Seismic Hazard Assessment and Ground Motion Modeling

Seismic hazard assessment and ground motion modeling constitute complementary approaches to understanding and mitigating earthquake risk. Seismic hazard assessment evaluates the probability and potential severity of earthquake shaking at a site, integrating geological, seismicity and fault‐slip data through probabilistic or deterministic frameworks. Ground motion modeling seeks to predict the expected intensity, frequency content and duration of shaking, drawing on empirical ground‐motion prediction equations or physics‐based simulations of wave propagation. Together, these disciplines characterise both the likelihood of strong shaking and its spatial and temporal features, underpinning building codes, infrastructure design and emergency planning worldwide. Advances in computational power, high‐resolution subsurface imaging and machine learning have fostered more realistic simulations of heterogeneous geologies, improved quantification of uncertainties and greater regional and site specificity in hazard estimates.

Research from Nature Portfolio

Recent deterministic scenario analyses have demonstrated the value of exhaustive broadband simulations for maximum credible earthquakes (MCEs). By simulating millions of rupture scenarios in three dimensions, researchers have generated spatially continuous ground‐motion fields and synthetic time series across a wide frequency band, yielding more accurate assessments of extreme shaking for critical structures such as large dams. Another study of the 2023 Mw7.8 and Mw7.5 seismic sequence in southeastern Turkey revealed that many regional hazard models underestimated long‐period shaking and exceedance probabilities. Observed excess amplitudes at certain stations highlighted the need for refined characterisation of fault rupture processes, improved empirical models at long periods and incorporation of regional geological effects in future hazard assessments.

Seismic Hazard Assessment and Ground Motion Modeling publication trend

The graph below shows the total number of articles in seismic hazard assessment and ground motion modeling across all publications each year (not limited to Nature Index journals).

Technical terms

Maximum credible earthquake (MCE): The largest magnitude event reasonably possible on a fault, used in deterministic hazard scenarios.

Probabilistic seismic hazard assessment (PSHA): A statistical framework combining earthquake occurrence rates, ground‐motion predictions and uncertainties to estimate shaking exceedance probabilities.

Ground‐motion prediction equation (GMPE): An empirical model relating earthquake magnitude, distance and site conditions to expected shaking intensity measures such as peak acceleration or spectral ordinates.

Deterministic scenario analysis: Evaluation of seismic hazard by simulating specific plausible earthquake ruptures and associated ground motions without probabilistic weighting.

Microtremor horizontal‐to‐vertical spectral ratio (MHVSR): A single‐station technique that uses ambient seismic noise to infer site resonance frequencies and amplification factors.

Aleatory variability: The natural randomness in ground‐motion observations arising from source, path and local site heterogeneity.

Epistemic uncertainty: The lack of knowledge about seismic processes or modelling parameters that can be reduced through improved data and methods.

References

1. Deterministic full-scenario analysis for maximum credible earthquake hazards. Nature Communications (2023).
2. Traditional seismic hazard analyses underestimate hazard levels when compared to observations from the 2023 Kahramanmaras earthquakes. Communications Earth & Environment (2024).
3. Synthetic ground motions in heterogeneous geologies from various sources: the HEMEWS-3D database. Earth System Science Data (2024).
4. A review of the microtremor horizontal-to-vertical spectral ratio (MHVSR) method. Journal of Seismology (2022).
5. A regionally-adaptable ground-motion model for shallow crustal earthquakes in Europe. Bulletin of Earthquake Engineering (2020).