in place
Survey data, administrative records, population information, and service-access layers are not useful as isolated lists. GIS brings them into a shared spatial logic, enables comparison, and reveals relationships across layers.
3) Produce a score—but don’t lose the “why”
Creating a single index is easy. The hard part is preserving the reasoning behind it. A key strength of the IMM report is that it highlights which components drive the vulnerability score, making it easier to design targeted actions rather than generic interventions.
4) Connect results to action
A good vulnerability map does not remain on a shelf. It is connected to risk reduction programs, communication plans, investment priorities, and local capacity-building. This is the core of risk-informed planning: risk knowledge becomes part of everyday planning decisions.
One clear finding: a strong socio-economic gradient
The IMM report states a very clear relationship: as socio-economic status increases, social vulnerability to disasters decreases.
This is not surprising, but it is strategically important. If you only talk about physical strengthening of buildings, risk may remain high in certain areas—because the problem is not only the building. It is also preparedness capacity, access, social protection, and the needs of vulnerable groups.
The report notes that, at the district level, Sancaktepe has the highest social vulnerability score, followed by Sultanbeyli, Sultangazi, Esenler, and Çekmeköy. Rankings should never be used as labels; the proper interpretation is to examine which component drives vulnerability in each district and shape action accordingly.
Two risks to avoid: labeling and false certainty
1) The risk of labelling
Saying “this neighbourhood is vulnerable” can easily turn into stigmatising language. Maps should not be used to “tag problem areas,” but to deliver services and reduce inequality in risk and recovery.
2) The false certainty trap
Vulnerability indices are models. Assumptions, data quality, and scale choices influence results. This is why transparency—data sources, methods, and limitations—is essential.
ANOFA perspective: putting the social layer at the center of risk analysis
At ANOFA, we treat the social dimension as central across resilience and risk work—from social vulnerability analysis and city-scale earthquake loss estimation to flood risk assessment and post-disaster recovery monitoring. The core question is always the same: not only “what happens,” but “to whom.”
And one more step matters: these analyses should not remain expert-only reports. They need to be translated into usable decision-support tools—clear GIS products, online maps, dashboards, and robust data workflows that decision-makers and field teams can actually use.