Heterogeneous Slip Distribution Self-Similarity on a Fault Surface

Abstract

The earthquake slip distribution self-similarity is investigated in this study. We complied finite fault slip models for earthquakes in the Taiwan orogenic belt and global earthquakes to determine the slip distribution self-similarity. Forty-one earthquakes (19 Taiwan earthquakes and 22 global earthquakes) in the M w = 4.6 -8.9 magnitude range were examined. The fault slip exhibited self-similar scaling between the rupture slip and area. The average area ratio (R s ) and slip ratio (R d ) follows a scaling of R 10 ( ) s a n Rd = -. Slip self-similarity implies that a fault rupture exhibits fractal behavior. The scaling exponent can be considered as a measure for the roughness degree of the slip distribution on the fault surface. This study suggests that the slip distribution for large earthquakes (M w > 7.0) tends to have a more homogeneous slip. Scaling exponents can provide insight into earthquake rupture mechanics and the scaling of heterogeneous slips on the fault surface provides a basis for ground motion simulation for a finite fault for an earthquake scenario, particularly for near-fault motion.

Synthetic Ground-Motion Simulation Using a Spatial Stochastic Model with Slip Self-Similarity: Toward Near-Source Ground-Motion Validation

“…Finally, we scaled the slipped area partitioned within the finite fault proposed by Lee et al (2016) for slip-distribution heterogeneity. For large earthquakes with M w > 7.0, .…”

“…In addition, they suggested that the slip distribution on a finite fault is the major concern in the forward simulation of earthquake scenarios. To define finite-fault heterogeneity Somerville et al (1999), Murotani et al (2008), and Lee et al (2016) examined earthquakes in California, Japan, and Taiwan, respectively. They reported that in approximately 20% of the total fault rupture area, the slips are 1.5 times larger than the average slip.…”

“…This area, named the area of combined asperities, is considered the area most responsible for generating extreme ground-motion acceleration. Lee et al (2016) analyzed the slip area as a function of slip and found that the fault slip exhibited self-similar scaling between the rupture slip and slip area. For M w > 7.0 earthquakes, slip-distribution scaling in the finite-fault model is similar to logR s = -0.69R d + 0.09, where R d is the ratio of the slip to the mean slip, and R s is the ratio of the fault area to the effective area.…”

“…For M w > 7.0 earthquakes, slip-distribution scaling in the finite-fault model is similar to logR s = -0.69R d + 0.09, where R d is the ratio of the slip to the mean slip, and R s is the ratio of the fault area to the effective area. The self-similarity of earthquake slip distributions has been discussed (Manighetti et al 2005(Manighetti et al , 2007Wesnousky 2008;Klinger 2010;Lee et al 2016) and applied to rupture simulations. Aochi (2005, 2013) and Ide (2009, 2011) proposed a model for the wide-scale growth of dynamic rupture during an earthquake.…”

Fractal and Morlet-wavelet analyses of M ≥ 6 earthquakes in the South-North Seismic Belt, China

“…Mandelbrot (1983) proposed the fractal geometry with fractal dimension to describe the scale-invariant natural phenomena. This concept has been applied to seismology (Turcotte 1989;Korvin 1992), including the fault properties (Aviles et al 1987;Okubo and Aki 1987;Lee and Schwarcz 1995;Candela et al 2012), the spatial distribution of earthquakes (Hirabayashi et al 1992;Turcotte 1997;Wang and Shen 1999), the temporal variation in earthquakes (Smalley et al 1987;Hirata 1989;Kagan and Jackson 1991;Ogata and Abe 1991;Papadopoulos and Dedousis 1992;Koyama et al 1995;Lee 1995, 1997;Wang 1996a;Kagan 2007;Michas et al 2014), and earthquake ruptures (Wang 1995(Wang , 1996bAochi and Ide 2004;Aochi 2005, 2014;Manighetti et al 2005;Lee et al 2016).…”