GEM2018 | globalquakemodel

The Global Earthquake Model (GEM) Global Seismic Hazard Map (version 2018.1) depicts the geographic distribution of the Peak Ground Acceleration (PGA) with a 10% probability of being exceeded in 50 years, computed for reference rock conditions (shear wave velocity, V , of 760-800 m/s). The map was created by collating maps computed using national and regional probabilistic seismic hazard models developed by various institutions and projects, and by GEM Foundation scientists. The OpenQuake engine, an open-source seismic hazard and risk calculation software developed principally by the GEM Foundation, was used to calculate the hazard values. A smoothing methodology was applied to homogenise hazard values along the model borders. The map is based on a database of hazard models described using the OpenQuake engine data format (NRML); those models originally implemented in other software formats were converted into NRML. While translating these models, various checks were performed to test the compatibility between the original results and the new results computed using the OpenQuake engine. Overall the differences between the original and translated model results are small, notwithstanding some diversity in modelling methodologies implemented in different hazard modelling software. The hashed areas in the map (e.g. Greenland) are currently not covered by a hazard model. The map and the underlying database of models are a dynamic framework, capable to incorporate newly released open models. Due to possible model limitations, regions portrayed with low hazard may still experience potentially damaging earthquakes. The GEM Foundation plans to release future updates of this map on a regular basis as new information becomes available. Technical details on the compilation of the hazard and risk maps and the underlying models are available at http://www.globalquakemodel.org/gem.

How to use and cite this work

Please cite this work as: M. Pagani, J. Garcia-Pelaez, R. Gee, K. Johnson, V. Poggi, R. Styron, G. Weatherill, M. Simionato, D. Viganò, L. Danciu, D. Monelli (2018). Global Earthquake Model (GEM) Seismic Hazard Map (version 2018.1 - December 2018), DOI: 10.13117/GEM-GLOBAL-SEISMIC-HAZARD-MAP-2018.1 This work is licensed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA): https://creativecommons.org/licenses/by-nc-sa/4.0/.

Acknowledgements

This map is the result of a collaborative effort and extensively relies on the enthusiasm and commitment of various organisations and projects to openly share and collaborate. The creation of this map would not have been possible without the support provided by many public and private organisations during GEM’s second implementation phase (2014-2018). These key contributions are profoundly acknowledged. None of this would have been possible without the extensive support of all GEM Secretariat staff. The map was plotted using the Generic Mapping Tools software (Wessel et al., 2013).

Legal statements

This map was created for dissemination purposes. The information included in this map must not be used for the design of earthquake-resistant structures or to support any important decision involving human life, capital and movable and immovable properties. The values of seismic hazard in this map do not constitute an alternative nor do they replace building actions defined in national building codes. Readers seeking this information should consult national databases. This hazard map is the combination of results computed using 30 hazard input models covering the vast majority of landmass. These models represent the best information publicly accessible, and the GEM Foundation recognises their credibility and authoritativeness. This hazard map results from an integration process that is solely the responsibility of the GEM Foundation.

Global Earthquake Model (GEM) Global Seismic Risk Map

The Global Seismic Risk Map (v2018.1) comprises four global maps. The main map presents the geographic distribution of average annual loss (USD) normalised by the average construction costs of the respective country (USD/m2) due to ground shaking in the residential, commercial and industrial building stock, considering contents, structural and non-structural components. The normalised metric allows a direct comparison of the risk between countries with widely different construction costs. It does not consider the effects of tsunamis, liquefaction, landslides, and fires following earthquakes. The loss estimates are from direct physical damage to buildings due to shaking, and thus damage to infrastructure or indirect losses due to business interruption are not included. The Global Seismic Hazard Map depicts the geographic distribution of the Peak Ground Acceleration (PGA) with a 10% probability of being exceeded in 50 years, computed for reference rock conditions (shear wave velocity of 760-800 m/s). The Global Exposure Map depicts the geographic distribution of residential, commercial and industrial buildings. The Global Seismic Fatalities Map depicts an estimate of average annual human losses due to earthquake-induced structural collapse of buildings. The results for human losses do not consider indirect fatalities such as those from post-earthquake epidemics. The average annual losses and number of buildings are presented on a hexagonal grid, with a spacing of 0.30 x 0.34 decimal degrees (approximately 1,000 km2 at the equator). The average annual losses were computed using the event-based calculator of the OpenQuake engine, an open-source software for seismic hazard and risk analysis developed by the GEM Foundation. The seismic hazard, exposure and vulnerability models employed in these calculations were provided by national institutions, or developed within the scope of regional programs or bilateral collaborations. These global maps and the underlying databases are based on best available and publicly accessible datasets and models. Due to possible model limitations, regions portrayed with low risk may still experience potentially damaging earthquakes. The GEM Risk Map is intended to be a dynamic product, such that it may be updated when new datasets and models become available. Releases of updated versions of the seismic risk map are anticipated on a regular basis. Additional hazard and risk metrics for each country can be explored at globalquakemodel.org/gem.

How to use and cite this work

Please cite this work as: V. Silva, D. Amo-Oduro, A. Calderon, J. Dabbeek, V. Despotaki, L. Martins, A. Rao, M. Simionato, D. Viganò, C. Yepes-Estrada, A. Acevedo, H. Crowley, N. Horspool, K. Jaiswal, M. Journeay, M. Pittore (2018). Global Earthquake Model (GEM) Seismic Risk Map (version 2018.1), DOI: 10.13117/GEM-GLOBAL-SEISMIC-RISK-MAP- 2018. This work is licensed under the terms of the Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA).

Acknowledgements

This map is the result of a collaborative effort and extensively relies on the enthusiasm and commitment of various organisations to openly share and collaborate. The creation of this map would not have been possible without the support provided by several public and private organisations during GEM’s second working programme (2014-2018). None of this would have been possible without the extensive support of all GEM Secretariat staff. These key contributions are profoundly acknowledged. A complete list of the contributors can be found at globalquakemodel.org/gem.

Legal statements

This map is an informational product created by the GEM Foundation for public dissemination purposes. The information included in this map must not be used for the design of earthquake-resistant structures or to support any important decisions involving human life, capital and movable and immovable properties. The values of seismic hazard and risk in this map do not constitute an alternative nor do they replace building actions defined in national building codes or earthquake risk estimates derived nationally. Readers seeking this information should contact the national authorities tasked with seismic hazard and risk assessment. The seismic risk map results from an integration process that is solely the responsibility of the GEM Foundation.