Hongseong Geophone Array 2023

map of Hongseong Geophone Array

(figured by Minkyung Kim)

Hongseong region has been considered as an extension of collision between North China Craton and South China Block, and it has been reported that serpentinite and eclogite exist in this region (e.g. Park and Jung, 2017). Moreover, there are faults related to shear zone (Hongseong faults and Yaesan faults). We deployed 113 linear geophone array as well as two additional geophones for a month (2023.10.25-2023.11.27) to investigate detailed crustal structures regarding fault directions and anisotropy.

During the operation period, two events (2023.10.25, ML 3.4; 2023.11.25, ML 2.6) were reported (based on KMA).

localevent_01.xlsx

Participants of the Campaign

participants of the campaign

Seoul National University, Republic of Korea

Pukyong National University, Republic of Korea

Korea Institue of Geoscience and Mineral Resources (KIGAM), republic of Korea



Teleseismic events during the deployment (2023.10.25-2023.11.27, M>6.0, 30deg<DIST<90deg, N=12)

teleseismic_events

(figured by Minkyung Kim)


Research Topics

- Receiver function analysis (crust-uppermost mantle structure) : Minkyung Kim (SNU, shinyjade@snu.ac.kr)

- SWS using local earthquakes (crustal anisotropy) : Seung-Heon Choi (SNU, spica6375@snu.ac.kr)

- Ambient noise double beamforming tomography : Min Hyug Koh (SNU, minhyug.koh@gmail.com)

- Auto-correlation : Hyejeong Cho (SNU, hyejeongcho479@gmail.com)

- Ray-traveltime forward modeling : Minog Kim (PKNU, minog19@gmail.com)

- HVSR (shallow crust) : Byeong Seok Ahn (PKNU, 11196abs@gmail.com)

- Earthquake detection : Dabeen Heo (PKNU, hdb4812@gmail.com)


Map of the stations

HS_station.xlsx

Previous Geological Researches

Arai, S., Tamura, A., Ishimaru, S., Kadoshima, K., Lee, Y. I., & Hisada, K. I. (2008). Petrology of the Yugu peridotites in the Gyeonggi Massif, South Korea: implications for its origin and hydration process. Island Arc, 17(4), 485-501.

Cho, H. M., Baag, C. E., Lee, J. M., Moon, W. M., Jung, H., Kim, K. Y., & Asudeh, I. (2006). Crustal velocity structure across the southern Korean Peninsula from seismic refraction survey. Geophysical Research Letters, 33(6).

Jung, H., Jang, Y. S., Lee, J. M., Moon, W. M., Baag, C. E., Kim, K. Y., & Jo, B. G. (2007). Shear wave velocity and attenuation structure for the shallow crust of the southern Korean peninsula from short period Rayleigh waves. Tectonophysics, 429(3-4), 253-265.

Kim, K. Y., Lee, J. M., Baag, C. E., Moon, W. M., Jung, H., & Lee, S. Y. (2007). Seismic reflection image of the crust structure along the KCRT-2002 profile in the southern Korean peninsula. Geosciences Journal, 11, 219-228.

Park, M., & Jung, H. (2017). Microstructural evolution of the Yugu peridotites in the Gyeonggi Massif, Korea: Implications for olivine fabric transition in mantle shear zones. Tectonophysics, 709, 55-68.

이정모, 문우일, 박창업, 정희옥, 김기영, 조봉곤, ... & 김성균. (2003). 서산-영동-경주 지각규모 굴절파실험 초기분석결과. 대한지질학회 학술대회, 31-31.

장용석, 정희옥, 조봉곤, 이정모, 문우일, 박창업, & 김기영. (2005). 지각규모 굴절파 실험 자료의 표면파 분석을 통한 한반도 천부지각속도구조 연구. 대한지질학회 학술대회, 53-53.


Instrumental Response

paz={'poles': [(-22.211059+22.217768j), (-22.211059-22.217768j)], 'zeros': [0j, 0j], 'sensitivity': 76.7, 'gain': 2**23/2.5}


Orientation Correction

Orientation.xlsx

We used 12 teleseismic events (mentioned above) during the operation period to perform orientation corrections at each station. For more information, refer to the pdf file below.

short_note_for_orientation_correction.pdf

Spectral Estimation

ppsd.zip

Power spectral density for each station was estimated by using the obspy code ( https://docs.obspy.org/packages/autogen/obspy.signal.spectral_estimation.PPSD.html).


History

Preliminary Investigation (2023/09/13-2023/09/16)

Deploying Geophone Array (2023/10/24-2023/10/27)

Retrieving Geophone Array (2023/11/27-2023/11/28)


Site Administrator

Seung-Heon Choi

Combined master's/doctoral Course Student at Seoul National University

spica6375@gmail.com