SEISMOLOGY AND GEOLOGY ›› 2020, Vol. 42 ›› Issue (6): 1417-1431.DOI: 10.3969/j.issn.0253-4967.2020.06.010

• Research paper • Previous Articles     Next Articles


XU Zhi-guo1,2), WANG Jun-cheng1), WANG Zong-chen1), LIANG Shan-shan3), SHI Jian-yu1)   

  1. 1)National Marine Environmental Forecasting Center, Beijing 100081, China;
    2)Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China;
    3)China Earthquake Networks Center, Beijing 100045, China
  • Received:2020-02-26 Revised:2020-08-18 Online:2020-12-20 Published:2021-02-24


徐志国1,2), 王君成1), 王宗辰1), 梁姗姗3),*, 史健宇1)   

  1. 1)国家海洋环境预报中心, 北京 100081;
    2)中国科学院大学, 计算地球动力学重点实验室, 北京 100049;
    3)中国地震台网中心, 北京 100045
  • 通讯作者: * 梁姗姗, 女, 工程师, E-mail:。
  • 作者简介:徐志国, 男, 1979年生, 2007年于中国地震局地球物理研究所获地球探测与信息专业硕士学位, 高级工程师, 主要从事实时地震学与海啸预警预报应用研究, 电话: 010-62105791, E-mail:。
  • 基金资助:
    自然资源部 “全球变化与海气相互作用”(GASI-GEOGE-05)和同济大学海洋地质国家重点实验室开放课题(MGK20204)共同资助

Abstract: A strong earthquake with magnitude MW=7.1 occurred in the area of Molucca Sea, Indonesia on November 14, 2019(Coordinated Universal Time, UTC), and then generated a small-scale local tsunami. In order to better understand the earthquake source characteristics and seismogenic structure, as well as to assess the hazard of tsunami caused by earthquake, this paper mainly focuses on the regional tectonic background, the focal mechanism, and tsunami numerical simulation for the Molucca Sea MW7.1 earthquake. The broadband seismic waveforms from IRIS Data Management Center are used to estimate the moment tensor solution of this earthquake by W phase method. The result shows that the Molucca Sea earthquake occurred at a shallow depth on a high dip-angle, right-lateral reverse fault, the aftershocks were distributed along the SSW-NNE direction and concentrated near the main shock. These results indicate the Molucca Sea earthquake with characteristic of compressional rupture occurred in the complex plate boundary region of eastern Indonesia, which is dominated mostly by the collision interaction of the Halmahera slab and the Sangihe slab in the east and west sides of Molucca Sea under control of current regional stress field. The coseismic displacements of Molucca Sea MW7.1 earthquake calculated using Okada's model of rectangular dislocation in a uniform elastic half-space show that the Molucca Sea earthquake generated vertical coseismic deformation with a maximum uplift of 0.15m when the rupture occurred along the high dip-angle reverse fault. The synthetic tsunami waveforms are provided by COMCOT tsunami modelling package solving the nonlinear shallow water wave equations based on the determined fault geometry from W phase inversion. These studies indicate the vertical coseismic deformation resulting in the sudden uplift of water volume above the earthquake source, and finally inducing a small-scale local tsunami. The energy of tsunami mainly propagates to both side of the fault, and part of energy propagates to Sula Islands of Indonesia along the fault dislocation direction; and compared with the first cycle of tsunami records observed by tide gauges deployed along the coastal line of earthquake source region, the observed tsunami head wave fits well with the synthetic wave, both are consistent in amplitude and tsunami arrival time, but the follow-up waveforms are quite different. The numerical simulation of tsunami shows that, in combination with the fault geometry parameters obtained by W phase fast inversion, the tsunami numerical model can be used for tsunami early warning, and it provides sufficient accuracy for forecasting tsunami wave height, thus, having great practical significance for understanding the propagation process and disaster distribution of tsunami.

Key words: Molucca Sea earthquake, tsunami, arc-arc collision, focal mechanism, numerical simulation

摘要: 2019年11月14日16时17分(UTC), 印尼马鲁古附近海域发生了MW7.1地震, 并引发小规模海啸。 为深入理解和认识该地震的震源参数和发震构造特征, 评估其引发海啸的危险性, 文中初步分析了该地震的区域构造背景、 震源机制以及海啸数值模拟等内容。 W震相快速矩张量解反演结果表明马鲁古海地震是一次浅源、 以高倾角右旋斜向逆冲为主的地震事件, 余震呈SSW-NNE向带状分布, 推测此次地震是在马鲁古海东、 西两侧哈马黑拉弧-桑义赫弧碰撞所产生的区域应力场的作用下发生的以挤压破裂为主的地震事件。 海啸的数值模拟结果表明, 在高倾角发震断层近垂直倾滑的逆冲过程中, 海底地形产生了同震垂直位移, 使得震源上方的水体突然抬升, 从而产生了小规模的局地海啸; 震源周边大部分潮位站记录的海啸首波理论波形和观测波形的到达时间和波形幅度都较为一致, 说明结合W震相反演所得的地震断层面的几何参数能够用于海啸早期预警, 可有效地预测海啸地震产生的海啸波高, 并对于认识海啸成灾过程及灾害分布具有重要的现实意义。

关键词: 马鲁古海地震, 海啸, 弧-弧碰撞, 震源机制, 数值模拟

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