[1] Because of short recurrence times and known locations, small repeating earthquakes present a rare predictable opportunity for detailed field observations. They are used to study fault creeping velocities, earthquake nucleation, stress drops, and other aspects of tectonophysics, earthquake mechanics, and seismology. An intriguing observation about repeating earthquakes is their scaling of recurrence time with seismic moment, which is significantly different from the scaling based on a simple conceptual model of circular ruptures with stress drop independent of seismic moment and no aseismic slip. Here we show that a model of repeating earthquakes based on laboratory-derived rate and state friction laws reproduces the observed scaling. In the model, a small fault patch governed by steady state velocity-weakening friction is surrounded by a much larger velocity-strengthening region. Long-term slip behavior of the fault is simulated using a methodology that fully accounts for both aseismic slip and inertial effects of occasional seismic events. The model results in repeating earthquakes with typical stress drops and sizes comparable with observations. For a fixed set of friction parameters, the observed scaling is reproduced by varying the size of the velocity-weakening patch. In simulations, a significant part of slip on the velocity-weakening patches is accumulated aseismically, even though the patches also produce seismic events. The proposed model supplies a laboratory-based framework for interpreting the wealth of observations about repeating earthquakes, provides indirect evidence that rate and state friction acts on natural faults, and has important implications for possible scenarios of slip partition into seismic and aseismic parts.Citation: Chen, T., and N. Lapusta (2009), Scaling of small repeating earthquakes explained by interaction of seismic and aseismic slip in a rate and state fault model,

Citation: Chen, T., and N. Lapusta (2010), Correction to "Scaling of small repeating earthquakes explained by interaction of seismic and aseismic slip in a rate and state fault model," J. Geophys. Res., 115, B09304, doi:10.1029 [1] In the paper "Scaling of small repeating earthquakes explained by interaction of seismic and aseismic slip in a rate and state fault model" by Ting Chen and Nadia Lapusta Figure 8. Ratio of seismic moment M 0 and total moment M total released on the patch for one earthquake cycle as a function of total moment M total for the simulations of Figure 7 with loading rate V L = 23 mm/a. For all simulated cases, a significant portion of the total moment on the patch is released aseismically, from 0.999 to 0.2.

[1] The 3D V p , V p /V s , P-and S-wave attenuation structure of the Cocos subduction zone in Mexico is imaged using earthquakes recorded by two temporary seismic arrays and local stations. Direct P wave arrivals on vertical components and direct S wave arrivals on transverse components from local earthquakes are used for velocity imaging. Relative delay times for P and PKP phases from teleseismic events are also used to obtain a deeper velocity structure beneath the southern seismic array. Using a spectral-decay method, we calculate a path attenuation operator t* for each P and S waveform from local events, and then invert for 3D spatial variations in attenuation (Q p À1 and Q s À1 ). Inversion results reveal a low-attenuation and high-velocity Cocos slab. The slab dip angle increases from almost flat in central Mexico near Mexico City to about 30 in southern Mexico near the Isthmus of Tehuantepec. High attenuation and low velocity in the crust beneath the Trans-Mexico Volcanic Belt correlate with low resistivity, and are probably related to dehydration of the slab and melting processes. The most pronounced high-attenuation, low-V p and high-V p /V s anomaly is found in the crust beneath the Veracruz Basin. A high-velocity structure dipping into the mantle from the side of Gulf of Mexico coincides with a discontinuity from a receiver functions study, and provides an evidence for the collision between the Yucatán Block and Mexico in the Miocene.

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Elastic properties of antigorite are important for interpretation of seismic mapping of serpentinization in the mantle wedge above subducting slabs. The compressional (VP) and shear (VS) wave velocities in pure antigorite aggregates were measured simultaneously up to 8.4 GPa by ultrasonic interferometry. We found that VP increases monotonically with pressure while VS increases with pressure up to about 3 GPa but undergoes a negative pressure dependence above 4 GPa. Compared to other mantle minerals, antigorite exhibits significantly lower P and S wave velocities as well as a higher VP/VS ratio at upper mantle pressures. We modeled velocity reductions manifesting through the formation of antigorite in mantle peridotite and provide compelling evidence that seismic anomalies with low‐velocity and high VP/VS ratios is caused by varying degrees of serpentinization in subduction zones.