摘要
古地震事件的识别及其复发周期的准确厘定是古地震研究中的核心问题。然而,由于海水覆盖等原因,发生在海底的地震无法通过探槽等传统方法直接识别,而只能依赖浊积岩和海啸沉积等间接手段进行推断,使得海底古地震事件的识别存在多解性,并对复发周期的估算带来不确定性。本研究以新西兰库克海峡Wairau Fault活动断层为例,基于海底高精度地震剖面,结合地震-沉积演化过程、生长指数以及沉积层坡度变化等,尝试识别海底古地震事件。选取跨断层的L8地震剖面,重新解译并识别出近10 ka以来发生的9次古地震事件,其复发周期为0.4~1.7 ka,平均复发周期约为1.1 ka。这一结果与Wairau Fault陆域地段的古地震事件及复发周期相吻合,验证了海域古地震识别的准确性和可行性,为该断层地震破裂行为特征的研究以及海底古地震研究提供了可靠的案例支持。
The identification of paleoseismic events and the precise determination of recurrence intervals represent key scientific challenges in paleoseismic research.However,due to factors such as seawater coverage,submarine paleoearthquakes cannot be directly detected through trenching and must instead be inferred indirectly via proxies such as turbidites,high-precision seismic profiles,and tsunami deposits,leading to multiple interpretations of identification results and uncertainties in estimating recurrence intervals.This study focused on the active Wairau Fault in the Cook Strait of New Zealand,utilizing high-precision seismic data(specifically the L8 profile)in conjunction with seismic sedimentary evolution,fault growth indices,and sedimentary slope angle variations to identify paleoseismic events on the seafloor along the fault.Using the L8 seismic profile,we reinterpreted the L8 profile and identified 9 paleoearthquake events that occurred over the past 10 ka,with recurrence intervals ranging from 0.4 ka to 1.7 ka and an average of approximately 1.1 ka.These findings are consistent with the paleoearthquake events and recurrence intervals previously reported for the onshore segment of the Wairau Fault,demonstrating the potential accuracy and feasibility of identifying marine paleoearthquakes using this multi-proxy approach and providing a reference case for improving understanding of the seismic rupture characteristics of the fault and advancing the study of seafloor paleoearthquakes.
作者
孙文
周民婷
代向明
李志刚
SUN Wen;ZHOU Minting;DAI Xiangming;LI Zhigang(Guangdong Provincial Key Laboratory of Geodynamics and Geohazards/School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,Guangdong,China)
出处
《大地构造与成矿学》
北大核心
2025年第5期1073-1084,共12页
Geotectonica et Metallogenia
基金
国家重点研发计划项目(2023YFC3008600)
国家自然科学基金项目(42172233)联合资助。
