[S-CG45] Science of slow-to-fast earthquakes

[SCG45-P28] Status of Yemi Microgravity Observatory and the ENIGMA Collaboration

*JeongCho Kim¹, Whansun Kim¹, Edwin Jaeju Son¹, Seung Yeon Oh¹, Jeong Woo Kim², Jungkeun John Oh¹ (1.Gravity Research and Application Team, National Institute for Mathematical Sciences, Daejeon, Republic of Korea., 2.Department of Geomatics Engineering, University of Calgary, Calgary, Canada.)

Keywords:Superconducting Gravimeter, Underground Laboratory, Micro-gravity, Co-seismic change

We report the installation, operation, and current gravity data analysis of the Yemi Micro-Gravity Observatory (YeMiGO). In October 2022, we installed GWR Instruments Inc.'s iGrav (serial #001) superconducting gravimeter (SG) at YemiLab, an underground research facility in South Korea located 1,008 m below the surface. Noise analysis conducted in September 2023 confirmed the stability of the lab, showing low noise levels in the seismic band. A calibration factor of -92.17 μGal/V was estimated from tidal analysis between November 2022 and May 2023, and an updated value of -94.15 μGal/V was obtained in November 2023 through parallel measurements with FG5-231. After accounting for environmental factors, spectral analysis revealed unidentified frequencies requiring further investigation, and we analyze the variations in the noise power spectrum observed to date. We introduce the ENIGMA collaboration, which integrates superconducting gravimeter data from Korea, Japan, China, and Taiwan, and report the progress of its applied research. Additionally, we discuss applications of this network, including PEGS detection, dark matter searches, and underground environmental noise studies.