In this study, we present the results from the microzonation study conducted in Port of Spain (PoS), capital of the Republic of Trinidad & Tobago. A dense grid of single-site recordings was used to determine the fundamental frequency of soil above bedrock, while a grid of 26 array recordings comprised the database for finding the 1-D shear wave velocity, with depth. The resonant frequency was found to range from <1.0 Hz, for the deeper sediments to the south, near the coast, to above 4.0 Hz, on the northern outskirts of the city, closer to the rock formations. The array data processing revealed a shear wave velocity less than 360 m s^–1, for the alluvial deposits, whilst for the harder formations, the velocity was at least 1000 m s^–1. To validate the results, a parametric investigation, using synthetic seismograms of ambient noise for simplified 1-D models of the PoS basin sediments, was conducted. A 3-D geological model of the basin was developed, by integrating the experimental results with the simulated data. The model suggests a gradual increase, from north to south, in sediment depth down to ∼160 m. In order to understand and explain the variation of the resonance frequency, a review of the historical development of the area, for the past 250 yr, revealed large-scale, non-engineered land reclamation in the 19th and 20th centuries, resulting in areas with anomalously high amplification of seismic motion.

中文翻译：

---

特立尼达和多巴哥微区划项目：西班牙港口

在这项研究中，我们介绍了在特立尼达和多巴哥共和国首都西班牙港（PoS）进行的微区研究的结果。单站点记录的密集网格用于确定基岩上方土壤的基本频率，而26个阵列记录的网格则包含用于查找一维剪切波速度和深度的数据库。对于较深的沉积物，在靠近海岸的南部，共振频率的范围为<1.0 Hz，而在城市北部郊区，更接近岩层的共振频率为4.0 Hz以上。阵列数据处理显示，冲积沉积物的剪切波速度小于360 m s ^–1，而较硬地层的剪切波速度至少为1000 m s ^–1。为了验证结果，进行了参数研究，使用环境噪声的合成地震图对PoS盆地沉积物的简化一维模型进行了研究。通过将实验结果与模拟数据相结合，开发了盆地的3-D地质模型。该模型表明，沉积物深度从北向南逐渐增加，直至约160 m。为了理解和解释共振频率的变化，回顾该地区过去250年的历史发展，发现了19世纪和20世纪的大规模非工程开垦土地，导致该地区地震运动异常高的放大。