• Journal of the Korean Geophysical Society
• /
• v.2 no.1
• /
• pp.9-26
• /
• 1999

The Ulleung Basin (Tsushima Basin) in the southwestern East Sea (Japan Sea) is floored by a crust whose affinity is not known whether oceanic or thinned continental. This ambiguity resulted in unconstrained mechanisms of basin evolution. The present work attempts to define the nature of the crust of the Ulleung Basin and its tectonic evolution using seismic wide-angle reflection and refraction data recorded on ocean bottom seismometers (OBSs). Although the thickness of (10 km) of the crust is greater than typical oceanic crust, tau-p analysis of OBS data and forward modeling by 2-D ray tracing suggest that it is oceanic in character: (1) the crust consists of laterally consistent upper and lower layers that are typical of oceanic layers 2 and 3 in seismic velocity and gradient distribution and (2) layer 2C, the transition between layer 2 and layer 3 in oceanic crust, is manifested by a continuous velocity increase from 5.7 to 6.3 km/s over the thickness interval of about 1 km between the upper and lower layers. Therefore it is not likely that the Ulleung Basin was formed by the crustal extension of the southwestern Japan Arc where crustal structure is typically continental. Instead, the thickness of the crust and its velocity structure suggest that the Ulleung Basin was formed by seafloor spreading in a region of hotter than normal mantle surrounding a distant mantle plume, not directly above the core of the plume. It seems that the mantle plume was located in northeast China. This suggestion is consistent with geochemical data that indicate the influence of a mantle plume on the production of volcanic rocks in and around the Ulleung Basin. Thus we propose that the opening models of the southwestern East Sea should incorporate seafloor spreading and the influence of a mantle plume rather than the extension of the crust of the Japan Arc.

• Journal of the Daesoon Academy of Sciences
• /
• v.43
• /
• pp.103-137
• /
• 2022

In religious symbology, an emblem is a symbolic mark, which differentiates a religion from other groups. In addition, it holds a symbolic or conceptual character that enables viewers to recognize a certain religion. Daesoon Jinrihoe, a representative order among Korean religious traditions, also has a symbolic mark; however, it has not been designated with an official name as symbol despite its usage dating back to May 11, 1978. At the time, that mark has served as an emblem. Afterwards, the emblem was printed and has been officially used as a flag (unofficially known as the Dao Flag, the Fellowship Flag, etc.) since October 20th of that same year. The emblem of Daesoon Jinrihoe which is not only printed in the flag but has been utilized as a symbolic mark representing the order. Nevertheless, it is hard to find research related to this symbol. Consequently, this study aims to apprehend the existing materials about the flag's emblem and its meaning, as well as attempt to interpret its various implications. Indeed, this work will suggest another point of view about the emblem given that it embraces ambiguity. This research suggests that the emblem symbolically depicts the Daesoon (Great Itineration), Samwon (三圓, Three Circles), Sadae (四大, Four Dae), and the Center, and that, all together, this can imply more profound meanings than were expressed in previously posited explanations. As such, this study draws further significance from Daesoon Thought and find: first, the circle in the center of the emblem signifies the pivot of Daesoon; not just the earthly circle (地圓) or the human circle (人圓). This opens up the possibility that the circle symbolizes Mugeuk (Limitlessness) and Taegeuk (Great Ultimate), which include the pivot of Heaven, Earth, and Humanity. Secondly, the symbol of soil (土) in the center is separated from the human circle and reveals the symbol of harmony and creation as the rod shape of Four Dae. Thirdly, the protuberances in the circle point to specific directions and this allows for additional layers of meaning.