Incorporating Directly Observed Rotational Seismic Data into Moment Tensor Inversion for the 2019 Mw 6.2 Hualien Earthquake

Abstract Rotational observations offer significant benefits in various fields of seismology. In recent years, fiber-optic rotational seismometers have recorded high-quality rotational waveform data, which could be used for seismological researches. In this study, we introduce directly observed rotational data into moment tensor inversion for the first time. In inversions of the 2019 Mw 6.2 Hualien earthquake, we confirm the improved constraints on moment tensor solutions and centroid depth achieved with the additional use of rotational data. Particularly, inversions of six-component (6C) records from 1 to 2 stations yield acceptable results, indicating potential applications of sparse-network observations to planetary seismology. With the increasing deployment of rotational seismometers, as well as the improvements of these seismographs in sensitivity and frequency range, rotational records will further contribute to seismological researches on Earth and other solid planets, playing a crucial role in probing deep structures and refining source parameters.