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 Conductivity would be enhanced near epicenters during earthquakes Zeng et al. (1995)
Methodology PAzimuth (Dep)=arctan(Ar(f)/Br(f)) 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
嘉義、屏東與雲林 近距離小規模地震干擾 計算方法修改 2. 4 宜蘭 (5.6) 2. 26 霧台 (6.4) 3. 22 台東 (5.0) 4. 9 花蓮 太遠 4. 19 花蓮 (5.4) 4. 27 花蓮 (5.0) 6. 6 台東 (5.9) 6. 10 宜蘭 (6.5) 6. 15 花蓮 (5.4) 8. 14 花蓮 (5.2) 8. 18 台東 (5.2) 9. 5 台東 (5.2) 10.20宜蘭太遠 10.25 高雄 (5.5) 12.3 花蓮 (5.1) 12.22 蘭嶼 (5.5) 12.31 高雄 (5.4) 11.21 台東近海 (5.4) 1.4 宜蘭外海 (5.1) 嘉義、屏東與雲林 近距離小規模地震干擾 計算方法修改 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 23.68N 120.95E 0317 23.13N 120.78E 0317 22.89N 121.46E 0324
0327 地磁異常 CCU+HLG 10km YMM+HLG 10km 0319 0320 0321 0322 0323 0324 0325 0326 0327 0328 YMM+HLG 10km 0319 0320 0321 0322 0323 0324 0325 0326 0327 0328
結論與討論 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 2.21-2.27
327 地震影響範圍 307 地震干擾
應力逐漸達到飽和直到地震發生
水平向西垂直向下
達到飽和垂直向上
65days 327 54days