有限断层模型在2015年9月16日智利M_w8.3级地震海啸数值模拟中的应用与评估

发布时间：2018-07-11 18:48

本文选题：有限断层 + 数值模拟　；参考：《海洋学报》2017年11期

【摘要】：2015年9月16日22时54分(当地时间)智利中部近岸发生M_w8.3级地震,震源深度25km。同时,强震的破裂区长200km,宽100km,随之产生了中等强度的越洋海啸。海啸影响了智利沿岸近700km的区域,局部地区监测到近5m的海啸波幅和超过13m的海啸爬坡高度。太平洋区域的40多个海啸浮标及200多个近岸潮位观测站详细记录了此次海啸的越洋传播过程,为详细研究此次海啸近场及远场传播及演化规律提供了珍贵的数据。本文选择有限断层模型和自适应网格海啸数值模型建立了既可以兼顾越洋海啸的计算效率又可以实现近场海啸精细化模拟的高分辨率海啸模型。模拟对比分析了海啸的越洋传播特征,结果表明采用所建立的模型可以较好地再现远场及近场海啸特征,特别是对近场海啸的模拟结果非常理想。表明有限断层可以较好地约束近场、特别是局部区域的破裂特征,可为海啸预警提供更加精确的震源信息,结合高分辨率的海啸数值预报模式实现海啸传播特征的精细化预报。本文结合观测数据与数值模拟结果初步分析了海啸波的频散特征及其对模型结果的影响。同时对观测中典型的海啸波特征进行的简要的总结。谱分析结果表明海啸波的能量主要分布在10~50min周期域内。这些波特征提取是现行海啸预警信息中未涉及,但又十分重要的预警参数。进一步对这些波动特征的详细研究将为海啸预警信息及预警产品的完善提供技术支撑。
[Abstract]:At 22:54 (local time) on September 16, 2015, a Mw8.3 earthquake occurred near the central coast of Chile, with a focal depth of 25 km. At the same time, the rupture zone of the strong earthquake is 200 km long and 100 km wide, resulting in a moderately strong transoceanic tsunami. The tsunami affected the area near 700km along the coast of Chile, and the tsunami amplitude of nearly 5m and the height of tsunami climbing more than 13m were observed in some areas. More than 40 tsunami buoys and more than 200 inshore tidal observation stations in the Pacific region have recorded the transoceanic spread of the tsunami in detail, which provides valuable data for the detailed study of the near-field and far-field propagation and evolution of the tsunami. In this paper, the finite fault model and the adaptive grid tsunami numerical model are selected to establish a high-resolution tsunami model, which not only takes into account the computational efficiency of the transoceanic tsunami but also can be used to simulate the near-field tsunami finely. The characteristics of transoceanic tsunami propagation are compared and analyzed. The results show that the proposed model can well reproduce the characteristics of far-field and near-field tsunamis, especially the simulation results of near-field tsunamis are very ideal. The results show that the finite fault can restrain the near field, especially the rupture characteristics of the local area, and can provide more accurate source information for tsunami warning. Combined with the high-resolution numerical tsunami prediction model, the fine prediction of tsunami propagation characteristics can be realized. In this paper, the dispersion characteristics of the tsunami wave and its influence on the model results are preliminarily analyzed by combining the observed data with the numerical simulation results. At the same time, a brief summary of the typical tsunami wave characteristics in the observation is given. The results of spectral analysis show that the energy of tsunami wave is mainly distributed in 10~50min periodic domain. These wave feature extraction is not involved in the current tsunami warning information, but also very important early warning parameters. Further detailed study of these volatility features will provide technical support for the improvement of tsunami warning information and early warning products.
【作者单位】：国家海洋环境预报中心;国家海洋局海啸预警中心;国家海洋环境预报中心海洋灾害预报技术研究国家海洋局重点实验室;
【基金】：海洋公益性行业科研专项项目(201405026,201205034,201305031)
【分类号】：P731.25

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