Europlanet Graz, 1-2 June Gerald Duma Central Institute for Meteorology and Geodynamics Vienna, Austria AN ELECTROMAGNETIC PROCESS REGULATES EARTHQUAKE ACTIVITY Workshop Earthquakes: Ground-based and Space Observations

Europlanet Graz, 1-2 June Studies performed  10-year research pogramme  Several cooperations in Europe, Asia, America  Effect verified for many earthquake zones worldwide  Plausible interpretation and model

Europlanet Graz, 1-2 June Observations (1996) – daily range AUSTRIA M  2.5, Geomagnetic Observatory

Europlanet Graz, 1-2 June Duma, Vilardo (INGV), 1998 Geomagnetic Observatory Observations (1997) – daily range Mt. VESUVIUS volcanic eqs, area 10 x 10 km, 1.8  M  3.1, , 1400 events

Europlanet Graz, 1-2 June A seismic daily cycle  Aristoteles  Pliny the Elder,  79 A.D. eruption of Mt.Vesuvius  Tams, 1926  Conrad, 1932  Shimshoni, 1972  Lipovics, 2000, 2005  Schekotov & Molchanov, 2005  Poorly investigated in recent decades, no interpretation given yet

Europlanet Graz, 1-2 June A seismic daily cycle 3 sub-periods 20th century AUSTRIA M  2.5 May 31 – June 18, 1997 Earthquake swarm in Austria, region IMST

Europlanet Graz, 1-2 June A seismic daily cycle  Observed in many main seismic regions  Earthquakes M  5 and M  6  A very powerful geodynamic process acting!

Europlanet Graz, 1-2 June Geomagnetic Observatory Obs WIK, comp N ‚ secular variation‘ AUSTRIA M  3.1 (Io  5°) Observations (1996) – long term

Europlanet Graz, 1-2 June 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?

Europlanet Graz, 1-2 June The electromagnetic model  Geomagnetic variations in a conductive lithosphere  Maxwell‘s equations (E-H)  ‚Telluric currents‘ associated with all natural geomagnetic variations (frequency range from min – solar cycle)

Europlanet Graz, 1-2 June 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

Europlanet Graz, 1-2 June The electromagnetic model  Magnetic observatories monitor:  H(t) ~  I H (t) ~  F V (t) vertical force

Europlanet Graz, 1-2 June The electromagnetic model r P1 P2 I2 ≠ I1  Regional mechanic moment, torque Tr

Europlanet Graz, 1-2 June The electromagnetic model  The gradient of  H(t) reflects the change of regional torque  Tr(t) (azimuth Az) Torque axis P

Europlanet Graz, 1-2 June Energy – diurnal variation T = MM x H A large scale current field, covering  1/3 of the northern Earth‘s hemisphere  The dayside Sq induced lithospheric current vortex (Chapman, Bartels, 1940; Matsushita, 1968)

Europlanet Graz, 1-2 June 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.

Europlanet Graz, 1-2 June Energy – diurnal variation  60% of total moment concentrates in a 30° segment H I

Europlanet Graz, 1-2 June Modelling the electromagnetic effect  Data for  H(lat,long) to compute gradient Daily variation: hourly mean values  Model of Sq telluric current vortex  Regional observatory data (lat i, long i ) Long term: annual mean values  Retrieved from IGRF, (grid data)  Regional observatory data (lat i, long i )

Europlanet Graz, 1-2 June Case studies – Regions AustriaTaiwan CaliforniaBaikal region

Europlanet Graz, 1-2 June Case studies – Austria (M ≥ 3.2, Gradient  H – N10W) Gradient  H from IGRF10 ( ) Diurnal range Long term Gradient  H from Sq-Model

Europlanet Graz, 1-2 June Case studies – Taiwan (M ≥ 5, Gradient  H – N55E) Gradient  H from IGRF10 ( ) Diurnal range Long term Gradient  H from Sq-Model

Europlanet Graz, 1-2 June Case studies – Baikal area (M ≥ 5, Gradient  H – N00E) Gradient  H from IGRF10 ( ) Diurnal range Long term Gradient  H from Sq-Model

Europlanet Graz, 1-2 June Case studies – California (M ≥ 6, Gradient  H – N30E) Gradient  H from IGRF10 ( ) Diurnal range Long term Gradient  H from Sq-Model

Europlanet Graz, 1-2 June Case study – earthquakes – , M  5 S-ITALY IONIAN IS AEGEAN

Europlanet Graz, 1-2 June Case study – earthquakes IONIAN ISLANDS Seismic activity – Local Time M  – 1989 (25 yrs, PDE) 1990 – 2003 (14 yrs, PDE) – M  5 n = 11 (PDE) Gradient  H (N85E)

Europlanet Graz, 1-2 June Case study – earthquakes – 1980 (72 yrs, INGV) – M  5 n = 4 (PDE) – M  4.5 n = 11 (PDE) S-ITALY Seismic activity – Local Time M  5

Europlanet Graz, 1-2 June Case study – earthquakes Aegean Sea – M  5 n = 5 (PDE) Crete Aegean Sea vs. Crete Seismic activity – Local Time M  – M  5 n = 4 (PDE) Aegean Sea / Strongest events : UT= lat=36.31° long=23.21° d=66 km M=6.7

Europlanet Graz, 1-2 June Case study – earthquakes Aegean M  4, n = 956 (NOA) Ionian Is M  4, n = 237 (NOA) Gradient  H from IGRF10 AEGEAN vs. IONIAN IS Seismic activity – long term M  4

Europlanet Graz, 1-2 June Case study – earthquakes Ionian Is M  5, n = 36 (NOA) S-Italy M  5, n = 57 (INGV+PDE) S-ITALY vs. IONIAN IS Seismic activity – long term M  5

Europlanet Graz, 1-2 June Novel aspects  External sources – causing geomagnetic variations - strongly influence seismic activity (trigger)  Origins: solar radiation, ionosphere, Sq ; magnetic dynamo  Answer to daily rhythm of seismic activity (LT)  Monitoring the process: easy by geomagnetic observatories  Predictability: systematic diurnal, seasonal, secular variations (IGRF 2010)  Not yet investigated: influence of magnetic storms  Faster monitoring of variations by space observations ?

Europlanet Graz, 1-2 June Observations (1997) – long term Duma, Vilardo (INGV), 1998 n: annual number of eqs M  1.8, sf: annual number of solar flares (10 3 ) Duma, Vilardo (INGV), 1998 Mt. VESUVIUS volcanic eqs, area 10 x 10 km, 1.8  M  3.1, , 1400 events

Europlanet Graz, 1-2 June Tectonic settings & faulting mechanisms in Greece (Dewey et al., 1973 / A. Tzanis, UOA, 2003)

Europlanet Graz, 1-2 June Model of Sq telluric current vortex  Fits observed Sq-variations at observatories  Computes grad  H(LT)

Europlanet Graz, 1-2 June  H – current density

Europlanet Graz, 1-2 June The electromagnetic model  Magnetic observatories monitor horizontal force Fh C (t)

Europlanet Graz, 1-2 June Energy – diurnal variation  Sq: solar controlled, heating, ionization, tides (Chapman, Bartels, 1940)