1. Bucharest, 14-16 May 2007 1 Gerald Duma Central Institute for Meteorology and Geodynamics Vienna, Austria GEOMAGNETIC VARIATIONS AND EARTHQUAKE ACTIVITY 3 rd MagNetE Workshop on European Geomagnetic Repeat Station Survey

2. Bucharest, 14-16 May 2007 2 Observations (1996) – daily range AUSTRIA M  2.5, 1901-1990 Geomagnetic Observatory

3. Bucharest, 14-16 May 2007 3 Duma, Vilardo (INGV), 1998 Geomagnetic Observatory Observations (1997) – daily range Mt. VESUVIUS volcanic eqs, area 10 x 10 km, 1.8  M  3.1, 1972-1996, 1400 events

4. Bucharest, 14-16 May 2007 4 A seismic daily cycle  Greek philosophers  Pliny the Elder,  79 A.D. eruption of Mt.Vesuvius  Conrad, 1932  Shimshoni, 1972  Rarely investigated in recent decades

5. Bucharest, 14-16 May 2007 5 A seismic daily cycle 3 sub-periods 20th century AUSTRIA M  2.5 May 31 – June 18, 1997 Earthquake swarm in Austria, region IMST

6. Bucharest, 14-16 May 2007 6 A seismic daily cycle  Observed also in many other regions  Earthquakes M  5 and 6  A very powerful geodynamic process acting!

7. Bucharest, 14-16 May 2007 7 Geomagnetic Observatory Obs WIK, comp N AUSTRIA M  3.1 (Io  5°) Observations (1996) – long term

8. Bucharest, 14-16 May 2007 8 Mechanism, models?  Dependence on Local Time  Process related to sun  A mechanism which penetrates the whole Earth‘s lithosphere  Tides ? -> No!  High energy mechanism  Can a few nT influence tectonic performance?

9. Bucharest, 14-16 May 2007 9 The electromagnetic model  Geomagnetic variations reach deep into the Earth‘s interior, 100s and 1000s of km! (magnetotellurics)  Maxwell‘s equations : E - H relation (  )  Earth‘s conductive lithosphere: „telluric currents“ associated with all geomagnetic variations  Applies to all natural variations in a broad frequency range (from Hz – solar cycle)

10. Bucharest, 14-16 May 2007 10 The electromagnetic model  Telluric currents and forces F = e. [ v e. B ] F... mechanic force vector e... electron charge v e... velocity vector B... magnetic field vector ‚Lorentz force‘ F B veve e

11. Bucharest, 14-16 May 2007 11 The electromagnetic model  Magnetic observatories monitor vertical force Fv (t)

12. Bucharest, 14-16 May 2007 12 The electromagnetic model r P1 P2 I2 ≠ I1  Regional mechanic moment, torque Tr

13. Bucharest, 14-16 May 2007 13 A new meaning of variation  H  H: monitors change (  t) of vertical force  F v in P gradient  H: monitors change (  t) of regional mechanic moment  Tr ( azimuth Az) Torque axis P

14. Bucharest, 14-16 May 2007 14 Energy – diurnal variation  Sq: solar controlled, heating, ionization, tides (Chapman, Bartels, 1940)

15. Bucharest, 14-16 May 2007 15 Energy – diurnal variation T = MM x H A large scale current field, covering  1/3 of the northern Earth‘s hemisphere  The dayside Sq lithospheric current vortex (Matsushita, 1968)

16. Bucharest, 14-16 May 2007 16 Energy – diurnal variation  The mechanic moment of Sq for a single loop (Duma, Ruzhin, 2003) The example demonstrates: The deformation energy provided to the lithosphere by a single current loop, radius 1500 km and current 10 kA, is equivalent to the energy of an earthquake M 5,1.

17. Bucharest, 14-16 May 2007 17 Energy – diurnal variation  60% of total moment concentrates in a 30° segment H I

18. Bucharest, 14-16 May 2007 18 Modelling the electromagnetic effect  Data for  H(lat,long) to compute gradient Hourly values (diurnal variation):  Model simulating Sq telluric current vortex  Regional observatory data (average Sq-var.) Annual values (long term, secular variation):  Retrieved from IGRF, 1900-2010 (grid data)  Regional observatory data (annual means, SV)

19. Bucharest, 14-16 May 2007 19 Case studies – Regions AustriaTaiwan CaliforniaBaikal region

20. Bucharest, 14-16 May 2007 20 Case studies – Austria (M ≥ 3.2, Gradient  H – N10W) Gradient  H from IGRF10 (1900-2010) Diurnal range Long term 1900 - 2003 Gradient  H from Sq-Model

21. Bucharest, 14-16 May 2007 21 Case studies – Taiwan (M ≥ 5, Gradient  H – N55E) Gradient  H from IGRF10 (1900-2010) Diurnal range Long term Gradient  H from Sq-Model 1973 - 1998

22. Bucharest, 14-16 May 2007 22 Case studies – Baikal area (M ≥ 5, Gradient  H – N00E) Gradient  H from IGRF10 (1900-2010) Diurnal range Long term Gradient  H from Sq-Model 1900 - 1980 2001 - 2006

23. Bucharest, 14-16 May 2007 23 Case studies – California (M ≥ 6, Gradient  H – N30E) Gradient  H from IGRF10 (1900-2010) Diurnal range Long term Gradient  H from Sq-Model 1970 - 2005

24. Bucharest, 14-16 May 2007 24 Novel aspects  Geomagnetic variations modulate (trigger) seismic activity  Answer to daily rhythm of seismic activity  Activity ‚controlled‘ by external sources (sun, magnetic dynamo)  Monitoring: directly by geomagnetic observatories  Predictability: systematic diurnal, seasonal, secular variations (IGRF 2010)  Not yet investigated: influence of magnetic storms

25. Bucharest, 14-16 May 2007 25 Thank your for your attention !

26. Bucharest, 14-16 May 2007 26 A surprising but plausible model Magnetic observatories monitor horizontal force Fh C (t)

27. Bucharest, 14-16 May 2007 27 Mt. VESUVIUS – long term volcanic eqs, area 10 x 10 km, 1.8  M  3.1, 1972-1996, 1400 events Observations – sun spot cycles Duma, Vilardo (INGV), 1998 n: annual number of eqs M  1.8, 1972-1996 sf: annual number of solar flares (10 3 ) Duma, Vilardo (INGV), 1998

28. Bucharest, 14-16 May 2007 28 ITALY, 4 subregions / IONIAN ILANDS (G4) 1910 – 1980, M  5 Observations – daily range I1 I2 I3 I4 all Italy G4

29. Bucharest, 14-16 May 2007 29 The regional torque Tr – Energy > lithosphere block model <

30. Bucharest, 14-16 May 2007 30 Model of Sq telluric current vortex  Fits observed Sq-variations at observatories  Computes grad H(LT)

31. Bucharest, 14-16 May 2007 31  H – current density

32. Bucharest, 14-16 May 2007 32 Case studies – Austria (M ≥ 2.5, gradient  H – N10W) Seasonal range, 2001 - 2005  H data from observatories - monthly mean values

33. Bucharest, 14-16 May 2007 33 Case studies – Austria (M ≥ 2.5, gradient  H – N10W) Seasonal range, 2001 - 2005 Gradient  H from observatories - monthly mean values 2002 2001 2003 2004

34. Bucharest, 14-16 May 2007 34 Case studies – Austria (M ≥ 2.5, gradient  H – N10W) Seasonal range, 2001 - 2005 Gradient  H from observatories - monthly mean values 2005