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Landslide monitoring techniques in the Geological Surveys of Europe
Landslide monitoring is a mandatory step in landslide risk assessment. It requires collecting data on landslide conditions (e.g., areal extent, landslide kinematics, surface topography, hydrogeometeorological parameters, and failure surfaces) from different time periods and at different scales, from site-specific to local, regional, and national, to assess landslide activity. In this analysis, we collected information on landslide monitoring techniques from 17 members of the Earth Observation and Geohazards Expert Group (from EuroGeoSurveys) deployed between 2005 and 2021. We examined the types of the 75 recorded landslides, the landslide techniques, spatial resolution, temporal resolution, status of the technique (operational, non-operational), time of using (before the event, during the event, after the event), and the applicability of the technique in early warning systems. The research does not indicate the accuracy of each technique but, rather, the extent to which Geological Surveys conduct landslide monitoring and the predominant techniques used. Among the types of landslides, earth slides predominate and are mostly monitored by geological and engineering geological mapping. The results showed that Geological Surveys mostly utilized more traditional monitoring techniques since they have a broad mandate to collect geological data. In addition, this paper provides new insights into the role of the Geological Surveys on landslide monitoring in Europe and contributes to landslide risk reduction initiatives and commitments (e.g., the Kyoto Landslide Commitment 2020).
Journal Article
A semi-automatic method for 3D modeling and visualizing complex geological bodies
The technology of 3D geological modeling is a powerful tool for representing the geological structures and subsurface strata distribution, which can effectively assist in the geological interpretation and analysis work. However, most existing modeling methods usually need the supports of professional geological modeling software. These systems often have tedious data preprocessing, complex modeling and visualization processes, and non-professionals have difficulty mastering them in a short time. In order to improve the operability and intuitiveness for 3D geological modeling and visualization, this paper proposes a semi-automatic method for 3D modeling and visualizing complex geological bodies by combining typical GIS systems and 3D modeling software such as ArcGIS and SketchUp. First, the Python object-oriented program language and Arcpy package are combined for preprocessing borehole data automatically. Next, the multiple 3D analysis and file conversion tools of Arctoolbox and ModelBuilder are combined for constructing a model to generate strata interfaces. Then, the makefaces and Boolean plug-ins of SketchUp are combined for semi-automatically constructing the 3D model of complex geological bodies and implementing various forms of visualization. Last, the borehole data and geological maps acquired from the geological survey are used for testing our modeling method. The modeling processes and results show that the method can quickly construct the 3D model of complex geological bodies with very complex geological structures such as missing strata, faults and lenses. This paper shows the simplicity and practicality of the proposed method for modeling and visualizing complex geological bodies.
Journal Article
Integrated framework for geological modeling: integration of data, knowledge, and methods
Three-dimensional (3D) geological modeling from limited and scattered information is essential for engineering geological investigation and design. Previous studies have encountered limitations when using a single modeling approach in complex tasks involving diverse geological structures, due to difficulties in accommodating the heterogeneity of geological structures and data imbalances. In response to this situation, this work presented an integrated geological modeling framework enabling the fusion of multi-source data, the integration of data and knowledge, and the combination of multiple modeling methods. Initially, multi-source data were merged into a unified format and integrated with knowledge extracted from geological texts to create a geological knowledge graph and a geospatial database for modeling. The complexity of the geological setting was then quantified by constructing a joint influence function, which informed the division of the modeling area into several subregions with geological significance. According to the geological characteristics and data conditions, the appropriate method for each subregion was automatically matched for independent modeling and finally integrated into a complete 3D geological model. The results indicated that the proposed integrated framework provided a flexible solution for complex modeling tasks, simplifying the process by addressing simpler subtasks while retaining the ability to capture structural information in geological domains with diverse characteristics. Moreover, the integration of geological data and knowledge promoted the structured representation and utilization of geological knowledge, promising to provide richer information for model construction and validation. This is crucial for the developed model to be able to effectively support engineering geological exploration.
Journal Article
Basic geological mapping / Richard J. Lisle, Peter J. Brabham, and John W. Barnes
\"Basic Geological Mapping, 5th Edition is an essential basic guide to field techniques in mapping geology\"-- Provided by publisher.
Book
Geological Mapping Using Drone-Based Photogrammetry: An Application for Exploration of Vein-Type Cu Mineralization
In this research, drone-based photogrammetry was utilized for mapping geology with the objective of mineral exploration in the Shahzadeh Abbas Cu deposit, Kerman province, Iran. Cu mineralization is of vein-type and follows geological structures. A low-cost drone was used to collect geological data. A spatial resolution of 3.26 cm was achieved by considering a flight altitude of 70 m. To reach the accuracy of less than 5 cm, 70% lateral and 80% front image overlaps were applied and 220 temporary ground control points (TGCPs) were used in an area of 2.02 km2. TGCPs were accurately positioned using DGPS-RTK measurements. Agisoft PhotoScan software was used for photogrammetric processing. The orthophoto product was performed for outlining geological units through visual interpretation. The digital elevation model (DEM) was converted to a hill-shade model in ArcGIS software to extract the geological structures such as faults and dikes. A draft geology map was prepared using orthophoto and hill-shade images to minimize the time and cost of the subsequent field work. Rock sampling was carried out and Cu-bearing veins were specified through field investigations. The geology map was finalized based on field work data and petrology studies. The geological survey indicated that diabase dikes with a northwest–southeast strike often host Cu mineralization in the study area. The position of Cu-bearing dikes was delineated for the next stage of the exploration program. This research demonstrated the time- and cost-effectiveness of using drone-based photogrammetry for preparing base geology maps for the exploration of vein-type mineralization in far districts with rough topography.
Journal Article
Engineering Geological Mapping for the Preservation of Ancient Underground Quarries via a VR Application
Underground monument preservation is tightly linked to geological risk. The geological risk management of underground structures typically relies on a preliminary site investigation phase. Engineering geological mapping—as a key site investigation element—is largely based on manual in situ work, often in harsh and dangerous environments. However, although new technologies can, in many cases, decrease the on-field time as well as eliminate inaccessibility issues, the example presented in this study demonstrates a special challenge that had to be addressed. The ancient underground marble quarries of Paros Island in Greece constitute a gallery complex of a total length of 7 km and only two portals, resulting in total darkness throughout almost the full length of the unsurveyed galleries. As such, the entire survey and engineering geological mapping solely relied on a virtual reality application that was developed based on a digital replica of the quarries using laser scanning. The study identifies several critical locations with potentially unstable geologic structures and computes their geometrical properties. Further numerical analyses based on data extracted directly from the digital replica of the rock mass led to the definition of appropriate risk mitigation measures along the underground marble quarries.
Journal Article