Digital elevation model (DEM) have been indispensable data for identifying fault traces and measuring the amount of recent faulting. However, some of DEM produced by Air-borne / Terrestrial Light Detection and Ranging (LiDAR) are difficult to observe the tectonic geomorphology because of artificial modification, or because its density is too sparse. In this paper, we attempt to construct DSM by using SfM (Structure from Motion) - MVS (Multi-Video Stereo) with aerial photographs. We used old aerial photographs before artificially modified in Awa city, as well as aerial photographs by the 7-m-high pole camera (Hi-view) in Shikokuchuo city along the Median Tectonic Line active fault system in Shikoku, Southeast Japan.
As a result, the 0.5m-mesh DSM and 0.05m-mesh DSM were generated from old aerial photographs scaled 1 to 8,000 and Hi-view photographs by compact digital camera, respectively. The relative height of the fault scarp based on the 0.5m-mesh DSM is almost same as that based on the 5m-mesh DEM of Geospatial Information Authority of Japan and 1m-mesh DEM of aerial photograph survey company. On the other hand, the shape of dense points based on the 0.05m-mesh DSM along the line is quite similar to the topographic profile based on the measurement by conventional total station method. These cases illustrate that SfM- MVS photogrammetry with Old / Hi-view aerial photography is quite useful new method for studying active tectonic geomorphology.
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