[M-TT49] 人新世における高精細地形・地球物理データの活用

[MTT49-P05] UAV-SfMおよび航空レーザ測量による広域地形情報の比較：フィリピン・タール火山の例

*早川 裕弌¹、楠本 成寿²、小倉 拓郎^3,5、長尾 年恭⁴、Alanis Paul Karson B. ⁶ (1.北海道大学地球環境科学研究院、2.富山大学理工学研究部 、3.東京大学新領域創成科学研究科、4.東海大学海洋研究所、5.北海道大学環境学院、6.PHIVOLCS (DoST))

キーワード：DEM、ALS、UAV

Frequent acquisition of topographic data for a wide area is fundamental for studies on volcanoes because volcanic activities often cause changes in topography, and other properties, including gravitational anomalies, needs to be calibrated based on the topographic data. Airborne laser scanning (ALS) by a crewed aircraft is a standardized approach to acquire topographic data in a wide area, but its high cost limits its frequent applications. Measurements using an unmanned aerial vehicle (UAV)-based structure-from-motion (SfM) photogrammetry is becoming more popular in recent years for geoscientific studies, but its accuracy is often found to be relatively low particularly if ground control points (GCPs) are unable to be set in the areas of interest. However, the use of low-accuracy data can still be beneficial for some specific research purposes such as geomorphological mapping and gravity mapping. To validate the usefulness of low-accuracy data, we compare ALS-derived and UAV-SfM-derived topographic data of the island of the Taal volcano in the Philippines. Although the UAV-based data shows significant inaccuracies and errors, the data can be instantly obtained at a low cost and is found to be enough for a rough geomorphological mapping and calibration of gravitational data for the wide area. Further assessments and compilation of acceptable resolution and accuracy of various topographic data are encouraged.