Determination of Epicenters before Earthquakes Utilizing Far Seismic and GNSS Data: Insights from Ground Vibrations

• Published in: Remote sensing (Basel, Switzerland) Vol. 12; no. 19; p. 3252
• Main Authors: Chen, Chieh-Hung, Lin, Li-Ching, Yeh, Ta-Kang, Wen, Strong, Yu, Huaizhong, Yu, Chen, Gao, Yongxin, Han, Peng, Sun, Yang-Yi, Liu, Jann-Yenq, Lin, Cheng-Horng, Tang, Chi-Chia, Lin, Che-Min, Hsieh, Hung-Hao, Lu, Pin-Ji
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2020
• Subjects: Anomalies; behavior; Broadband; common-mode ground vibrations; Data processing; Earthquakes; geophysics; Global navigation satellite system; Global positioning systems; GPS; Ground motion; length; Navigation satellites; pre-earthquake anomalous phenomena; pre-earthquake ground motion; Principal components analysis; Propagation; remote sensing; Satellite observation; Seismic activity; Seismographs; Taiwan; Velocity; Vibrations; Taiwan
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs12193252

Broadband seismometers, ground-based Global Navigation Satellite Systems (GNSS), and magnetometers that were located within an epicentral distance of approximately 150 km consistently observed the novel anomalous behaviors of the common-mode ground vibrations approximately 5–10 days before the M6.6 Meinong earthquake in Taiwan. The common-mode ground vibrations with amplitudes near 0.1 m at frequencies ranging from 8 × 10−5 to 2 × 10−4 Hz were generated near the region close to the epicenter of the impending earthquake. The common-mode vibrations were consistently observed in seismic and GNSS data associated with five other earthquakes in four distinct areas. The results reveal that the common-mode vibrations could be a typical behavior before earthquakes. The causal mechanism of common-mode vibrations can be attributed to crustal resonance excitations before fault dislocations occur. Potential relationships with other pre-earthquake anomalies suggest that the common-mode vibrations could be ground motion before earthquakes, which was investigated for a significant length of time.