https://repository.kopri.re.kr/handle/201206/5169 2026-04-07T05:39:40Z 2026-04-07T05:39:40Z Robert P. Dziak Haru Matsumoto Joseph H. Haxel DelWayne R. Bohnenstiehl Lee, Won Sang Park, Minkyu https://repository.kopri.re.kr/handle/201206/6345 2022-03-24T07:12:25Z 2010-01-01T00:00:00Z

Title: Tectonomagmatic activity and ice dynamics in the Bransfield Strait back-arc basin, Antarctica Authors: Robert P. Dziak; Haru Matsumoto; Joseph H. Haxel; DelWayne R. Bohnenstiehl; Lee, Won Sang; Park, Minkyu Abstract: An array of moored hydrophones was used to monitor the spatiotemporal distribution of small- to moderate-sized earthquakes and ice-generated sounds within the Bransfield Strait, Antarctica. During a 2 year period, a total of 3900 earthquakes, 5925 icequakes and numerous ice tremor events were located throughout the region. The seismic activity included eight space-time earthquake clusters, positioned along the central neovolcanic rift zone of the young Bransfield back-arc basin. These sequences of small magnitude earthquakes, or swarms, suggest ongoing magmatic activity that becomes localized along isolated volcanic features and fissure-like ridges in the southwest portion of the basin. A total of 122 earthquakes were located along the South Shetland trench, indicating continued deformation and possibly ongoing subduction along this margin. The large number of icequakes observed show a temporal pattern related to seasonal freeze-thaw cycles and a spatial distribution consistent with channeling of sea ice along submarine canyons from glacier fronts. Several harmonic tremor episodes were sourced from a large (~30 km2) iceberg that entered northeast portion of the basin. The spectral character of these signals suggests they were produced by either resonance of a small chamber of fluid within the iceberg, or more likely, due to periodicity of discrete stick-slip events caused by contact of the moving iceberg with the seafloor. These pressure waves appear to have been excited by abrasion of the iceberg along the seafloor as it passed Clarence and Elephant Islands.

2010-01-01T00:00:00Z Yu, Chanho Paul Xu Kim, Kwang-Hee Park, Yongcheol Kang, Suyoung Suk, Bongchool Suh, Mancheol https://repository.kopri.re.kr/handle/201206/6081 2022-03-24T07:12:30Z 2010-01-01T00:00:00Z

Title: Crust and upper mantle structure beneath the Yellow Sea region using receiver function analysis Authors: Yu, Chanho; Paul; Xu; Kim, Kwang-Hee; Park, Yongcheol; Kang, Suyoung; Suk, Bongchool; Suh, Mancheol Abstract: Teleseismic events are used to obtain shear-wave velocity models beneath the stations of the Yellow Sea Broadband Seismic Network (YSBSN). Some stations are located on top of either a thick sedimentary basin or highly porous volcanic rocks and receiver functions at these stations exhibit prominent high-amplitude and long-period reverberations which obscure the subtle phases associated with deeper structures. Due to the shallow subsurface effects in receiver functions, shear-wave velocity models beneath only 8 broadband seismic stations are successfully inverted. Depth to the crust？antle transition (the Moho) varies from 30 to 38 km beneath YSBSN stations. The thickest crust is observed beneath the station JNN in China, which is attributed to the ancient collision boundary between the North China block and the South China block. Although general increase of the crustal thickness from north to south in Korea is observed with high confidence, it is not possible to delineate the location of potential collision boundary in the southern Korea peninsula, which would require wider coverage by broadband seismic instruments to resolve.

2010-01-01T00:00:00Z Park, Yongcheol Lee, Ju-Han Park, Minkyu Kim, Kwang-Hee Park, Sun-Cheon https://repository.kopri.re.kr/handle/201206/6169 2022-03-24T07:11:29Z 2010-01-01T00:00:00Z

Title: Magnitude scaling relationships from the first 3 s of P-wave arrivals in South Korea Authors: Park, Yongcheol; Lee, Ju-Han; Park, Minkyu; Kim, Kwang-Hee; Park, Sun-Cheon Abstract: Two empirical magnitude scaling relationships, predominant period (τ max p ) and peak ground displacement (Pd) magnitudes, were investigated for the first 3 s after P-wave arrivals using 1,412 vertical waveforms recorded by the Korea National Seismic Network (KNSN) between 2001 and 2007. To evaluate the accuracy of the derived magnitude relationships, we simulated off-line ElarmS tests using 65 events occurring inside the KNSN. While the average magnitude error was ∼0.70 magnitude units when using only the closest station to the epicentre, the error dropped to ∼0.62 and ∼0.42 magnitude units when using the closest two and closest four stations, respectively. For events ML ≥ 3.0, the average magnitude error was ∼0.33 and showed stable values when the closest four stations were available. Our magnitude scaling relationships may be useful for initial work in developing an earthquake early warning system in South Korea.

2010-01-01T00:00:00Z Yun, Sukyoung Park, Minkyu Lee, Won Sang Sidao Ni https://repository.kopri.re.kr/handle/201206/6407 2022-03-24T07:11:29Z 2009-01-01T00:00:00Z

Title: Southeast Indian Ocean-Ridge earthquake sequences from cross-correlation analysis of hydroacoustic data Authors: Yun, Sukyoung; Park, Minkyu; Lee, Won Sang; Sidao Ni Abstract: Parameters of earthquake sequences, for instance location and timing of foreshocks and aftershocks,are critical for understanding dynamics ofmid-ocean ridge and transformfaults.Whole sequences including small earthquakes in the ocean cannot be well recorded by land-based seismometers due to large epicentral distances. Recent hydroacoustic studies have demonstrated that T waves are very effective in detecting small submarine earthquakes because of little energy loss during propagation in Sound Fixing and Ranging channel. For example, an MW6.2 (2006 March 6, 40.11？S/78.49？E) transform-fault earthquake occurred at the Southeastern Indian Ocean Ridge, but National Earthquake Information Center only reported three aftershocks in the first following week. We applied cross-correlation method to hydroacoustic data from the International Monitoring System arrays in the Indian Ocean to examine thewhole earthquake sequence. We detected 14 aftershocks and none foreshock for the earthquake and locations of these aftershocks show an irregular pattern. From the observation, we suggest that the feature could be caused by complicated transcurrent plate-boundary dynamics between two overlapped spreading ridges that is possibly explained by the bookshelf faulting model.

2009-01-01T00:00:00Z