• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.174-193
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• 2023

Korea is surrounded by the sea and has rivers connecting to it throughout the inland areas, which has been a geographical characteristic since ancient times. As a result, there have been exchanges and conflicts with various countries through the sea, and rivers have facilitated the transportation of ships carrying grain, goods paid for by taxes, and passengers. Since the past, the sea and rivers have had a significant impact on the lives of Koreans. Consequently, it is expected that there are many cultural heritages submerged in the sea and rivers, and continuous efforts are being made to discover and preserve them. Underwater cultural heritage is difficult to discover due to its location in the sea or rivers, making direct visual observation and exploration challenging. To overcome these limitations, various geophysical survey techniques are employed. Geophysical survey methods utilize the physical properties of elastic waves, including their reflection and refraction, to conduct surveys such as bathymetry, underwater topography and strata. These techniques detect the physical characteristics of underwater objects and seafloor formation in the underwater environment, analyze differences, and identify underwater cultural heritage located on or buried in the seabed. Bathymetry uses an echo sounder, and an underwater topography survey uses a side-scan sonar to find underwater artifacts lying on or partially exposed to the seabed, and a marine shallow strata survey uses a sub-bottom profiler to find underwater heritages buried in the seabed. However, the underwater cultural heritage discovered in domestic waters thus far has largely been accidental findings by fishermen, divers, or octopus hunters. This study aims to analyze and summarize the latest research trends in equipment used for underwater cultural heritage exploration, including bathymetric surveys, underwater topography surveys and strata surveys. The goal is to contribute to research on underwater cultural heritage investigation in the domestic context.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.80-87
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• 2011

Autonomous underwater vehicles (AUVs) present the important advantage of being able to approach the seafloor more closely than surface vessel surveys can. To collect bathymetric data, bottom material information, and sub-surface images, multibeam echosounder, sidescan sonar (SSS) and subbottom profiler (SBP) equipment mounted on an AUV are powerful tools. The 3000m class AUV URASHIMA was developed by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). After finishing the engineering development and examination phase of a fuel-cell system used for the vehicle's power supply system, a renovated lithium-ion battery power system was installed in URASHIMA. The AUV was redeployed from its prior engineering tasks to scientific use. Various scientific instruments were loaded on the vehicle, and experimental dives for science-oriented missions conducted from 2006. During the experimental cruise of 2007, high-resolution acoustic images were obtained by SSS and SBP on the URASHIMA around the northern Kumano Basin off Japan's Kii Peninsula. The map of backscatter intensity data revealed many debris objects, and SBP images revealed the subsurface structure around the north-eastern end of our study area. These features suggest a structure related to the formation of the latest submarine fan. However, a strong reflection layer exists below ~20 ms below the seafloor in the south-western area, which we interpret as a denudation feature, now covered with younger surface sediments. We continue to improve the vehicle's performance, and expect that many fruitful results will be obtained using URASHIMA.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.201-216
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• 2013

Ground penetrating radar (GPR) surveys were conducted in a sand tank model in a laboratory and at an alluvial field site to detect the groundwater table and to investigate the influence of saturation on GPR response in the unsaturated zone. In the sand tank model, the groundwater table and saturation in the sand layer were altered by injecting water, which was then drained by a valve inserted into the bottom of the tank. GPR vertical reflection profile (VRP) data were obtained in the sand tank model for rising and lowering of the groundwater table to estimate the groundwater table and saturation. Results of the lab-scale model provide information on the sensitivity of GPR signals to changes in the water content and in the groundwater table. GPR wave velocities in the vadose zone are controlled mainly by variations in water content (increased travel time is interpreted as an increase in saturation). At the field site, VRP data were collected to a depth of 220 m to estimate the groundwater table at an alluvial site near the Nakdong river at Iryong-ri, Haman-gun, South Korea. Results of the field survey indicate that under saturated conditions, the first reflector of the GPR is indicative of the capillary fringe and not the actual groundwater table. To measure the groundwater table more accurately, we performed a GPR survey using the common mid-point (CMP) method in the vicinity of well-3, and sunk a well to check the groundwater table. The resultant CMP data revealed reflective events from the capillary fringe and groundwater table showing hyperbolic patterns. The normal moveout correction was applied to evaluate the velocity of the GPR, which improved the accuracy of saturation and groundwater table information at depth. The GPR results show that the saturation information, including the groundwater table, is useful in assessing the hydrogeologic properties of the vadose zone in the field.

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

• (The) Research of the performance art and culture
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• no.20
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• pp.163-204
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• 2010

"Nectar of Immortality", also known as Suryukwha, is a painting which is hung on the wall during Suryukjae, a rite to console the spirits residing on both land and water. The Suryukwha at Bonyung Temple in the Ming Dynasty consisted of 139 scrolls depicting separate scenes. In Korea, however, Nectar of Immortality combines all the scenes into one large painting. The lower part of Nectar of Immortality describes pain, disasters, and the frailty of human life in this world. This is intended to inspire people to embrace Buddhism and be delivered from their worldly existence. However, it reflects the social realities of that time as well. The scenes at the bottom of the painting of nomadic troupes of entertainers and their performances are part of this reflection. In this section, various scenes of traditional Korean performance are illustrated, such as double and single tightrope walking, Sotdaetagi (performing atop a pole), Ssangjulbaegi (one form of Sotdaetagi), tumbling, bell juggling, mask dramas, dish spinning, puppet shows, the dance of Sadang, and sword dancing. Among these performances, some, such as Sotdaetagi, Ssangjulbaegi, double tightrope walking, bell juggling and sword dancing (Punggakjaengipae), have since ceased to exist. The troupes of entertainers depicted in Nectar of Immortality are Sadangpae, Namsadangpae, Sotdaejaengipae, Choranipae, Punggakjaenipae, Gutjungpae, and circus troupes. When, after itinerant lives, these entertainers die, they become forlorn wandering spirits with no descendants to perform their memorial services. The entertainers in the performance scenes are the embodiment of souls who are the subjects of salvation through Suryukjae. Among these entertainers, Sotdaejaengipae, Sadangpae, Choranipae, Punggakjaenipae and Gutjungpae no longer exist. In sum, Nectar of Immortality provides insight into the vanished content of numerous historic forms of performance and the activities of nomadic troupes of entertainers.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.242-261
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• 2021

Sangjeong was a sculptor-monk who was active in the mid-to-late 18th Century, and the current study established the overall chronology of Sangjeong's Buddhist statues and their styles based on the six sculptures of Sangjeong already known and the Wooden Seated Buddha of 1767 in Songgyesa Temple, Geochang, which was found to be his last work. All of the Buddhist statues of Sangjeong have commonalities in terms of the appearance of the ears, wrinkles on clothing on the upper and lower body, position of hands, and expression of the lower body. The expression of the lower body, in particular, is classified into three types: Type A, where the clothing drapes through the lotus leaves on the bottom; Type B, with an 'S-shaped' drape over the lower body but no lotus leaves or pedestal; and Type C, with the Buddha and pedestal as a single unit, and the clothing draping through the lotus leaves on the pedestal. It appears that Sangjeong faithfully succeeded the style of Taewon, who was his only instructor for sculpture. This is verified based on the records of his participation in the creation of the Wooden Seated Sakyamuni Buddha Triad and Statue of Arhat in Bongeunsa Temple, Seoul, as the third sculptor-monk out of twelve sculptor-monks, and the reflection of the S-shaped drape on the lower body found on the statue of Buddha in Bongeunsa Temple on all of the statues created by Sangjeong. Not only that, but it was assumed that the expression of the pedestal and hair was also inherited by Sangjeong from Taewon and Jinyeol, who was a sculptor-monk from the early 18th Century. The work of Sangjeong and Taewon showed differences in the volume and thickness of statues, strength of unevenness on the wrinkles of clothing, drapes on the right side of chest, and details of the ears. The current study identified the original styles of each individual sculptor and attempted to categorize the fourteen pieces of ten Buddhist statues reflecting the styles of Sangjeong into Sangjeong-style or Taewon-style.