# Quaternary Segmentation Characteristics of the Hunhe Fault, Northeast China
## 4 Results
### Fushun Segment  
1 The fault structure and deformational characteristics of the fault  
Distributed on both the southern and northern sides of the Fushun Basin, the fault extends 30 km and consists of 2-3 main branches, with the development of small secondary faults (Figure 5). The structure is characterized by parallel, oblique, and composite branching patterns, exhibiting a loose structure. The southern branch has relatively good continuity, and the fault traces are clear, with a significant variation in spacing, generally ranging from 2 to 7 km. This forms a trumpet-shaped fault depression, oriented from NEE  
Figure 4: Small gullies related to faults on the Hunhe gentle alluvial plain (photo courtesy of [PERSON]).  
to nearly east-west. The western end is inclined to the north, while the eastern end is inclined to the south, with a steep dip angle of approximately 50\({}^{\circ}\)-75\({}^{\circ}\). The most recent movement characteristics are right-lateral strike-slip combined with normal dip-slip.  
2 Transverse faults and obstruction structures  
The fault depression basin on the western edge of the Liaodong Mountain area is bounded to the west by the Lower Liaobe Basin and to the east by the NE-trending Xiahada fault and the uplift of the Liaodong Mountain bedrock. There is a structural step between the fault segments on both sides.  
* 3 Geological and geomorphological characteristics  
The fault controls the development of the Fushun Quaternary basin and the morphology of the Hunhe River valley. There are significant differences in the macro-topography on both sides of the main fault, with visible micro-topographic features such as steep cliffs and slopes in the mountainous areas (Figure 6). However, no fault scarps have been observed on the first and second terraces where the fault passes through. Along the fault, a complete and continuous fault depression basin has formed, with Quaternary deposits that are continuous but relatively less complete, with a thickness of about 10-20 m, gradually deepening from east to west and exhibiting a gentle gradient.  
* 4 Seismic features  
Located in the Jiao-Liao uplift, the Tieling-Jingyu anticline marks the boundary between the Panhe sag and the Fushun uplift. The fault plays a key role in shaping the development of both the basement and the overlying strata. Paleogene formations, characterized by thick coal-bearing layers, are distributed in a belt along the fault zone. Early reverse thrusting caused Archean strata to override Cretaceous layers, which were subsequently thrust over Paleogene formations, resulting in the inversion of the coal-bearing strata. Within the broader context of gradual uplift, a graben-style depression belt has developed along the main southern and northern branches of the Hunhe fault. The scale of the fault zone is large. The vertical displacement of the fault is 550-600 m, and the  
Figure 5: Detailed structure and seismic tectonic map of the Hunhe fault in the Fushun segment.  
horizontal displacement is 250-400 m. Features such as structural lens bodies, fault gouge, claystone, crushed rock, and mylonitic structures are developed.  
\(\bullet\) 5 Fault activity  
Multiple periods of activity are observed, with significant extension activity during the Paleogene (Figure 6), which subsequently weakened considerably. The new Quaternary activity further diminished, with the most recent active period being MIS 20-103-MIS6-19, characterized by relatively low activity levels.  
Figure 6: Fault movement surface of the Hunhe fault zone (photo courtesy of [PERSON]). The red arrows show the fault fracture zone of Hunhe fault in the lower photo. The black frame in the upper photo indicates the location of lower photo.