Earthquake_Moment_Area_Scaling
In the paper we used QDYN to simulate earthquake cycles and obtained events spanning a broad range of magnitudes to study earthquake scaling relations:
Y. Luo, J. P. Ampuero, K. Miyakoshi and K. Irikura (2017)
Surface effects on earthquake moment-area scaling relations
PAGEOPH, Topical Volume on "Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations"
doi:10.1007/s00024-017-1467-4 PDF
Empirical earthquake scaling relations play a centralrole in fundamental studies of earthquake physics and in currentpractice of earthquake hazard assessment, and are being refined byadvances in earthquake source analysis. A scaling relation betweenseismic moment (M0) and rupture area (A) currently in use for ground motion prediction in Japan features a transition regime of the form M0–A^2, between the well-recognized small (self-similar) and very large (W-model) earthquake regimes, which has counter-intuitive attributes and uncertain theoretical underpinnings.
Figure 1. Earthquake M0–A scaling in empirical data, synthetic catalogs and theoretical models. Green circles strike-slip earthquake data (fromkinematic inversion of vertical strike-slip faults (Somerville et al.1999; Miyakoshi et al. 2015; Murotani et al. 2015)). Green curve empirical 3-stage relation. Red circles and squares synthetic earthquake data from earthquake cycle simulations of ‘‘reduced-scale’’ and ‘‘full-scale’’ models, respectively. Dark blue curve dislocation model with free surface. Grey curve crackmodel. Black curve proposed simple equation with best fitting. The crack model fits the data better than the dislocation model, and the simple equation fits both the simulation and observation data extremely well.
Figure 2 Rupture geometry in different models considered in this study. a Dislocation model with square to rectangular rupture transition. b Crackmodel with circular to elongated rupture transition. c Rate-and-state model with self-similar to elongated rupture transition. The free surfacemirror image effect applies to all models. The ‘attractor effect’ (coalescence between real and mirror image ruptures) enhances Stage 2 in therate-and-state model
Figure 3 Rate-and-state model settings. Left effective normal stress (blue curve) and a/b ratio (red curve) as a function of depth. The seismogenic zone(a/b< 1) extends roughly from 2 to 20 km depth. Right an example of heterogeneous distribution of characteristic slip distance Dcwithcorrelation length of 1 km