Hill MP. 2019. Borehole database for urban geological mapping, southern Auckland area, New Zealand. Lower Hutt (NZ): GNS Science. 34 p. (GNS Science report; 2019/12). doi:10.21420/EZ5W-5K59.
This report documents the results of a compilation of geological information from boreholes in the southern Auckland area as part of GNS Science’s urban geological mapping initiative and for Auckland Council. A total of 34,733 geological records from 2,324 boreholes in the southern Auckland area have been compiled into a digital database. Information in the database also includes geotechnical measurements such as those recorded using the Standard Penetration Test and shear vane methods. The borehole log data were obtained from the New Zealand Geotechnical Database as well as other sources, mainly scans of paper borehole logs. Data compilation focused on the bore drillers’ or geologists’ descriptions of materials encountered during drilling. Lithological interval descriptions were entered verbatim from the borehole records and an interpretation of the geological formation was made from that description. A subjective ranking value is assigned to each borehole to signal the relative quality of the information so that confidence modelling can be applied to 3D and other interpretations of the borehole data. The compiled and interpreted borehole data are currently stored in a Microsoft Access™ database for management and integration of data into Geographic Information System, 3D modelling and other data interpretation software. The database has been designed around GeoSciML (a data model and data transfer standard for geological information) and other data standards as well as formatting standards required by 3D modelling software. The report provides maps illustrating 2D geological information that can be displayed from the borehole database as well as illustrations of preliminary 3D geological models. (auth)