The author is working on developing a technical method to extract the estimated area of mudslide scars such as landslide and debris flow using ΔNDVI images created from optical satellite data (Sentine l―2, Planet) that are frequently taken before and after disasters in areas where landslides have occurred widely both in Japan and overseas. This method can be analyzed and extracted both in Japan and overseas, and the number of locations, individual areas, and total areas of the estimated area of mudslide scar can be easily calculated, so the extraction results can be used to roughly grasp the area.