Late Quaternary Segment Faulting Behavior of Yilan-Yitong Fault and Its Potential Seismic Hazards, NE China, by Using Multisource Remote Sensing Data

Quantitative investigation of major fault zones with low slip rates and long recurrence intervals in densely populated regions is essential for understanding earthquake recurrence and assessing seismic hazard. The Tanlu Fault Zone, a major lithospheric boundary extending from eastern China into Russia, provides a key case study. Through remote sensing interpretation integrated with seismic-geological evidence, we identified a ~150 km-long fresh surface rupture zone along the Yilan–Yitong Fault in the Fangzheng–Tangyuan region of Heilongjiang Province, NE China. Chronological constraints from previous and recent trenching indicate that the most recent event occurred in the late Holocene, with an estimated magnitude of Mw ≈ 7.6, comparable to the scale of AD 1668 Tancheng earthquake in North China. The northeastern section of the Tanlu Fault Zone is also subject to long-term far-field Coulomb stress loading from subduction of the Pacific Plate beneath the Eurasian Plate. Although the fault exhibits long recurrence intervals, the urgency of future strong earthquakes cannot be overlooked. Furthermore, our results suggest that the northeastern Tanlu Fault Zone is characterized by segmentation, underscoring the need for refined paleoseismic investigations to constrain recurrence behavior and seismic hazard in Northeast China.