Global Earthquake Model (GEM): Advancing Worldwide Seismic Risk Assessment
Between 2000 and 2010, earthquakes and tsunamis claimed more than half a million lives. The majority of these fatalities occurred in the developing world, where rapid urbanization and population growth significantly heighten vulnerability. Despite these risks, many earthquake-prone regions lack accessible risk models, making it difficult to implement effective safety measures.
To address this critical gap, the Global Earthquake Model (GEM) was established as a public–private partnership. Initiated in 2006 by the OECD's Global Science Forum, GEM aims to develop open-source software and tools to assess earthquake risk on a global scale. By providing standardized data, GEM helps drive better construction practices, improved emergency responses, and increased access to insurance, ultimately working toward the goals set by the Hyogo Framework for Action.
Key Facts
- Founded: Initiated in 2006; established as a non-profit foundation in March 2009.
- Headquarters: Pavia, Italy, with the Secretariat hosted at EUCENTRE.
- Core Objective: To provide open-source, authoritative tools for calculating and communicating earthquake risk.
- Scientific Approach: Utilizes an integrated framework of seismic hazard, seismic risk, and socio-economic impact.
- Structure: A public–private partnership involving academia, government, and industry.
The Scientific Framework of GEM
The GEM scientific framework is the foundation of its global model. It is organized into three integrated modules designed to provide a comprehensive view of seismic threats.
1. Seismic Hazard Module
The seismic hazard module calculates the probability of an earthquake occurring and the intensity of the resulting ground shaking at any specific location. This provides the baseline data necessary to understand where the most intense shaking is likely to happen.
2. Seismic Risk Module
The seismic risk module translates physical shaking into tangible consequences. It calculates potential damage and direct losses, such as fatalities, injuries, and repair costs. This calculation is achieved by combining three critical factors: building vulnerability, population vulnerability, and exposure. To improve accuracy, GEM is developing techniques using remote sensing and crowd-data collection to monitor and update building inventories.
3. Socio-Economic Impact Module
Beyond physical damage, the socio-economic impact module estimates how earthquakes affect society and the economy. It focuses on indirect losses, such as impacts on company revenues, national budgets, and poverty levels. These tools allow for cost/benefit analyses of mitigation strategies, such as systematic building strengthening, and support the development of insurance and alternative risk transfer mechanisms.
Implementation and Model Development
Building a working global earthquake model is a complex, multi-stage process. The initial construction phase began in 2009 and was scheduled for completion by the end of 2013. This development involves several layers of data and collaboration:
- Global Components: These establish common definitions, standards, and quality criteria. They provide preliminary data on a global scale and include projects like the Global GMPEs, which proposes ground motion prediction equations.
- Regional and National Programmes: These provide more detailed and reliable data. For example, programs in Europe and the Middle East have already been completed.
- Web-Based Platform: All development occurs on a common platform to allow for the dynamic sharing of tools and resources, resulting in end-user software and online tools.
Before official release, the model undergoes rigorous testing through reproducible and transparent scientific experiments in controlled environments to ensure accuracy and reliability.
| Module | Primary Focus | Key Outputs |
|---|---|---|
| Seismic Hazard | Probability of occurrence | Harmonized shaking probabilities |
| Seismic Risk | Physical damage and loss | Fatalities, injuries, and repair costs |
| Socio-Economic Impact | Economic and societal effects | Indirect losses, revenue impact, and cost/benefit analysis |
Frequently Asked Questions
What is the main goal of the Global Earthquake Model?
The main goal is to develop open-source, global risk assessment tools that provide an authoritative standard for calculating and communicating earthquake risk to reduce worldwide vulnerability.
How does GEM calculate seismic risk?
GEM calculates risk by combining building vulnerability, population vulnerability, and exposure to determine the resulting damage and direct losses, such as injuries and repair costs.
Who is involved in the GEM partnership?
GEM is a public–private partnership that includes committed backing from academia, various governments, and industry sectors.
Where is the GEM Secretariat located?
The GEM Secretariat is hosted at the European Centre for Training and Research in Earthquake Engineering (EUCENTRE) in Pavia, Italy.
What are indirect socio-economic losses?
Indirect losses refer to the economic impacts that follow an earthquake, such as changes in a company's revenue, impacts on national budgets, and the effects on poverty levels.