A fault with two asperities with different areas and strengths is considered. The fault is treated as a dynamical system with two state variables (the slip deficits of the asperities) and four dynamic modes, for which complete analytical solutions are provided. The seismic events generated by the fault can be discriminated in terms of a variable related with the difference between the slip deficits of the asperities at the beginning of the interseismic interval preceding the event. The effect of the difference between the asperity areas on several features of the model, such as the force rates on the asperities, the slip duration and amplitude, the occurrence of events involving the simultaneous motion of the asperities and the radiation of elastic waves, is discussed. As an application, the \(M_w\) 8.0 2007 Pisco, Peru, earthquake is considered: it is modelled as a two-mode event due to the consecutive failure of two asperities, one almost twice as large as the other. The source function and final seismic moment predicted by the model are found to be in good agreement with observations.
Fault model Asperity model Asperity size 2007 Pisco earthquake
This is a preview of subscription content, log in to check access.
The authors are thankful to the editor Roussos Dimitrakopoulos and to two anonymous referees for their useful comments on the first version of the paper.
Dragoni M, Santini S (2015) A two-asperity fault model with wave radiation. Phys Earth Planet Inter 248:83–93CrossRefGoogle Scholar
Dragoni M, Tallarico A (2016) Complex events in a fault model with interacting asperities. Phys Earth Planet Inter 257:115–127CrossRefGoogle Scholar
Huang J, Turcotte DL (1990) Are earthquakes an example of deterministic chaos? Geophys Res Lett 17:223–226CrossRefGoogle Scholar
Jaeger JC, Cook NGW (1976) Fundamentals of rock mechanics. Chapman & Hall, LondonGoogle Scholar
Lay T, Kanamori H, Ruff L (1982) The asperity model and the nature of large subduction zone earthquakes. Earthq Pred Res 1:3–71Google Scholar
Lay T, Ammon CJ, Hutko AR, Kanamori H (2010) Effects of kinematic constraints on teleseismic finite-source rupture inversions: great Peruvian earthquakes of 23 June 2001 and 15 August 2007. Bull Seismol Soc Am 100(3):969–994CrossRefGoogle Scholar
Sladen A, Tavera H, Simons M, Avouac JP, Konca AO, Perfettini H, Audin L, Fielding EJ, Ortega F, Cavagnoud R (2010) Source model of the 2007 Mw 8.0 Pisco, Peru earthquake: implications for seismogenic behavior of subduction megathrusts. J Geophys Res 115(B2):2156–2202. https://doi.org/10.1029/2009JB006429CrossRefGoogle Scholar
Turcotte DL (1997) Fractals and chaos in geology and geophysics, 2nd edn. Cambridge University Press, CambridgeCrossRefGoogle Scholar