Open-File Report 2008–1236
An atlas of maps of peak ground motions and intensity “ShakeMaps” has been developed for almost 5,000 recent and historical global earthquakes. These maps are produced using established ShakeMap methodology (Wald and others, 1999c; Wald and others, 2005) and constraints from macroseismic intensity data, instrumental ground motions, regional topographically-based site amplifications, and published earthquake-rupture models. Applying the ShakeMap methodology allows a consistent approach to combine point observations with ground-motion predictions to produce descriptions of peak ground motions and intensity for each event. We also calculate an estimated ground-motion uncertainty grid for each earthquake.
The Atlas of ShakeMaps provides a consistent and quantitative description of the distribution and intensity of shaking for recent global earthquakes (1973–2007) as well as selected historic events. As such, the Atlas was developed specifically for calibrating global earthquake loss estimation methodologies to be used in the U.S. Geological Survey Prompt Assessment of Global Earthquakes for Response (PAGER) Project. PAGER will employ these loss models to rapidly estimate the impact of global earthquakes as part of the USGS National Earthquake Information Center’s earthquake-response protocol.
The development of the Atlas of ShakeMaps has also led to several key improvements to the Global ShakeMap system. The key upgrades include: addition of uncertainties in the ground motion mapping, introduction of modern ground-motion prediction equations, improved estimates of global seismic-site conditions (VS30), and improved definition of stable continental region polygons. Finally, we have merged all of the ShakeMaps in the Atlas to provide a global perspective of earthquake ground shaking for the past 35 years, allowing comparison with probabilistic hazard maps. The online Atlas and supporting databases can be found at http://earthquake.usgs.gov/eqcenter/shakemap/atlas.php/.
Posted August 2008
Allen, T.I., Wald, D.J., Hotovec, A.J., Lin, K., Earle, P.S. and Marano, K.D., 2008, An Atlas of ShakeMaps for Selected Global Earthquakes: U.S. Geological Survey Open-File Report 2008–1236, 35 p.
Selection of Events
Earthquake Observations & Constraints
Instrumental Ground Motions
Relationships between Peak Ground-Motions and Intensities
Ground-Motion Prediction Equations Used
Regional Site Response Corrections
Putting it all Together—Constructing a ShakeMap
Quantifying Ground-Motion Uncertainties
Quantitative Shaking Uncertainty Calculations
Qualitative Uncertainty Assignments
ShakeMap Atlas Products
Composite Global ShakeMap
Appendix I – List of Calibrated ShakeMaps
Appendix II – References to Atlas Data Sources
Appendix III – Complete List of Atlas Events