Method for extracting the source of falling rock from microtopography highlight map created by high-density aerial laser data

Koki Sakita, Satoshi Nishiyama, Masashi Miyashita, Yuzo Ohnishi

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    2 Citations (Scopus)

    Abstract

    In order to conduct disaster-prevention inspections without overlooking falling-rock sources, in this paper, we aim to establish a disaster-prevention inspection method using microtopography highlight maps and verify its effectiveness. First, we create the map using the data obtained from a high-density aerial laser. In our study, measurements were carried out using a measurement helicopter loaded with a laser measuring machine capable of irradiating 80,000 to 400,000 points per second. For creating a microtopographical representation, grid data, contour maps, inclination-amount diagrams that calculate the amount of inclination for each grid datum and change the lightness accordingly to express the topography, and wavelet-analysis diagrams that emphasize the change in the unevenness through wavelet analysis, are generally used. However, it is difficult to extract sources of falling rocks, because it is impossible to express the topographic change point between the contour lines in a contour map. It is also difficult to distinguish between ridges and valleys in the inclination-amount diagram because there is no information indicating the height difference. Furthermore, it is difficult to distinguish the microtopography in the wavelet-analysis diagram, because there is no information indicating the height difference or inclination. Therefore, in this study, we created a microtopography highlight map by overlaying 50 cm of grid data, the inclination-amount map, contour diagram, and wavelet-analysis diagram created from the measured laser data. A field survey verified that, by using this map, it was possible to detect a steep cliff of height 2 m or more, which is a possible source of falling rocks. In our study, we were able to extract sources of falling rocks from a microtopography highlight map.

    Original languageEnglish
    Title of host publicationISRM International Symposium - 10th Asian Rock Mechanics Symposium, ARMS 2018
    PublisherInternational Society for Rock Mechanics
    ISBN (Electronic)9789811190032
    Publication statusPublished - Jan 1 2018
    Event10th Asian Rock Mechanics Symposium, ARMS 2018 - Singapore, Singapore
    Duration: Oct 29 2018Nov 3 2018

    Publication series

    NameISRM International Symposium - 10th Asian Rock Mechanics Symposium, ARMS 2018

    Conference

    Conference10th Asian Rock Mechanics Symposium, ARMS 2018
    Country/TerritorySingapore
    CitySingapore
    Period10/29/1811/3/18

    Keywords

    • Aerial Laser Surveying
    • Falling-Rock Source Extraction
    • Steep Cliff

    ASJC Scopus subject areas

    • Geochemistry and Petrology
    • Geophysics

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