Earth Science Frontiers ›› 2022, Vol. 29 ›› Issue (5): 203-215.DOI: 10.13745/j.esf.sf.2021.9.13

Previous Articles     Next Articles

Focal mechanism solutions for global tsunami earthquakes and future tsunami threat to China

JIA Zhongjia1,2(), ZHU Junjiang1,2,*(), OU Xiaolin1,2, ZHANG Shengsheng1,2, HUANG Chang1,2, CHEN Ruixue1,2, ZHANG Shaoyu1,2, LI Sanzhong1,2, JIA Yonggang3,4, LIU Yongjiang1,2   

  1. 1. Institute for Advanced Ocean Study and College of Marine Geosciences/Frontiers Science Center for Deep Ocean Multispheres and Earth System/MOE Key Lab of Submarine Geosciences and Prospecting Techniques, Ocean University of China, Qingdao 266100, China
    2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266100, China
    3. Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (MEGE), Ocean University of China,Qingdao 266100,China
    4. Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266100, China
  • Received:2021-05-16 Revised:2021-09-02 Online:2022-09-25 Published:2022-08-24
  • Contact: ZHU Junjiang


Tsunamis are one of the five major marine natural disasters that can seriously threaten human life and property. In recent years international researchers have conducted a large number of studies on earthquake-induced tsunamis. These studies mainly focused on numerical simulation of tsunami generation, propagation, climb and inundation, as well as on paleo-tsunami sediments, but lacked attention to the focal mechanism of tsunami earthquakes, especially of those below magnitude 6.5. As revealed by the most recent studies in China on earthquake-induced tsunamis, tsunami hazards caused by earthquakes of magnitude less than 6.5 cannot be ignored. In this paper, 766 global earthquake-generated tsunamis are summarized; focal mechanism solutions for tsunami earthquakes are classified using triangulation techniques; and focal mechanism solutions for 341 tsunami earthquakes (since 1976) are analyzed in detail, with 633 wave heights analyzed by statistical methods. As results show, all types of earthquakes—strike-slip, normal and thrust earthquakes as well as unusual earthquakes—can cause tsunamis; whilst most tsunamis are caused by thrust fault earthquakes, and tsunami earthquakes below magnitude 6.5 can produce tsunami wave height up to 10 m to cause major damages. Mechanistically, thrust and normal earthquakes as well as unusual earthquakes can directly cause vertical changes in submarine topography to generate tsunamis; whereas strike-slip earthquakes can cause tsunamis for one of two reasons: they are not pure strike-slip type but have normal/thrust component, or they trigger submarine landslide to cause changes in seabed topography in generating tsunamis. According to focal depth analysis, more than 97% of tsunami earthquakes are shallow earthquakes less than 30 km deep, but intermediate and deep earthquakes can also cause tsunamis. Based on seismic source characteristics, geographical location of China mainland, as well as historical occurrences of tsunamis, we propose that earthquake-induced tsunamis that may threaten China's coastal areas in the future are concentrated in the Manila trench and Taiwan strait. These areas should be monitored closely and early warning systems should be established to reduce disaster damage.

Key words: tsunami earthquake, focal mechanism solution, tsunami wave height, tsunami origin

CLC Number: