SEISMOLOGY AND GEOLOGY ›› 2026, Vol. 48 ›› Issue (1): 19-42.DOI: 10.3969/j.issn.0253-4967.20240075

• Research pape • Previous Articles     Next Articles

LATE-QUATERNARY ACTIVITY OF THE XUSHUI SOUTH FAULT AND NIUDONG FAULT IN THE NORTH OF THE NORTH CHINA PLAIN, EVIDENCE FROM DRILLING

HUANG Xiong-nan1)(), YANG Xiao-ping1),*, LIU Bao-jin2), SHI Feng1), ZHUANG Qi-tian3), HAO Hai-jian1), SHI Jin-hu2), SUN Hao-yue1), LU Ren-qi1), HU Zong-kai1), LI Kang1), CAO Jun1,4), SHU Peng1), REN Guang-xue1), WANG Zhen-nan1)   

  1. 1) State Key Laboratory of Earthquake Dynamics and Forecasting, Institute of Geology, China Earthquake Administration, Beijing 100029, China
    2) Geophysical Exploration Center, China Earthquake Administration, Zhengzhou 450002, China
    3) POWER CHINA Kunming Engineering Corporation Limited, Yunnan 650000, China
    4) Hebei Earthquake Agency, Shijiazhuang 050021, China
  • Received:2025-05-31 Revised:2025-10-24 Online:2026-02-20 Published:2026-03-14

华北平原北部徐水南断裂和牛东断裂晚第四纪活动性——来自钻孔联合地质剖面的证据

黄雄南1)(), 杨晓平1),*, 刘保金2), 石峰1), 庄其天3), 郝海健1), 石金虎2), 孙浩越1), 鲁人齐1), 胡宗凯1), 李康1), 曹筠1,4), 疏鹏1), 任光雪1), 王振南1)   

  1. 1) 地震动力学与强震预测全国重点实验室(中国地震局地质研究所), 北京 100029
    2) 中国地震局地球物理勘探中心, 郑州 450002
    3) 中国电建集团昆明勘测设计研究院有限公司, 昆明 650000
    4) 河北省地震局, 石家庄 050021
  • 通讯作者: * 杨晓平, 男, 1962年生, 研究员, 主要研究方向为活动构造及地震危险性评价, E-mail: yangxiaoping-1@163.com。
  • 作者简介:

    黄雄南, 男, 1974年生, 2003年于北京大学获构造地质学专业博士学位, 副研究员, 主要研究方向为活动构造与地震地质, E-mail:

  • 基金资助:
    中国地震局地质研究所基本科研业务专项(IGCEA1902)

Abstract:

Since the Late Pleistocene, the North China Plain, far from plate boundaries, has experienced a transformation in its geodynamic environment, with most pre-existing normal faults no longer adapting to the new tectonic stress field and thus becoming inactive. However, historical and modern earthquake catalogues indicate that the epicenters of many strong earthquakes occur near pre-existing buried normal faults on the North China Plain. There is currently a debate over whether strong earthquakes are caused by the continued activity of these pre-existing faults or by new faults.

The Xiong'an New Area is located in the northern part of the North China Plain. Based on seismic reflection profiles and drilling studies, previous studies suggest that some pre-existing faults in this region were active into the early Quaternary but have been inactive since the Late Pleistocene. Relevant research lacked evidence from high-precision composite drilling profile investigations, making the conclusion about inactivity since the Late Pleistocene questionable. The crust-mantle structure in this area is unique, the mantle is uplifted and there is deep fluid convection along pre-existing faults, which is similar to typical intraplate seismic zones in the world, such as the New Madrid area in the United States. The epicenter of the M5¾ earthquake in 1679 was located in the study area. The determination of the latest active age of the fault is of great significance for the seismic hazard assessment of Xiong'an New Area and further research is needed. In this paper, based on shallow seismic exploration, we analyze the burial depth of the upbreakpoints of the Xushui South Fault and the Niudong Fault in the Xiong'an New Area using a composite drilling profile method, and then determine fault activity using Quaternary dating methods.

The targeted shallow reflection seismic explorationwith survey lines laid across the Xushui South Fault and the Niudong Fault has confirmed that the upper breakpoints of the middle section of the Xushui South Fault and the eastern branch of the middle section of the Niudong Fault are both at a depth of about 80 meters or less. This result may indicate the Xushui South Fault and the Niudong Fault were active during the Late Pleistocene. Perpendicular to the projection traces of the upper breakpoints of these two faults, two composite drilling profiles were arranged with boreholes on both sides of the shallowest identified upper breakpoints. They are named as the Rongcheng drilling profile and Xiongxian drilling profile, respectively. The drilling profiles consist of 5 and 4 drill holes, respectively, and the final hole depth is approximately 150 meters for both. The average hole separations were 23.3m and 30.4m respectively.

Based on material composition, particle size, color and consolidation degree, etc., we divided and recorded 104 and 112 units respectively for the two rows of drilling cores at the drilling site. After a comprehensive analysis, the detailed units mentioned above are reclassified and combined into 8 and 9 stratigraphic units, according to sedimentary cycles, sedimentary facies and other characteristics, and in combination with the dating results. These units cover the Holocene to the low Pleistocene series. The systematic throws of the top and bottom boundaries of the stratigraphic units and the fault zone structures preserved in the core led to the recognition of two normal faults in both the Rongcheng and Xiongxian drilling profiles. The faults in the Rongcheng profile have an up-breakpoint buried approximately 24m deep and the vertical offset of the base of the Upper Pleistocene is 15.15m. For the Xiongxian drilling line, the buried depth of the up-breakpoint of the faults is about 42m, with a vertical offset at the base of the Upper Pleistocene of 9.1m. The dating results of the samples collected near the up-breakpoints suggest that the middle segment of the Xushui South Fault and the eastern branch of the Niudong Fault were still active around approximately 20,000 years and 36,000 years ago, respectively, indicating they are Late Pleistocene faults.

Since the Paleogene, the Xushui South Fault and the Niudong Fault have been active as bounding normal faults for the Rongcheng Uplift and the Niutuo Town Uplift, with their lower endpoints reaching depths of approximately 20 kilometers. The lithosphere beneath these faults exhibits a cold crust and a warm mantle, with a slight bulge in the upper mantle. The Xushui South Fault and the Niudong Fault serve as conduits for the ascent of deep fluids and heat. The geothermal gradient in the uplifted areas is notably higher than in the surrounding subsiding basins. Our work indicates that these faults remained active in a normal faulting mode at the end of the Late Pleistocene. Combined with previous shallow seismic exploration, it’s suggested that the Xushui South Fault and the Niudong Fault were only active in their central segments after the Late Pleistocene.

Although the activity of these faults has diminished since the Late Quaternary, their deep-seated environment is similar to that of the New Madrid Seismic Zone in the United States, where a soft, warm upper mantle contacts a cooler, harder crust, and uneven crustal density leads to stress accumulation preferentially along pre-existing faults. Additionally, these faults act as pathways for deep fluids, which can trigger strong earthquakes.

The continued activity of the Xushui South Fault and the Niudong Fault at the end of the Late Pleistocene is related to their deep-seated environment. Some historical strong earthquakes in the North China Plain may have been triggered by reactivation of pre-existing faults with similar characteristics.

Key words: composite drilling profile, fault activity, Xiong'an, North China Plain

摘要:

华北平原新生代正断裂大多在晚更新世以来停止活动, 但大量历史强震震中却位于这些隐伏断裂的附近。那么, 强震是先存正断裂的继续活动还是新生断裂造成的?文中通过钻孔探测结合年代学测定, 研究雄安新区徐水南断裂和牛东断裂晚第四纪活动性, 探讨华北平原区新生代先存正断裂的继承性活动及其机制。钻孔联合剖面探测确定徐水南断裂中段和牛东断裂中段东支的上断点分别深约24m和42m。测年结果表明, 断裂分别在距今约20ka和36ka仍然活动, 皆为晚更新世断层。结合浅层地震勘探, 可知徐水南断裂和牛东断裂晚更新世之后活动性减弱, 仅在中段活动。徐水南断裂和牛东断裂作为容城凸起和牛驼镇凸起的边界断层, 其深部具有特殊的岩石圈结构, 断裂易于积累应变, 且又为深部流体通道, 虽然晚第四纪以来活动性减弱, 但仍有可能被触发, 从而发生强震。

关键词: 钻孔联合剖面, 断裂活动性, 雄安新区, 华北平原