基于震级上限估计的渤海海啸危险性与共振特征研究

Research on local tsunami hazard and resonance characteristics in the Bohai Sea based on magnitude ceiling estimation

中文关键词:  震级上限  渤海  海啸  危险性  海啸共振

英文关键词:magnitude ceiling  Bohai Sea  tsunami  hazard  resonance of tsunami waves

中文摘要:

      根据渤海区域地质断层特征和历史地震活动规律，分析得出渤海内潜在最大震级上限为8.1级，并对该海啸源可能的两组震源机制分别进行了数值模拟。模拟结果显示：渤海局部区域海啸波幅最大可达 1.5 m，最大流速可达2.8~3.0 m/s，具备造成灾害损失的风险。在该海啸源情景下，渤海海盆内易激发长期的水位自由振荡，部分区域水位振荡可持续 20 h以上，振荡波幅的大小与海啸首波波幅相当或更大。基于快速傅里叶变换方法对海啸波进行频谱分析，部分长周期频谱成分满足区域固有共振特征。因此，渤海内一旦发生海啸，不仅要关注海啸首波可能造成的灾害性影响，还要密切关注海啸首波到达后，可能产生的长时间、长周期的海啸波共振以及往复式海啸流造成的影响。

英文摘要:

      Based on the faults and historical earthquakes data of the Bohai Sea, the parameters of potential earthquakes are confirmed and simulated. According to the numerical simulation results, under the influence of local tsunami, the maximum tsunami amplitude in the Bohai Sea could reach 1.5m, and the maximum velocity is 2.8~3.0m/s. The resonance of tsunami waves could happen in the Bohai Sea, and long period waves at some output points can last over 20 hours, which has a comparable or even bigger amplitude to that of a tsunami head wave. Spectrum analysis based on the fast Fourier transform method also showed the characteristics of tsunami wave resonance. According to our research, once a local tsunami occurs in the Bohai Sea, besides the tsunami head wave, the influence of long period and lasting resonance of tusnami waves should be concerned to assess the hazard of local tsunami.