Prediction of Ionospheric Precursors of Earthquake by Use of LFM

Ionosondes

Nathan Blaunshtein, Prof., DScBen Gurion University of the Negev

Israeli Seminar on Seismic Phenomena Tel Aviv University, January 27, 2010

Strategy of Prediction of IonosphericPrecursors of Earthquake

* At the present time the strategy of short-term prognosis of earthquakes consists of using the whole set of critical parameters, the precursors of the earthquake, including the magnetosphere, ionosphere, troposphere and the Earth’s crust.

* The three-decade researches show (Michael Gohberg, Yurii Galperin, Sergey Pulinets, Russia; Nathan Blaunshtein, Eugeniu Plohotniuc, Moldova-Israel; Masashi Hayakawa, Oleg Molchanov, Japan; J. Y. Liu, Taiwan; Bodo Reinisch, USA) that in the processes of earthquake preparation several days before the event there appear perturbations of different types not only in immediate proximity to the epicenter, but also in the heights of the lower and upper ionosphere.

Investigations of the Perturbed Ionosphere during 80th -90th

and during the First Decade of 2000th

* A close correlation between ionospheric plasma density disturbances and seismic events was shown:

At the end of 80th this correlation was shown by Drs. Michael Gokhberg, YuriiGalperin, Sergey Pulinets, from Institutes of Earth, Cosmic Space, IZMIRAN (Russia), respectively, by ionospheric stations and satellite observations.

In Taiwan, Profs. J. Y. Liu, Bodo Reinisch, and Dr. Sergey Pulinets had observed in period of 1995-1997 a close correlation with sporadic ionospheric layers observed two days before earthquake and the corresponding seismic event. Then, the same phenomena, in period of 2003-2006, have been observed by Prof. Liu in Taiwan.

In Japan, at end of 80th, Prof. Masashi Hayakawa and Dr. Oleg Molchanov have found low-band electromagnetic radiation and its interaction with cold ionosphericplasma.

At the beginning of 90th and then during period from 2004 to 2008, this correlation was shown by Profs. Nathan Blaunshtein, Eugeniu Plohotniuc (Moldova), ValeriiUryadov and Vladimir Shumaev (Russia) , using ionosondes, vertical and oblique.

Location of the Radio Observatory Near Vrancha Region

Investigations of the Perturbed Ionosphere in period of 90th above Vrancha Region

* Preliminary Experiments (1990 - 1992) curried out in Moldova

Were used:

Broadcasting stations with radio path covered the Vrancha Region (Romania): Bucharest-Dundushani (location of the observatory at the north of Moldova), passing above the Vrancha epicenter.

Budapest-Dundushani, Moscow-Dundushani and others area there are not above the Vrancha ranges (see the next page).

Investigations of the Perturbed Ionosphere in period of 90th above Vrancha Region

* Were found:

Irregular “flashes” of broadcasting signals, operating at hundreds of kHz to few MHz, and passing through the disturbed ionosphere were observed 3-4 hours before the seismic event.(magnitude of earthquake is M=5.8)

Sharp fading of receiving signal amplitude were observed 3-4 hours before the seismic event

An typical example of fading

Modern Method of Investigation of the Perturbed Ionosphere in period of 90th above Vrancha Region using Ionosondes

View of LFM Ionosonde

LFM Ionosonde PrinciplePrincipe of functioning

The instantaneous frequency f of this signal linearly varies with time:

Basic equation

,2

,2

)],2(exp[)( 2⎥⎦⎤

⎢⎣⎡−∈⋅+⋅=

TTttftfjata oo &ππ

ii fF τ.

=

dtdff =&

were f0 is the initial radiation frequency;

is the frequency change rate;

a0 is the signal amplitude;

T is the pulse duration.

tfff ⋅+= &0

For each ray i with different delay time is correspondent own differ frequencyiτ

Liner frequency modulation (LFM) mechanism:

The Reflected Signals Presentation

Examples of Ionograms Observed by LFM Iononosonde

Inskip (Great Britain) Unknown StationFinland

Sporadic Layers Observed by LFM Ionosonde 24 hours before Eathquake above Vrancha Region (M=6.1)

Sporadic Layers Observed by Pulse Ionosonde 2 Days before Eathquake above Taiwan

The same anomalous effect was observed by Prof. J. Y. Liu, Dr. S. Pulinets and Prof. B. Reinischduring the period of 1995-1998 for 14 earthquakes with M>5 above the Taiwan area.

One of the example of observations of the ionosphere during two days before seismic event occurring on May 11, 1998 in Taiwan area is shown here for M=5.8.

The same results were obtained during the period of 2003-2006 above the Taiwan area.

Thank You for your attention!21.04. 09 22.04. 09 23.04. 09 24.04. 09 25.04. 0920.04. 09

f, MH

z

17

15

13

11

17

15

13

11

26.04.09 27.04.09 28.04. 09 29.04. 09

0 4 8 12 16 20 24 UT

Before than 2 days from the seismic event with magnitude M=5.6 on 25.04.2009 was observed increase of MUF at 2-4 MHz with respect to other days observed during 20-23.04.2009.

New Anomalous Effects Observed in Vrancha Regionon 25.04.2009 (from 18:18 to 18:23 UT) using LFM Ionosonde

seismic event

SUMMARY

* The proposed technique based on LFM ionosondes by use sounding of the perturbed ionosphere with chirp signals allows for realization the following function:

1) Separation signal and noise by use of LFM ionosonde and the corresponding signal processing;

2) Full reconstruction of signal reflected/scattered from the ionosphere;3) Estimation ratio signal/noise;4) Precise observation of small-scale perturbations of the ionospheric plasma

and investigation of their “thin” effects;5) Differentiation of natural- and seismic-induced plasma irregularities

in the ionosphere both in the time and frequency domains.

* The above technique and the corresponding facility based on a network of two-three LFM ionosondes for sounding data processing can be used as a precise training network for ionospheric precursors prediction, such as time of future event, location of the epicenter and the magnitude of earthquake (see next transparency).

SUMMARY (Cont.)

NdN /

o3o2o1o0o1−o2−o3−

RE

TE

o6

o24

0

75 0 75 150 225 300 KM

9.44.21.10

1.14.29.4

9442110114294

10=

α

16.3=

α

T R

Monitoring of the ionosphere

Anomaly?

Measure

Estimate

Magnitude M

No

Yes

dATesting algorithm has several steps:

1. Estimation of 2. Estimation of deviations of AGW.3. Estimation of magnitude M.4. Estimation of area consisting maximum

perturbations of plasma density.5. Estimation of time before the seismic

event by analyzing of the corresponding ionograms.

NdN /

Predicting accuracy increaseswith increase of M and achieves90% for M>5.