Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications

Kil, Dongwoo; Hong, Tae‐Kyung; Chung, Dong-Yong; Kim, Byeong-Woo; Lee, Junhyung; Park, Seongjun

doi:10.1029/2021ea001983

Cited by 12 publications

(19 citation statements)

References 121 publications

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“…Chwae et al (1996) (Cho et al, 2007). (Kil et al, 2021) along the seismic profile. The western region from the DF is characterized by high shear wave velocity to a depth of 3 km, while the eastern region shows relatively low velocity.…”

Section: 지질구조 및 단층mentioning

confidence: 99%

“…서 언 한반도 중부의 수도권 지역에는 2016년에 경주지진을 일으킨 양산단층보다 규모가 큰 추가령 단층대(Fig. 1A 의 CFS 단층선)가 북북동-남남서 방향으로 관통하고 있 다 (Choi et al, 2012;Chung et al, 2014;Choi et al, 2021a;Kil et al, 2021;. 만약 추가령 단층대가 활성화되어 경주지진과 비슷한 규모의 지진이 발생할 경우, 2,500만 명 이상의 인구가 집중된 수도권 지역에 미치는 물리적, 심리적 충격은 경주지진 비해 몇 배 더 클 것으로 예측된다.…”

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“…1C 의 빨간색 세모)의 지진이 관측되었고 최대 규모와 평균 규모는 M2.9와 M1.4였다. 반면, 경주지진 이후 2018년 부터 2021년까지 4년간 303 회로 지진의 발생 빈도가 증 가하였고 (Kil et al, 2021;Lee et al, 2022), 지진규모가 1.0 미만의 군발성 지진을 특징으로 한다(연세대학교 자 료 제공). 더욱이 이 지역에서 최근에 발생한 미소지진의 대부분이 동두천 단층과 인접한 지역에서 집중적으로 발 생하였다는 것이 우려되는 점이다(Fig.…”

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Analysis of the Causes of Clustered Scismicity Registered in Yeoncheon, the Middle Part of the Korean Peninsula through Gravity Field Interpretation and Modeling

Choi¹,

Kim²,

Choi³

et al. 2022

Econ. Environ. Geol.

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Gravity data were analyzed to identify the cause of clustered seismicity that occurred intensively in Yeoncheon, located in the central part of the Korean Peninsula. Our analysis suggests that the En echelon faults developed in the northwest-southeast direction. In addition, in the eastern part of the Dongducheon Fault, it was interpreted that high-density lower bedrock intermittently lifts close to the surface due to vertical tectonic movement accompanied by a flower structure. The fracture zone of the Dongducheon Fault is estimated that the width is about 200 m, the depth is at least 5 km, and the density is about 15% lower than the adjacent rocks. It is analyzed that the shallow earthquakes that occurred within 5 km depth was concentrated along the low-density En echelon fault fracture zone developed between the high-density rocks intruding close to the surface. Therefore, the earthquakes can be interpreted as the result that the north-south stress caused by the dextral tectonic movement of the Dongducheon Fault activated the En echelon fault in the northwest-southeast direction.

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Section: 지질구조 및 단층mentioning

confidence: 99%

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Analysis of the Causes of Clustered Scismicity Registered in Yeoncheon, the Middle Part of the Korean Peninsula through Gravity Field Interpretation and Modeling

Choi¹,

Kim²,

Choi³

et al. 2022

Econ. Environ. Geol.

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“…Historical earthquake damage records present the occurrence of major earthquakes with magnitudes of ∼ M L 6.8 in the Seoul metropolitan area (Houng & Hong, 2013; Park et al., 2020). Earthquakes in the Seoul metropolitan area present spatial clustering around major fault systems (Hong et al., 2021; Kil et al., 2021). Quaternary faults in the region may be responsible for the historical earthquakes (S.‐J.…”

Section: Introductionmentioning

confidence: 99%

Role of Backbone Fault System on Earthquake Spawning and Geohazards in the Seoul Metropolitan Area

Park

Hong

Kim

et al. 2023

Earth and Space Science

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Major earthquakes in continental regions may cause significant damage. Preexisting fault system across megacity receives high attention for possible seismic damages. Earthquake occurrence mechanism is important to assess the geohazard potentials. Continental‐scale Quaternary fault system is developed across the Seoul metropolitan area where the population is the largest in the Korean Peninsula. Historical seismic‐damage records suggest potential seismic hazards in the Seoul metropolitan area. We investigate the fault motions and spatial distribution of earthquakes in the Seoul metropolitan area using a matched‐filter technique that is based on stacked waveform crosscorrelation functions among densely‐deployed seismic stations. The analysis detects 1103 earthquakes that include 360 events with magnitudes (ML) of −0.6 to 2.0 around the Chugaryeong fault and 34 events with magnitudes of −0.5 to 2.7 around Wangsukcheon, Pocheon, and Yeseonggang faults. The seismicity suggests a set of near‐vertical subparallel (or orthogonal) faults that develop from the major faults. A major fault system behaves as a backbone structure that makes branch faults develop, producing seismicity including major earthquakes. The backbone structure may control the fault development that conforms to the ambient stress field. The backbone faults may play a role to increase geohazard potentials.

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“…UAN has been applied in many applications, such as in obtaining microzonation maps (Ashayeri et al, 2020), soil mapping (Wathelet et al, 2020) or monitoring traffic noise (Zambon et al, 2018), economic growth (Hong et al, 2020), or cultural events (Kil et al, 2021), global climate imprints (Stutzmann et al, 2009), engineering geology (Iannucci et al, 2018) geohazards such as landslides (Hussain et al, 2019), volcanos (De Plaen et al, 2019 and hydrology (Tribaldos and Ajo-Franklin, 2021). All applications of ambient noise require its stability over time.…”

Section: Introductionmentioning

confidence: 99%

Variabilities in Urban Ambient Noise Before, During, and After Covid-19 Lockdown in the Peruvian Capital

et al. 2022

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ABSTRACT. Recent studies have shown that urban ambient noise (UAN) decreased at many sites due to a slowdown in human activities brought by the SARS-CoV-2 (COVID-19) pandemic lockdowns. Such understanding is inferred from the historical record of the noise levels, which may also help us disambiguate noise sources as required for ambient noise tomography, microseismic and other seismic based studies. As UAN is site-specific, and its analysis enables passive situational awareness, therefore, in the present study, we analyzed the temporal variations in UAN before, during and after the social isolation in the metropolitan region of Lima, the capital of Peru, for the very first time. We used continuous waveforms recorded from February 1st to August 31st, 2020, at the Ñaña (NNA) broadband seismic station for the analysis. Results show the temporal changes occur in different frequency ranges; for example, at frequencies >1 Hz, significant changes in the mean daytime amplitudes are observed, which are absent in the lower frequency range (0.1–1, 1–3, 3–5 Hz). A maximum noise reduction of 37% is observed and should be considered for any future application of UAN. The results were verified by comparing with Community Mobility Reports (CMR) provided by Google using statistical change-point analysis.

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Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications

Cited by 12 publications

References 121 publications

Analysis of the Causes of Clustered Scismicity Registered in Yeoncheon, the Middle Part of the Korean Peninsula through Gravity Field Interpretation and Modeling

Analysis of the Causes of Clustered Scismicity Registered in Yeoncheon, the Middle Part of the Korean Peninsula through Gravity Field Interpretation and Modeling

Role of Backbone Fault System on Earthquake Spawning and Geohazards in the Seoul Metropolitan Area

Variabilities in Urban Ambient Noise Before, During, and After Covid-19 Lockdown in the Peruvian Capital

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