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Main Authors: Yang, Yuxin, Liu, Kun, Zhang, Xuefeng, Hu, Yi-Ming
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.10107
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author Yang, Yuxin
Liu, Kun
Zhang, Xuefeng
Hu, Yi-Ming
author_facet Yang, Yuxin
Liu, Kun
Zhang, Xuefeng
Hu, Yi-Ming
contents The measurement of Earth's free oscillations plays an important role in studying the Earth's large-scale structure. Space technology development presents a potential method to observe these normal modes by measuring inter-satellite distances. However, the disturbance from the Earth's low-degree gravity field makes it challenging for low Earth orbit gravity measurement satellites such as Gravity Recovery and Climate Experiment (GRACE) and TianQin-2 to extract signals from Earth's free oscillations directly. Here, we propose that by taking advantage of the high Earth orbit, the TianQin satellites can effectively avoid this disturbance, enabling direct measurement of Earth's free oscillations. We derive an analytical waveform to describe the response of Earth's free oscillations in TianQin. Based on this waveform, we use Bayesian analysis to extract the normal modes from numerical simulation data and perform parameter estimation. Our findings reveal that for a magnitude 7.9, Wenchuan-like earthquake, the resulting free oscillations will generate a signal that signal-to-noise ratio (SNR) is 73 in TianQin, and approximately 9 different modes can be distinguished. This result shows TianQin can open a new window to examine the Earth's free oscillations and study the Earth's interior and earthquakes independently from ground-based gravity measurement.
format Preprint
id arxiv_https___arxiv_org_abs_2510_10107
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Detection of Earth's free oscillations utilizing TianQin
Yang, Yuxin
Liu, Kun
Zhang, Xuefeng
Hu, Yi-Ming
Geophysics
General Relativity and Quantum Cosmology
The measurement of Earth's free oscillations plays an important role in studying the Earth's large-scale structure. Space technology development presents a potential method to observe these normal modes by measuring inter-satellite distances. However, the disturbance from the Earth's low-degree gravity field makes it challenging for low Earth orbit gravity measurement satellites such as Gravity Recovery and Climate Experiment (GRACE) and TianQin-2 to extract signals from Earth's free oscillations directly. Here, we propose that by taking advantage of the high Earth orbit, the TianQin satellites can effectively avoid this disturbance, enabling direct measurement of Earth's free oscillations. We derive an analytical waveform to describe the response of Earth's free oscillations in TianQin. Based on this waveform, we use Bayesian analysis to extract the normal modes from numerical simulation data and perform parameter estimation. Our findings reveal that for a magnitude 7.9, Wenchuan-like earthquake, the resulting free oscillations will generate a signal that signal-to-noise ratio (SNR) is 73 in TianQin, and approximately 9 different modes can be distinguished. This result shows TianQin can open a new window to examine the Earth's free oscillations and study the Earth's interior and earthquakes independently from ground-based gravity measurement.
title Detection of Earth's free oscillations utilizing TianQin
topic Geophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2510.10107