Excitation of Earth's inner core rotational oscillation during 2001–2003 captured by earthquake doublets

• Inner core differential rotation is highly time-varying during 1991–2017. was nearly locked to mantle before 2001 and after 2003. experienced a burst of 2001–2003. The may have excited the six-year oscillation in length-of-day. nature any between Earth's inner important for understanding magnetic field intradecadal variations length-of-day; however, consensus on existence rate still lacking 25 years. reported model from seismic body waves controversial might be explained by non–rotational processes. Here, we explore using decorrelation inner-core sensitive coda 123 earthquake doublets recorded We find that 2003 with relatively small motion about an equilibrium position. During 2001–2003 rotation, possibly response torque induced expulsion light elements core. suggest this fleeting bit rotational helped excite oscillation, consequently exciting six-year-oscillation