考虑区域地质构造特征的概率性海啸灾害评估

Probabilistic tsunami hazard assessment considering the characteristics of regional geological structures

确定性海啸灾害评估通常考虑极端情况下的海啸灾害情况,而考虑到实际地震海啸发生时各种参数的不确定性,概率性海啸灾害评估(Probabilistic Tsunami Hazard Assessment,PTHA)可以给出某个地区海啸波高的概率分布,逐渐成为目前的研究热点。现有的PTHA研究中通常假设地震震源在空间上是均匀分布的。而实际地震的发生位置受到岩石属性和板块应力等地质构造特征的影响,通常是不均匀的。该文以马尼拉俯冲带为例,构造了震源空间位置的非均匀分布模型,对中国沿海地区在未来2000年内遭受的海啸灾害进行概率性评估。结果显示,非均匀分布模型得到的海啸波高的超越概率相比均匀模型差异最高可达20%。因此,考虑地震位置空间分布的不均匀性对PTHA的研究有重要影响。

Deterministic tsunami hazard assessment is generally used to evaluate tsunami hazards of worst scenarios.Due to large uncertainties of earthquake parameters in real events,Probabilistic Tsunami Hazard Assessment(PTHA)is now widely adopted to derive the probability of tsunami waves in coastal areas.Current PTHA research generally assumes that earthquake locations are uniformly distributed in space.However,influenced by various geological factors,such as rock properties,plate stress,etc.,earthquake locations are not uniform in space in reality.In this paper,a probabilistic model of earthquake Locations is proposed by taking the Manila subduction zone as an example,and the probability of tsunami waves along the Chinese coastline is derived.Results show that the exceeding probability of tsunami waves can differ as much as 20%for uniform and non-uniform earthquakes locations.Thus,it is important to consider the probability m odel of earthquake locations in future PTHA studies.