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

Abstract We investigate the upper‐crustal seismic velocity structure in the Seoul metropolitan area, where about 20 million people live. The Chugaryeong fault zone (CFZ) is placed in this area, but the seismic hazard potential remains unclear. We conducted ambient noise tomography to illuminate the...

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Autores principales:	Dongwoo Kil, Tae‐Kyung Hong, Dongchan Chung, Byeongwoo Kim, Junhyung Lee, Seongjun Park
Formato:	article
Lenguaje:	EN
Publicado:	American Geophysical Union (AGU) 2021
Materias:	Seoul urban region active fault ambient noise tomography seismicity upper crust Astronomy QB1-991 Geology QE1-996.5
Acceso en línea:	https://doaj.org/article/0ab619501e3f4ea891773f3d8d4a9fd4
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id	oai:doaj.org-article:0ab619501e3f4ea891773f3d8d4a9fd4
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spelling	oai:doaj.org-article:0ab619501e3f4ea891773f3d8d4a9fd42021-11-23T21:03:09ZAmbient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications2333-508410.1029/2021EA001983https://doaj.org/article/0ab619501e3f4ea891773f3d8d4a9fd42021-11-01T00:00:00Zhttps://doi.org/10.1029/2021EA001983https://doaj.org/toc/2333-5084Abstract We investigate the upper‐crustal seismic velocity structure in the Seoul metropolitan area, where about 20 million people live. The Chugaryeong fault zone (CFZ) is placed in this area, but the seismic hazard potential remains unclear. We conducted ambient noise tomography to illuminate the high‐resolution upper‐crustal structure in the Seoul metropolitan area. We analyzed continuous vertical seismic records for ∼5 months from a dense seismic array with 77 broadband stations. Group velocity dispersion curves and tomographic maps were extracted between 0.5 and 10 s periods. We inverted 3‐D group velocity tomography models up to a depth of ∼10 km from the group velocity maps. The shear‐wave velocity model is consistent with the geological features. High‐velocity anomalies at shallow depths are correlated with the surface topography and geology. The CFZ is located at a low velocity below the 5 km depth and presented as the simplified model. The large VS contrast regions are located beneath NS‐trending faults. The cross‐sections coincide with the near‐vertical strike‐slip faults in this area. In the southern region of the Seoul metropolitan area, low‐velocity anomalies correlate with high heat flow regions. Our results effectively suggest high resolution upper‐crustal structures and subsurface hidden faults in the urban area.Dongwoo KilTae‐Kyung HongDongchan ChungByeongwoo KimJunhyung LeeSeongjun ParkAmerican Geophysical Union (AGU)articleSeoulurban regionactive faultambient noise tomographyseismicityupper crustAstronomyQB1-991GeologyQE1-996.5ENEarth and Space Science, Vol 8, Iss 11, Pp n/a-n/a (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Seoul urban region active fault ambient noise tomography seismicity upper crust Astronomy QB1-991 Geology QE1-996.5
spellingShingle	Seoul urban region active fault ambient noise tomography seismicity upper crust Astronomy QB1-991 Geology QE1-996.5 Dongwoo Kil Tae‐Kyung Hong Dongchan Chung Byeongwoo Kim Junhyung Lee Seongjun Park Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
description	Abstract We investigate the upper‐crustal seismic velocity structure in the Seoul metropolitan area, where about 20 million people live. The Chugaryeong fault zone (CFZ) is placed in this area, but the seismic hazard potential remains unclear. We conducted ambient noise tomography to illuminate the high‐resolution upper‐crustal structure in the Seoul metropolitan area. We analyzed continuous vertical seismic records for ∼5 months from a dense seismic array with 77 broadband stations. Group velocity dispersion curves and tomographic maps were extracted between 0.5 and 10 s periods. We inverted 3‐D group velocity tomography models up to a depth of ∼10 km from the group velocity maps. The shear‐wave velocity model is consistent with the geological features. High‐velocity anomalies at shallow depths are correlated with the surface topography and geology. The CFZ is located at a low velocity below the 5 km depth and presented as the simplified model. The large VS contrast regions are located beneath NS‐trending faults. The cross‐sections coincide with the near‐vertical strike‐slip faults in this area. In the southern region of the Seoul metropolitan area, low‐velocity anomalies correlate with high heat flow regions. Our results effectively suggest high resolution upper‐crustal structures and subsurface hidden faults in the urban area.
format	article
author	Dongwoo Kil Tae‐Kyung Hong Dongchan Chung Byeongwoo Kim Junhyung Lee Seongjun Park
author_facet	Dongwoo Kil Tae‐Kyung Hong Dongchan Chung Byeongwoo Kim Junhyung Lee Seongjun Park
author_sort	Dongwoo Kil
title	Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
title_short	Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
title_full	Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
title_fullStr	Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
title_full_unstemmed	Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications
title_sort	ambient noise tomography of upper crustal structures and quaternary faults in the seoul metropolitan area and its geological implications
publisher	American Geophysical Union (AGU)
publishDate	2021
url	https://doaj.org/article/0ab619501e3f4ea891773f3d8d4a9fd4
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Ambient Noise Tomography of Upper Crustal Structures and Quaternary Faults in the Seoul Metropolitan Area and Its Geological Implications

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