tokens: FRB repeater exhibits several features commonly found in earthquakes. In fact, nonlinear dissipative systems always show self-organized criticality (SOC) behaviors. With a solid crust or stiff equation of state (EOS) of a pulsar, a star can build up stresses that make the crust crack and adjust the stellar shape in order to reduce its deformation. The characters for these processes of statistical independence, nonlinear coherent growth, and random rise times are consistent with an SOC system (Aschwanden 2011 ). According to the SOC theory, NS quakes are giant catastrophic events like earthquakes, and are probably accompanied by global seismic vibrations or oscillations. Hence, starquakes in a pulsar share similar statistical distributions with earthquakes. Here we present two possible scenarios. One scenario involves a normal NS with a solid crust and a superfluid core, and with a strong toroidal magnetic field (i.e., magnetar). An NS can form a solid crust quickly after its birth. The stellar shape changes from oblate to spherical configuration, and thermal and dynamic responses will induce stresses in the crusts. When stress buildup in the dense solid crust extends beyond a yield point a starquake occurs, with a sudden energy release that supports FRBs. This process also brings a slight change in the moment of inertia, with an abrupt jump of angular frequency that is the so-called pulsar glitch (Ruderman 1969 ; Link Epstein 1996 ). For a highly magnetized NS, the stellar crust couples with the magnetosphere. In this scenario, starquakes induce the magnetic curl or twist ejected into the magnetosphere from the crust in a few milliseconds (Thompson et al. 2002 , 2017 ). Electrons in the magnetosphere are suddenly accelerated to ultra-relativistic velocity by magnetic reconnection (Zhang Yan 2011 ) and move along the magnetic field lines, resulting in the production of curvature radiation. The characteristic frequency of the curvature radiation iswhere R c is the curvature radius with a typical value of ∼10 km, and γ is the Lorentz factor of electrons. With a detected FRB frequency ν c = 4–8 GHz, a γ ≈ 50–100 is required. If generated by such stress-induced reconnections (e.g., Lyutikov 2015 ), the FRB has an estimated duration timescalewhere the scale of the reconnection-unstable zone L ∼ 1–10 km, and the Alfvén velocity is v A ≃ B /(4 πρ c ) 1/2 ∼ 0.01 c , in which ρ c ≃ 10 14 g cm −3 is the average mass density of the crust. The sudden elastic and magnetic energy release in the crustal stress is estimated to bewhere h c ≃ R /30 ≃ 0.3 km is the crustal thickness (Thompson et al. 2017 ), ε is the shear strain, and the total stress including crustal shear stress and Maxwell stress in magnetosphere isin which μ is the shear modulus, B is the surface magnetic field, and B z is the component of magnetic field perpendicular to the direction of plastic flow. Within the crust, the force balance με ≃ BB z /(4 π ) implies that is smaller than ∼10 −2
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