Imaging active faulting in the western Taiwan Strait

Yifeng Zhang,Andrew Tien-Shun Lin,Xing Jin,Zhizhao Xie,Joaquina Alvarez-Marron,Hao Kuo-Chen,Dennis Brown

doi:10.1038/s41598-020-60666-3

Yifeng Zhang, Andrew Tien-Shun Lin + Show 5 more

Open Access

https://doi.org/10.1038/s41598-020-60666-3

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Abstract

Large, destructive historical earthquakes off the coast of China’s Fujian Province point to important tectonic activity in the western Taiwan Strait that, until recently, has received little attention. We present newly acquired reflection seismic data that is used to study the shallow crustal structure of the western Taiwan Strait. With these data we map the location of the Benhai fault for the first time, describe its upper crustal geometry and, in combination with seismicity and earthquake focal mechanisms, interpret its kinematics. These new data demonstrate that there is wide spread evidence of faulting that reaches the sea floor in the western Taiwan Strait, clearly indicating that the Benhai fault is active. Faults that cut up section from steep basin sidewalls to form flower structures or terraced sidewall fault zones, together with the fault and basin map pattern, are consistent with this fault zone being in the early developmental stages of a dextral strike-slip system. Earthquake focal mechanisms, although not definitive, support the model of an active dextral strike-slip fault system in the western Taiwan Strait.

Highlights

Large, destructive historical earthquakes off the coast of China’s Fujian Province point to important tectonic activity in the western Taiwan Strait that, until recently, has received little attention
Despite a number of large, destructive historical earthquakes having occurred in the western Taiwan Strait (Fig. 1), little is known about its geological structure or the potential risk that this area could pose for people and infrastructure along the coast of China’s Fujian Province
The western Taiwan Strait has been typically shown on maps as tectonically quiescent, with often little more interpretation than the presence of rift-related Paleogene basins[3,6,24,29] or, at the most, with strike-slip faults on land along the coast of Fujian Province[2,4,30]

Summary

Introduction

Destructive historical earthquakes off the coast of China’s Fujian Province point to important tectonic activity in the western Taiwan Strait that, until recently, has received little attention. Despite a number of large, destructive historical earthquakes having occurred in the western Taiwan Strait (Fig. 1) (see Methodology for the data base of historical events used in this study), little is known about its geological structure or the potential risk that this area could pose for people and infrastructure along the coast of China’s Fujian Province In large part, this paucity of knowledge is because little geoscientific attention has focused on the Taiwan Strait since the 1970’s and 1980’s when extensive reflection seismic and drilling campaigns[1,2,3] failed to identify significant petroleum potential. We use newly acquired reflection seismic data in the western Taiwan Strait (Fig. 1) to accurately map the location of the Benhai fault for the first time, to ascertain its upper crustal geometry and, in combination with seismicity and earthquake focal mechanisms, to determine its kinematics

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Conclusion