The dependence of traction evolution on the earthquake source time function adopted in kinematic rupture models

Abstract

[1] We compute the temporal evolution of traction by solving the elasto-dynamic equation and by using the slip velocity history as a boundary condition on the fault plane. We use different source time functions to derive a suite of kinematic source models to image the spatial distribution of dynamic and breakdown stress drop, strength excess and critical slip weakening distance (D c ). Our results show that the source time functions, adopted in kinematic source models, affect the inferred dynamic parameters. The critical slip weakening distance, characterizing the constitutive relation, ranges between 30% and 80% of the total slip. The ratio between D c and total slip depends on the adopted source time functions and, in these applications, is nearly constant over the fault. We propose that source time functions compatible with earthquake dynamics should be used to infer the traction time history.

Constitutive parameters for earthquake rupture dynamics based on high-velocity friction tests with variable sliprate

“…And it is pointed out that a tiny change in slip velocity function results in very different slip weakening behaviors (Piatanesi et al 2004;Tinti et al 2009). Mikumo et al (2003) and Fukuyama et al (2003) proposed a technique for the estimation of slip weakening distance from the slip time function on the fault.…”

Fault-Zone Properties and Earthquake Rupture Dynamics

“…As discussed above, the inadequate resolution and the limited frequency bandwidth, which characterize inverted kinematic models, reduce the ability to infer the real dynamic traction evolution everywhere on the fault plane. Many recent papers have investigated the limitations of using poorly resolved kinematic source models (Guatteri and Spudich, 2000;Piatanesi et al, 2004;Spudich and Guatteri 2004). We discuss these issues in further detail below.…”

“…Moreover, source time functions compatible with earthquake dynamics and suitable for waveform inversions are becoming commonly available (see Piatanesi et al, 2004;Tinti et al, 2005b;Dreger et al, 2007;Cirella et al, 2006). Finally, Tinti et al (2005a and have discussed in detail the fidelity of calculations of breakdown work and D c and concluded that, in agreement with Guatteri and Spudich (2000), the estimates of W b are quite stable despite the limited available resolution in kinematic source models, while the D c parameter is more difficult to constrain.…”

“…1) limitations in our ability to model seismic waveforms given the narrow frequency bandwidths available (i.e., lack of high frequency components, see Spudich and Guatteri, 2004 and references therein), 2) adoption of source time functions that are not compatible with dynamic rupture propagation (see Piatanesi et al, 2004), and 3) the lack of causality constraints on spatial and temporal evolution of slip velocity in seismic inversions (i.e., poor constraints on spatial gradient of slip velocity, see for details). The duration of the breakdown process and the peak slip velocity depend on the frictional and constitutive properties of the fault.…”

“…In this paper, we further discuss the validity of using as an alternative seismological estimate of . As noted by Piatanesi et al (2004), the use in kinematic modelling of source time functions not compatible with the dynamic rupture propagation could bias the estimate of D c and hence the inferred ratio of D c to the total slip D tot . Based on these results Tinti et al (2005b) proposed the use of a new source time function to infer kinematic source models consistent with earthquake dynamics, which they named the regularized Yoffe function (shown in Figure 1a, see Tinti et al, 2005b, for the details of its analytical parameterization).…”