Possible precursors from GPS and geomagnetic anomaly

Presentation on theme: "Possible precursors from GPS and geomagnetic anomaly"— Presentation transcript:

1 Possible precursors from GPS and geomagnetic anomaly
陳界宏 中央研究院地球科學研究所

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3 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)

4 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

5 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

6 Locating earthquakes using seismo-magnetic anomalies
2013 Magnetic total intensity station 3-component magnetometer 2005 2013

7 CCU HLG 24.31N E

8 CCU HLG 23.68N E 0317 23.13N E 0317 22.89N E 0324

9 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

10 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

11 327 地震影響範圍 307 地震干擾

12 應力逐漸達到飽和直到地震發生

13 水平向西垂直向下

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15 達到飽和垂直向上

16 65days 327 54days