In April 2001, the Ocean Drilling Program (ODP) Site 1202 operated on the south slope of southern Okinawa Trough, the same position on the northern slope of Ilan Sill. Four holes are cored; the deepest one is 1,275 m under sea level and 410 m below seafloor (mbsf). The drill core of entire 410-m depth takes out from the strata, and makes various kinds of inspection.
The analysis of 410 mbsf terrigenous sediments in the ODP Site 1202 leaks out the sedimentation rate is the biggest one in the world, about 400~500 cm/kyr. According to the global data of the world, the common condition is 3~5 cm/kyr. The sediments at Site 1202 are deposited from low-grade metamorphic schist and marls, which is found within these mountain ranges on the island of Taiwan.
At Site 1202, the nearest river is Lanyang River, which is a clear stream, low in sand, and limited flow. The sediment of Lanyang River does not exceed 1,500,000 m3 every year that indicates it cannot drift enormous sediment of sand and stone continuously to southern Okinawa Trough. It has not been clear where does this district sediment comes from?
From the analysis of the drill core of ODP Site 1202, there are a few volcano glass particle samples in it that shows once nearby the eruption of volcanoes in the north segment of Snow Mountains happened, and little part of the sediment mixed the volcanic ash.
It is the only answer that the volcanoes of northern Snow Mountains have erupted and triggered the big landslide of east hillside that produced the sediments of earth to ODP Site 1202. This big landslide may cause a mega-tsunami that becomes a worldwide cataclysm and the calamity of human.