SURVEY OF ANCIENT TOMB-LIKE TOPOGRAPHY IN THE NORTH CAPE OF ORONO-SHIMA ISLAND －ORIGINS OF THE ANCIENT TOMB SYSTEM IN JAPAN?－

Abstract. Orono-shima Island is a remote Island in the Tsushima Strait, it is 4.3km around. Since ancient times, it has been a landmark when crossing from the Korean Peninsula to Japanese archipelago via Tsushima Island and Iki Island. However, large-scale ruins and burial mounds are not known on Orono-shima Island until now. During my four years on the island, the author walked all over the island for terrain survey. As a result, the author discovered a topography like keyhole tomb which is a characteristic Japanese burial mound, on the northern cape of the island. It could be up to 150m in size, one of the largest around Kyusyu Island. There is no burial mound comparable to this on a remote island in Japan. Therefore, we created a 3D image using a drone Laser surveying of this terrain and we compared the results with another keyhole tomb. In addition, we analyzed the image of infrared radiation of Orono-shima Island took by Landsat8. In conclusion, it was speculated that this topography was the prototype of the oldest type of keyhole cairn tomb in Japan. The topography of the northern part of Orono-shima could be regaining the missing link between the cairn on the Korean Peninsula of the first century and the oldest type of keyhole cairn tomb in Japan of the third century.