Sun and Geosphere, 2015;

10: 127 -132

ISSN 1819-0839

Possible relationship between exogenous parameters and seismicity:
Ultra-Low Frequency (ULF) of Magnetic Pulsation, Pc
Jusoh Mohamad Huzaimy1,2, Mohd Kasran Farah Adilah1,2,
Ahmad Siti Noor Aisyah1,2, Huixin Liu3,4, K. Yumoto3,4, Mhd Fairos Asillam5,
Nyanasegari Bhoo Pathy5, Akimasa Yoshikawa4 and MAGDAS/CPMN Group4.
1

Faculty of Electrical Engineering, Universiti Teknologi MARA, Malaysia
Applied Electromagnetic Research Center, Universiti Teknologi MARA, Malaysia
3
Earth and Planetary Science, Graduate School of Sciences, Kyushu Universiti, Japan
4
ICSWSE, Kyushu University, Japan
5
National Space Agency (ANGKASA), Malaysia
2

E mail (huzaimy@salam.uitm.edu.my & farahadilah87@gmail.com).
Accepted: 8 September 2015
Abstract: The physical processes of transferring electromagnetic energy from sun to the earth can be referred as Solar –Terrestrial system. It involves terrestrial atmosphere, the outer part of geomagnetic field, and the solar events, which
influence them. To further investigate this coupling mechanism, we propose another exogenous source to be analysedwhich is cosmic ray. In this study, the investigation on possible relationship between geomagnetic ULF pulsation andseismicity due to exogenous parameters has been focused. Unlike other frequency range, ULF waves can propagate
through the crust and reach the earth surface, thus produce reliable precursors to large impending earthquakes. In thisanalysis, solar activity data were obtained from the Goddard Space Flight Center, NASA via the OMNIWeb Data Explorer
and the Space Physics Data Facility. Earthquake events were retrieved from the Advanced National Seismic System (ANSS)
database. The variability of horizontal component of the geomagnetic field at two different stations; Ashibetsu (Japan)
and Langkawi (Malaysia) extracted from Magnetic Data Acquisition System/Circum-pan Pacific Magnetometer Network(MAGDAS/CPMN) were investigated in order to study correlation between the local earthquake epicenter depth at northJapan and north Sumatera and the geomagnetic ULF pulsations. From the results, the significant correlations between
solar wind speed, ULF average amplitude (nT) and earthquake’s epicenter depth (km) was observed. Higher ULF
amplitude Pc 5 corresponds to the high solar wind speed (km/s) and deeper epicenter depth of localized earthquake.
© 2015 BBSCS RN SWS. All rights reserved
Keywords: Exogenous parameters; earthquake; geomagnetic data; Ultra-low frequency (ULF); epicenter depth

Introduction:
The extra-terrestrial – terrestrial relationship is acentral point in many research directions nowadays
and some extra-terrestrial – terrestrial relationships havealready been confirmed and have been incorporated
into several scientific areas (Kovalyov, M and Kovalyov,
S, 2015). Scientific research has also provided someevidence on the relation of solar – magnetosphericactivity with earthquakes. Different elements of solar
activity have been proposed as triggers of seismic
activity: solar and lunar tides (Jakubcova and Pick,1987), solar proton fluxes (Velinov, 1975), earthward
movement of the magnetopause caused by anincreased solar wind (SW) dynamic pressure(Makarova and Shirochkov, 1999), high SW speed(Sytinskii, 1989). The contribution of various solar impact
processes on earth’s lithosphere and their association
with the seismic event needs much work.
Electromagnetic (EM) waves in the ULF (ultra low
frequency) range extracted from ground observations
are considered as a promising method to monitor thecrustal activity (Yumoto, et al., 2009). In recent years
considerable work has been done based on groundand satellite observations to find convincing evidence
of EM responses during earthquake events (Gokhberg
et al., 1982; Molchanov and Hayakawa, 2008;
Hayakawa et al., 1996; Hayakawa and Molchanov,2002). In general, it has been found that out of thewide range of frequencies from ultra-low frequency(ULF) to high frequency (HF) range (0.001 Hz–30 MHz);the ULF band (0.001–10 Hz) is the only one which can
produce reliable precursors to large impending
earthquakes.
Dynamic processes in the earthquake preparation
zones can produce a current system, which canbecome local sources for the generation of EM fields in
different frequencies including ULF (Molchanov andHayakawa, 1995 and Hayakawa et al., 1999). The highfrequency waves are attenuated so rapidly that theycannot be observed on the earth surface, whereas ULF
waves can propagate through the crust and reach theearth surface. Therefore, the probability of earthquake
signature manifestations is much higher in the ULF
range than in other frequency ranges.
The preference of ULF band over others is based on
the fact that skin-depths of ULF waves cover all
expectedearthquake
sourcedepthsfromapproximately 5 to 200 km, depending on wave
period and the conductivity in the lithosphere. The
penetration
depth
increases
withdecreasing
underground conductivity. Due to this reason ULF
waves (geomagnetic pulsations, Pc 3–5 types) havebeen successfully used in magneto-telluric methods forremote sensing of the earth’s crust conductivity,

Special Edition “2015 UN/Japan Workshop on Space Weather”

127Jusoh Mohamad Huzaimy, et.al., Possible relationship between exogenous parameters and seismicity:…….

because any structural change in earthquake regions
can lead to a change in the crust resistivity which canaffect the behaviour of ground observed ULF fields.
To connect the exogenous parameters toseismicity, we have investigated the possibility ofground magnetic pulsations acting as one of thetriggering factors by using magnetic pulsation
measurements at Ashibetsu (Japan); for earthquakes
monitoring in north Japan and Langkawi (Malaysia);
for earthquakes monitoring in north Sumatra.

Aeronomy (IAGA) in Table 1. The raw data fromMAGDAS/CPMN stations was first bandpass-filtered
before we plotted the dynamic power spectra density
to identify the occurrences of ULF at Pc 3, Pc 4 and Pc
5.
The dependence characteristic of skin depth on
the ULF period in the lithosphere is tabulated in Table 2(Yumoto et al., 2009). Based on this table, we can seethat EM wave with longer time period is able topropagate deeper into the earth’s crust.

Methodology:

TABLE 1. IAGA classification of ULF waves in 1964

The concept involves the study of both extraterrestrial and terrestrial parameters. For this study, we
examined the extra-terrestrial parameters including
cosmic ray intensity, solar cycles (sunspot numbers)
and SW speed. The terrestrial parameters examined
are earthquakes at different magnitude and epicenter
depth (global and local events), and geomagnetic
pulsations.
Exogenous parameters and earthquake data
Cosmic ray intensity data can be obtained from
Neutron Monitor Database which is organized by
University of Oulu. Sunspot cycle in solar activities is awell-known parameter and often used by space
physics researchers to monitor the sun’s activities. In thisresearch, the values of sunspot numbers (SSN) fromMarshall Space Flight Center, NASA database(http://solarscience.msfc.nasa.gov/) were used toindicate different phases of solar cycle. These phases
reflect the activity of the Sun. While the parameters ofsolar activity data; sunspot number and SW speed
were obtained from the Goddard Space Flight Center,NASA via the OMNIWeb Data Explorer and the Space
Physics Data Facility.
The global earthquake events with magnitude 4.0
to 9.9 Richter scale from year 1963 to 2010 are
extracted from ANSS, hosted by Northern California
Earthquake
Data
Center(http://www.ncedc.org/anss/). The earthquakes are
selected based on the depth of epicenter less than
100 km to ensure the possible triggering factors fromexternal sources.
Geomagnetic data
Geomagnetic data are used in this study as amonitoring parameter for solar and seismicity coupling.
The data was extracted from MAGDAS/CPMN network
constructed by Prof. Yumoto. Two (2) stations involvedin this study are Ashibetsu (ASB) station in Japan andLangkawi (LKW) station located in Malaysia. The
MAGDAS/CPMN magnetometer is a ring core-type
fluxgate magnetometer that measures the threecomponents of the geomagnetic field; Horizontal
component (H), Declination component (D), and the
Vertical component (Z).
Ultra-Low Frequency (ULF) analysis
The 1-sec resolution data from horizontal
component were used to examine the geomagnetic
pulsations, Pc 3, Pc 4 and Pc 5 as classified byInternational Association of Geomagnetism and128

Continuous

Irregular

Period

Freq

(sec)

(mHz)

Pc 1

0.2-5

200-5000

Pc 2

5-10

100-200

Pc 3

10-45

22-100Pc 4

45-1506.7-22

Pc 5

150-600

1.7-6.7

Pi 1

1-40

25-1000

Pi 2

40-1506.7-25TABLE 2. Dependence of skin depth on the wave period of
the inducing fields and electric conductivity in thelithosphere (Yumoto et al., 2009)
Conductivity, σ (S/m)
Skin depth, δ (km)

sec

10-1

10-2

10-3

10

5.03

15.91

50.32

45

10.68

33.76

106.76

150

19.4

61.64

194.9250

87.18

275.66871.73150

150.99477.461509.88

T (period)min

Results and Discussion:
Relationship between cosmic ray intensity and solar
activity
To study the relationship between cosmic ray andsolar activity, the cosmic ray intensity, sunspot number
and SW speed during the solar cycle 23 and the latest
solar cycle 24 are plotted as in Figure 1 a),b) and c).
This figure indicates the anti-correlation between
cosmic ray cycle and solar cycle. During theascending and maximum solar cycle, the cosmic ray isdescending and at minimum cycle. Furthermore, highSW speed, Vsw with the speed more than 500km/s(remarked as in red box in Figure 1 c)) are observed
during descending and minimum solar cycle orascending cosmic ray cycle.

Special Edition “2015 UN/Japan Workshop on Space Weather”

Sun and Geosphere, 2015;

10: 127 -132

ISSN 1819-0839

total number of earthquake events at each sunspot
level which are categorized into 0-20, 20-40, 40-60, etc.
ranges of sunspot number. From Figure 3, we can seethat the largest number of shallow earthquakes isobserved at the lowest level of sunspot number below
20 with ~ 56,000 events in total. The number ofearthquakes decreases with increasing SSN until SSN
reaches 60. It then stays stable except for an increase
between 120 and 140 SSN. The same trend can also be
observed with earthquake events at epicenter depth
in between 40 to 100 km. The only difference is that the
total number of earthquake events is smaller than thatof shallow earthquakes.

Figure 1: 27-averaged exogenous parameters a) Cosmic rayintensity, b) sunspot number and c) SW speed

This finding highlights that higher tendency of highspeed SW occurs during the descending and minimumof solar cycle or ascending cosmic ray cycle. This is
supported by the study of Kovalyov, M and Kovalyov,
S, (2015) which reveals that there is a possibility that
other extra-terrestrial parameter which is cosmic ray
could influence the variation of solar activity.
Variation of earthquake occurrence and solar cycle
The percentage of earthquake event occurred at
different phases of solar cycle as shown in Figure 2, hasbeen plotted to study the possible relationshipbetween solar cycles (SSN) and earthquakes startingfrom the lowest earthquake magnitude (mag 4.0) to
the highest magnitude (mag 9.0). Four solar cycles arestudied from the year 1963 to 2009 which are solar
cycles 20 to 23. During this period of observation, we
can see earthquakes have higher tendency more than
60% to occur during minimum and descending phasesof solar cycle at all magnitude.
Overall, we can see more earthquakes tend tooccur around minimum and descending phases ofsolar cycle especially for greater earthquake
magnitudes. This trend confirms the results by
Gousheva et al., (2003) and Khain and Khalilov (2007),
which show that the earthquake at higher magnitude(M ≥ 7.0) corresponds better to solar activity.
Variation of earthquake epicenter depths with solar
cycle
We further examined the previous results by plotting
the number of earthquakes with respect to SSN during
the same period (solar cycles 20 to 23) as shown in
Figure 3 for the case of shallow (< 40 km) earthquakes
and Figure 4 for deeper earthquakes (40-100 km). Yaxis on the left panel represents the number of yearly
earthquake events and X-axis represents the yearlysunspot number. Y-axis on the right panel shows the

Figure 2: Percentage of earthquakes during different phases ofsolar cycles 20 to 23

Overall, more earthquakes seem to occur at lower
range of SSN. This result confirms the study by Tavares
et al. (2011). The field experiments observed by
Zeigarnik et al. (2007) shows that the number of shallow
earthquakes at epicenter depth between 5-25 km
occurred more frequently after the high power EM
pulses injected into the earth crust. This shows thepossibility of shallow earthquakes to be triggered byexternal sources. However, more investigations on
extra-terrestrial and terrestrial factors are needed toconfirm this expectation.
ULF: Relation between earthquake occurrence andepicenter depth (km)For this study, we have examined the statistics ofearthquake occurrences at different epicentre depths
for both regions. Figure 5 and Figure 6 show thenumber of earthquakes at different epicenter depth innorth Japan region during the year of 2005 and innorth Sumatra region during year the 2010,
respectively. We can see most earthquakes in bothregions occurred at around 30 to 60 km depth. By
assuming the lithosphere conductivity, σ is 10-2 S/mfrom Table 2, Pc 5 range at the period of 150 sec is thebest ULF wave to be associated with earthquakes inthese regions, as it has a skin depth of 61.64 km which issimilar to the epicenter depth.

Special Edition “2015 UN/Japan Workshop on Space Weather”

129Jusoh Mohamad Huzaimy, et.al., Possible relationship between exogenous parameters and seismicity:…….

Figure 3: Variation of yearly shallow earthquake event withrespect to sunspot number

Figure 5: Epicenter epth of North Japan region earthquake foryear 2005

Figure 4: Variation of yearly deep earthquake event with respect
to sunspot number

ULF: North Japan region
We have analysed the occurrence of earthquake
events within 150 km radius from the MAGDASAshibetsu (ASB) station, Japan from 15 August to 15
September 2005. During the period of analysis, 47
earthquake events were recorded. The earthquakes
with epicenter depth 60 km or less were selected andcompared with the SW speed, Vsw and average
amplitude of geomagnetic pulsation Pc 5. All of theparameters are plotted hourly throughout the periodof observation to precisely monitor the activities of Vsw,
Pc 5 and the number of earthquakes.
In Figure 7(a), we can see the variation of SW speedwith 4-peak trends varies from average speed 400 km/s
to 700 km/s. The pattern of solar wind speed can beclearly seen from the plotted trend-line. Figure 7(b)shows the geomagnetic pulsations Pc 5 extracted fromground magnetometer which gives the localized
reading of magnetic pulsation in the frequency rangeof 1.7-6.7 mHz (refer to Table 1 for detail classificationof ULF waves). From the plot, we can see clearly theaverage amplitude of Pc 5 varies between 0 to 2 nanoTesla (nT). The trend-line of Pc 5 shows a goodcorrespondence with that of the SW speed. Thisconfirms the studies by previous researchers that Pc 5 isa good index for SW speed (Baker et al., 2005 and Raeet al., 2005).
Figure 7(c) shows the epicenter depth ofearthquakes occurred during the same period.
Comparing with Figure 7(b), we can see the number ofearthquakes with epicenter depth of ~ 60 km follows

130

Figure 6: Epicenter depth of North Sumatra region earthquake foryear 2010closely the amplitude of Pc 5. This demonstrates thepotential connection between the two.
ULF: North Sumatra region
For this region, we have done a similar analysis tothe north Japan region but in a different time period tosee the correspondence of geomagnetic pulsation Pc
5 and earthquake occurrences in Sumatra region. The
observation of SW speed, geomagnetic pulsation Pc 5
and earthquake event shown in Figure 8 (a), (b) and(c) respectively was done during a 1-month period
from 12 March to 11 April 2010. The geomagnetic
pulsation Pc 5 was extracted from observations at
MAGDAS Langkawi (LKW) station, Malaysia.
By referring to Figure 8 (a), at first 100-hour ofobservation, the SW speed was 500 km/s before
decreasing and increasing in the next 200-hour period.
The SW speed later decreases smoothly and started toincrease again in the 300-hour period and reached its
peak at the end of 500-hour period with speed ataround 780 km/s. This SW speed variation corresponds
well with that of the geomagnetic pulsation Pc 5 asshown in Figure 8 (b). Throughout the observation
period, the average amplitude of geomagnetic
pulsation Pc 5 is around 2 nT. However, several events

Special Edition “2015 UN/Japan Workshop on Space Weather”

Sun and Geosphere, 2015;

10: 127 -132

ISSN 1819-0839

Hours of 15 August-14 September 2005
Figure 7: Variation of (a) SW speed, (b) amplitude of Pc 5 and (c)epicenter depth earthquake events from 15 August to 14
September 2005 for North Japan region.

of high Pc 5 amplitude at more than 2 nT wereobserved around 200-hour, the same period of SW
speed enhancement. The maximum value of average
Pc 5 amplitude with value around 7 nT was recordedat the end of 500-hour period, also at the same time
we observed the maximum SW speed. The trend-lines
for both plots show the similar pattern between them.
The epicenter depth of earthquake events which
occurred around this region was plotted in Figure 8 (c).
If we compare it with the average amplitude of Pc 5,
the number of earthquake events with epicenter
depth of ~ 60 km tends to occur more during higher
average amplitude of Pc 5. Two periods with theenhancement of earthquake events are during the first
200 hour where the average amplitude of Pc 5 washigh and during 600-hour period, around 50 hours after
the maximum average amplitude of Pc 5.
The three (3) observed parameters have a goodcorrespondence in tendency. It can be summarizedthat during the enhancement of SW speed, average
amplitude of geomagnetic pulsation Pc 5 tends toincrease as well and more number of earthquake
events with epicenter depth around 60 km occur.
The correlation of earthquakes with geomagnetic
pulsation Pc 5 for both regions; north Japan and north
Sumatra can be considered as promising, inagreement with several previous studies. The
observations of geomagnetic pulsations or ULF
anomalies related with earthquake events have beenreported in various, geologically distinct regions of the

Hours of 12 March-1 April 2010
Figure 8: Variation of (a) SW speed, (b) amplitude of Pc 5 and (c)epicenter depth earthquake events from 12 March to 11 April
2010 for North Sumatra, Indonesia region.

world (Fraser-Smith et al., 1990; Molchanov et al. 1992;
Kopytenko et al. 1993; Hayakawa et al. 1996).
On the other hand, the studies to relate SW speed
and pulsations have been done and established byprevious researchers. For example, Saito (1964) andSinger et al. (1977) showed that pulsation activity
correlates well with the SW speed. Later, several
authors (Greenstadt et al., 1977; Wolfe, 1980; Wolfe etal. 1985) showed that both the cone angle (the angle
between the IMF orientation and the Earth-Sun line)
and the SW speed control the occurrence and theamplitude of ground pulsations in the Pc 3 and Pc 4
range. Greenstadt et al. (1979) observed positive
correlations of magnetic pulsations Pc 3, Pc 4 and Pc 5
at Calgari and Leduc stations with SW speed.
The previous analysis demonstrates the possibility ofgeomagnetic pulsations as one of the parameter
connecting solar activity and seismicity.

Special Edition “2015 UN/Japan Workshop on Space Weather”

131Jusoh Mohamad Huzaimy, et.al., Possible relationship between exogenous parameters and seismicity:…….

Conclusion:

References

In recent years the study of solar activity and its
effects on the Earth’s tectonic activity has dramaticallyincreased. These works and results have indicated theSun’s pervasive influence on many geophysicalactivities of the Earth including earthquakes, volcanic
eruptions and global warming. This work examines therelation between solar activity and seismicity study byconsidering observations on global and local
earthquake events. In our attempts to explain thephysical mechanism of solar activity and seismicity, we
are focussing on geomagnetic pulsations extracted
from the ground magnetometer.
In this study, we consider geomagnetic pulsations
as one of the possible parameter to connect the solar
activity with seismicity. Since our analysis only focus on
the response of geomagnetic pulsation Pc 5, therefore,
to this stage, we could only conclude that it is possible
to consider geomagnetic pulsation Pc 5 as monitoring
parameter for earthquake event in a scope of solar
and seismicity coupling. The consideration on different
range of geomagnetic pulsations as monitoring
parameters definitely needs further analysis on thevarious earthquake events with different epicenter
depth at the diverse geological seismic regions.

Acknowledgement
This work was supported in part by JSPS Core-toCore Program (B. Asia-Africa Science Platforms),
Formation of Preliminary Center for Capacity Building
for Space Weather Research and International
Exchange Program of National Institute of Information
and Communication Technology (NICT).
We want to acknowledge Advanced National
Seismic System (ANSS) for providing a comprehensive
and updated earthquake database. Special thanks
are also dedicated to Space Weather Prediction
Center (SWPC) under National Oceanic andAtmospheric Administration (NOAA) and NASA for
providing the data of solar activity and IMF. This work isfinancially supported by Fundamental Research Grant
Projects, FRGS (Code No.600-RMI/FRGS 5/3(140/2014))
and Research Acculturation Collaborative Effort, RACE
(600-RMI/RACE 16/6/2(7/2014)). The authors would liketo thank Universiti Teknologi MARA for the
management support and consideration throughout
the project.

132

Baker, N. D.: 2005, Lecture Notes in Physics. 656, 993.
Fraser-Smith, A. C., Bernardi, A., McGill, P. R., Ladd, M. E.,
Helliwell, R. A. and Villard, O. G Jr.: 1990, GeophysicalResearch Letters. 17, 1465.
Gousheva, M. N., Georgieva, K. Y., Kirov, B. B., Atanasov, D.:
2003, in International Conference Proceedings of Recent
Advances in Space Technologies, (RAST ‘03), On the relation
between solar activity and seismicity, p. 236.
Greenstadt, E. W. and Olson, J. V.: 1977, Journal of GeophysicalResearch. 82, 4991.
Greenstadt, E. W., Olson, J. V., Loewen, P. D., Singer, H. J. andRussell C. T.: 1979, Journal of Geophysical Research. 84,
6694.
Hayakawa, M., Molchanov, O. A., Ondoh, T., and Kawai, E.: 2002,
J. Comm. Res. Lab., Tokyo. 43, 169.
Hayakawa, M. and Molchanov, O. A. Editors.: 2002, TERRAPUB,
477.
Hayakawa, M., Ito, T. and Smirnova, N.: 1999, GeophysicalResearch Letter. 26, 2797.
Jakubcova, I., and Pick, M.: 1987, Annals Geophysics. 5(B), 135.
Khain, V. E and Khalilov, E. N.: 2007, in Transactions of theInternational Academy of Science H&E, p. 217.
Kopytenko, Y.A., Matiashvili, T.G., Voronov, P. M., Kopytenko, E.
A. and Molchanov, O. A..: 1993, Physics of Earth andPlanetary Interiors. 77, 85.
Kovalyov, M and Kovalyov, S.: 2015, arXiv preprint arXiv:
1403.5728, 1.
Molchanov, O. A., Yu. A. Kopytenko, Voronov, P. M., Kopytenko,
E. A., Matiashvili, T. G., Fraser-Smith, A. C. and Bernardi,
A.: 1992, Geophysical Research Letters. 19, 1495.
Molchanov, O. A. and Hayakawa, M.: 1995, Geophysical Research
Letters. 22, 3091.
Molchanov, O. A., and Hayakawa.: 2008, TERRAPUB, Tokyo, 189.
Rae, I. J., Donovan, E. F., Mann, I. R., Fenrich, F. R., Watt, C. E.
J., Milling, D. K., Lester, M., Lavraud, B., Wild, J. A.,
Singer, H. J., Rème, H., and Balogh.: 2005, Journal ofGeophysical Research. 11.
Saito, T.: 1964, Report on Ionospheric Space Research, Japan. 18,
260.
Singer, H. J., Russell, C. T., Kivelson, M. G., Greenstadt, E. W.,
and Olson, J. V.: 1977, Research Letters. 4, 377.
Sytinskii, A. D.: 1989, Fizika ZemlIi. 2, 13.
Wolfe, A.,.: 1980, Journal of Geophysical Research. 85, 5977.
Wolfe, A., Meloni, A., Lanzerotti, L. J., and MacLennan, C. G.:
1985, Journal of Geophysical Research. 90, 5117.
Yumoto, K., Ikemoto, S., Cardinal, M. G., Hayakawa, M., Hattori,
K., Liu, J. Y., Saroso, S., Ruhimat, M., Husni, M., Widarto,
D., Ramos, E., McNamara, D., Otadoy, R.E., Yumul, G.,
Ebora, R., and Servando, N.: 2009, Physics and Chemistry of
the Earth, 360.
Zeigarnik, V. A., Novikov, V. A., Avagimov, A. A., Tarasov, N. T.
and Bogomolo, L. M.: 2007, in 2nd International Conference
on Urban Disaster Reduction, Discharge of Tectonic Stress inthe Earth Crust by High-power Electric Pulses for Earthquake
hazard Mitigation.

Special Edition “2015 UN/Japan Workshop on Space Weather”