Big Earth Data (Oct 2024)
Variations in slip rate along the Haiyuan Fault Zone based on geological and geodetic estimations: implications for strain accumulation and seismic hazard
Abstract
Fault slip rates are critical for understanding the evolution of active faults, earthquake recurrence, and crustal deformation. Yet variations in slip rate along the Haiyuan Fault Zone (HYFZ), a large-scale sinistral strike-slip fault in the northeastern margin of the Tibetan Plateau, remain disputed. Here, we investigate in detail late Quaternary and present-day fault slip rates for several segments across the HYFZ based on previously published geologic and geodetic (i.e. GNSS and InSAR) estimates. Our results reveal that the strike-slip rates increase from ~1.6±0.4–1.8±0.3 mm/a on the Halahu (HLH) fault to ~5.2±1.3–6.2±0.9 mm/a on the Lenglongling (LLL) and Jinqianghe (JQH) faults, then decrease to ~3.9±0.8–4.6±0.3 mm/a on the Maomaoshan (MMS) and Laohushan (LHS) faults, subsequently remain relatively constant (i.e. ~4.6±0.8–4.8±0.7 mm/a) on the Haiyuan (HY) fault (in narrow sense), and finally decrease to ~1.3±0.1–1.5±0.3 mm/a on the Liupanshan (LPS) fault, from west to east. These results indicate that the strike-slip rates on the LLL and JQH faults are highest and decrease toward fault tips along the HYFZ, approximating an asymmetrical bell-shaped distribution. Furthermore, geodetic (short-term) and geologic (long-term) slip rates are in general agreement, indicating that the slip rates were relatively constant in the recent geologic history. Despite the shallow creep on the LHS fault, the Tianzhu Seismic Gap, Tuolaishan (TLS), LLL, and LPS faults have a large locking depth, strain accumulation, and/or long seismic quiescence period, underscoring the substantial seismic hazard in these areas. Our study contributes to characterizing the total slip rate budget across the HYFZ and provides insight into further understanding of seismic hazard and regional crustal deformation.
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