3D models of Quaternary-aged sedimentary successions within the Canterbury, New Zealand region

A 3D high-resolution model of the Quaternary geological stratigraphic sequence in the Canterbury, New Zealand region is developed utilising datasets of over 500 high-quality water well logs from a database of 29,985, and over 370 near-surface cone penetration test (CPT) records from a database of 13,670. The model, developed using geostatistical Kriging, represents the complex interbedded regional Quaternary geology by characterising the boundaries between significant interbedded geological formations as 3D surfaces. The model is examined in the form of both geological surface contour maps and vertical cross sections, where the most evident trend identified is the easterly dip caused by the dominant alluvial deposition of terrestrial sediments. The developed 3D interbedded Quaternary stratigraphy model has several applications for hydrologic modelling, earthquake-induced ground motion simulations and seismic site characterisation. For the latter case, the role of the model in constraining surface wave analysis-based shear wave velocity profiling is illustrated.

本研究构建了新西兰坎特伯雷地区第四纪地质地层序列的三维高分辨率模型，所用数据涵盖两部分：一是从29985口水井总数据库中筛选出的500余口优质水文井测井资料，二是源自13670份记录库的370余份近地表圆锥静力触探试验（cone penetration test, CPT）数据。该模型采用地质统计克里金（Kriging）法构建，通过将关键互层地质单元的边界表征为三维曲面，刻画了复杂的区域第四纪互层地质特征。研究通过地质曲面等值线图与垂直剖面两种形式对该模型开展分析验证，其中识别出的最显著构造趋势为受陆相沉积物主流冲积沉积作用控制的东向倾斜。所构建的三维互层第四纪地层模型可应用于水文模拟、地震诱发地面运动模拟以及地震场地特征表征等多个领域。针对地震场地特征表征这一应用场景，本研究阐明了该模型在约束基于面波分析的剪切波速剖面构建中的作用。