Investigation of Systematic Ground Motion Effects Through Ground Motion Simulation of Small-to-Moderate Magnitude Earthquakes in the Canterbury, New Zealand Region

Robin L. Lee, Brendon A. Bradley, Robert W. Graves, Adrian Rodriguez-Marek, & Peter J. Stafford

Submitted August 8, 2017, SCEC Contribution #7446, 2017 SCEC Annual Meeting Poster #265 (PDF)

This poster presents results of ground motion simulations of small-to-moderate magnitude (3.5<Mw<5.0) earthquake events in the Canterbury region over the past decade, for which centroid moment tensor solutions are available, and an investigation of systematic source and site effects determined via non-ergodic analysis. The simulations are carried out using the GP2010 methodology with the recently developed 3D Canterbury Velocity Model (CantVM). In this study, 144 earthquake ruptures, modelled as point sources, are considered with 1924 quality-assured ground motions recorded at 45 strong motion stations located throughout the Canterbury region. The simulated ground motions, and also empirical prediction equations, are compared with observed ground motions via various intensity measures to quantify their modelling capabilities. The residuals are subsequently separated into between-event and within-event components to determine systematic source and site effects. In particular, this analysis highlights the spatial distribution of the residuals, identifying the areas where bias exists in the ground motion predictions. Lastly, the causes of the biases are identified leading to recommendations which could improve the predictive capabilities of the simulation methodology.

Key Words
New Zealand, ground motion simulation, systematic, non-ergodic

Citation
Lee, R. L., Bradley, B. A., Graves, R. W., Rodriguez-Marek, A., & Stafford, P. J. (2017, 08). Investigation of Systematic Ground Motion Effects Through Ground Motion Simulation of Small-to-Moderate Magnitude Earthquakes in the Canterbury, New Zealand Region. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Ground Motions