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Possible precursors from GPS and geomagnetic anomaly. 陳界宏 中央研究院地球科學研究所. 地震地磁異常. Seismo -magnetic emission waves Liu et al. (2006). Stress. Stress. Conductivity would be enhanced near epicenters during earthquakes Zeng et al. (1995). Methodology. Magnetic Transfer function
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Possible precursors from GPS and geomagnetic anomaly 陳界宏 中央研究院地球科學研究所
地震地磁異常 Seismo-magnetic emission waves Liu et al. (2006) Stress Stress Conductivity would be enhanced near epicenters during earthquakes Zeng et al. (1995)
Methodology • Magnetic Transfer function (Parkinson, 1962; Parkinson and Jones, 1979, Zeng and Lin, 1995) ΔZ = A∙ΔH + B∙ΔD Coefficients A and B are transfer functions influenced by the underlying electrical conductivity structure ΔZ, ΔH and ΔD are derived from the magnetic data by using the Fourier transform and are frequency dependent. • Skin effects (Cheng, 1989; Simpson and Bahr, 2005) Dep=503(ρ/ f)1/2 Dep is depth (meter) ρ is electrical resistivity (ohm-meter) f is frequency (Hz) • Relationships between ρ and depth sections near the CCU station are conducted by using the previous magnetotelluric studies (Bertrand, 2009; Chiang, 2010) PAzimuth(Dep)=arctan(Ar(f)/Br(f)) PMagnitude(Dep)=(Ar(f)2+Br(f)2)1/2
6. 6 台東 (5.9) 4.9 花蓮 太遠 2. 4 宜蘭 (5.6) 9. 5 台東(5.2) 3. 22 台東 (5.0) 4. 27 花蓮 (5.0) 2. 26 霧台 (6.4) 4. 19 花蓮 (5.4) 12.22 蘭嶼(5.5) 12.31 高雄 (5.4) 12.3 花蓮 (5.1) 6. 10 宜蘭(6.5) 6. 15 花蓮(5.4) 8. 14 花蓮(5.2) 8. 18 台東(5.2) 10.25 高雄 (5.5) 1.4 宜蘭外海 (5.1) 10.20宜蘭太遠 11.21 台東近海(5.4) 計算方法修改 嘉義、屏東與雲林 近距離小規模地震干擾 M4.5 澎湖縣政府北方 43.7 公里
Locating earthquakes using seismo-magnetic anomalies 2013 Magnetic total intensity station 3-component magnetometer 2005 2013
20130306 CCU HLG 24.31N 121.49E
20130316 CCU HLG 23.68N120.95E 0317 23.13N120.78E 0317 22.89N121.46E 0324
0327 地磁異常 CCU+HLG 10km 0319 0320 0321 0322 0323 0324 0325 0326 0327 0328 0319 0320 0321 0322 0323 YMM+HLG 10km 0324 0325 0326 0327 0328
結論與討論 2.21-2.27 • 地殼水平向西運動 1.20 – 2.1 • 地殼垂直向下運動 1.20 – 2.1 • 地殼垂直向上運動 2.21 – 2.27 • 地磁異常 3.21 – 3.27 • 地磁多站定位方法,仍需改良 1.20-2.1
327 地震影響範圍 307 地震干擾
65days 327 54days