https://repository.kopri.re.kr/handle/201206/5500 Tue, 21 Apr 2026 07:07:31 GMT 2026-04-21T07:07:31Z https://repository.kopri.re.kr/handle/201206/5715 Title: Depositional facies, architecture and environments of the Sihwa Formation Authors: Kim, S. B.; Kim, Y. -G.; Jo, H. R.; Jeong, K. S.; Chough, S. K. Abstract: This paper presents detailed facies and architectural analyses and palaeoenvironmental reconstruction of the Sihwa Formation (Lower Cretaceous), mid-west Korea, which comprises an about 3-km-thick non-marine succession containing abundant dinosaur eggshells. Based on constituent facies, bedset geometry, stacking pattern, and bounding surface characteristics, the entire succession can be classified into three architectural elements. Element I occurs along the basin margin and shows a monotonous stacking of tabular or crudely stratified conglomeratic units. It represents alluvial-fan deposits of debrisflow- dominated fan and sheetflood-dominated fan. Element II is characterized by multi-storey, sheet or upward-widening, conglomeratic channel-fills whose maximum thickness exceeds 1.5 m. Each channelfill unit is encased within red？brown silty sandstones of Element III with sharp erosional bases but diffuse gradational upper boundaries. It consists generally of (1) cut-and-fill deposit (trough crossstratified or openwork conglomerate) in the lower part and (2) composite low-relief bar deposit (lenticular conglomerate and stratified gravelly sandstone) in the upper part. Shallowness of each cutand- fill unit, absence of fining-upward lateral accretion package and the predominance of simple-bar deposit collectively suggest deposition from ephemeral braided streams. Element III typically shows a fining-upward stacking of (1) single- or multi-storey small-scale ( Thu, 01 Jan 2009 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5715 2009-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/5839 Title: Propagators and Feynman diagrams for laterally heterogeneous elastic media Authors: Robert I. Odom; Park, Minkyu Abstract: The propagator for coupled-mode elastic waves can be cast into a number of different representations, which emphasize particular aspects of the wave propagation in a laterally heterogeneous medium. One representation has the form of a generalized scattering operator and contains a quantity that can be interpreted as the lateral impedance. Another representation reduces naturally to the JWKB approximation for smoothly varying media with no mode coupling. The propagator solution for the fields in a laterally heterogeneous elastic medium with weak random boundary fluctuations leads naturally to the application of Feynman diagram techniques for the derivation of Dyson's equation and the Bethe-Salpeter equation for the propagator mean and covariance, respectively. The diagram techniques are reviewed and their utility for solution of random media elastic wave problems is demonstrated. Sat, 01 Jan 2005 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5839 2005-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/5623 Title: Hydroacoustic records and a numerical records of the source mechanism from the first historical eruption of Anatahan Volcano, Mariana Islands Authors: Robert P. Dziak; H. Matsumoto; Byun, S-K.; Park, Minkyu Abstract: Anatahan Volcano in the Commonwealth of the Northern Mariana Islands (CNMI) erupted for the first time in recorded history on 10 May 2003. The underwater acoustic records (T-waves) of earthquakes, explosions, and tremor produced during the eruption were recorded on a sound-channel hydrophone deployed in February 2003. Acoustic propagation models show the seismic to acoustic conversion at Anatahan is particularly efficient, aided by the upward slope of the seamount toward the hydrophone. The hydrophone records confirm the onset of earthquake activity between 0100-0200Z on 10 May, with a substantial increase in seismicity beginning at ~0620Z. In addition, the onset of continuous, low-frequency (3-40 Hz) acoustic energy that is likely volcanic tremor related to magma intrusion was also observed at 0620Z. The hydrophone recorded 1401 earthquakes during the first 3 days of the eruption. A histogram of seismicity indicates two main periods of explosion/eruption activity, the first beginning at ~0620Z on 10 May and the second at ~0000Z on 11 May. Relative earthquake depth estimates indicate both eruption periods were accompanied by earthquake activity from deep within the Anatahan volcanic edifice. A numerical representation of the Anatahan volcano-seismic source was developed to examine the character of acoustic signals generated from the eruption governed by the geometry of the source and the physical properties of the magma. A magma pipe source mechanism within a partially submerged volcano was used to produce estimates of the seismo-acoustic wavefield within the Anatahan volcanic edifice. Sat, 01 Jan 2005 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5623 2005-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/7592 Title: 3-D GPR imaging and resisitivity structure by MT near King Sejong Station Authors: Shon, Howoong; Jin, Young Keun Abstract: In this study, a new high-frequency magnetotelluric (MT) technique has been used to analyze the deep subsurface architecture without the costly burden of a seismic-reflection survey. Profiles of high-resolution magnetotelluric data was acquired near King Sejong Station in the Antarctic interprets the data in terms of resistivity structure structures including faults. In addition to techniques used in polar regions, was applied to get the 3D subsurface imaging by 3D slicing across the crevasse developed in the glacier. Sat, 01 Jan 2005 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/7592 2005-01-01T00:00:00Z