Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

Suaidi Ahadi, Nanang Tyasbudi Puspito, Gunawan Ibrahim, Sarmoko Saroso, Kiyohumi Yumoto, M. Muzli


Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007-2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake’s precursors, were determined by the Welch ratio SZ/SH at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the SZ/SH power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time.


Dst Index; earthquake precursor; polarization power ratio; quiet day; Sumatra; strong earthquake; ULF emission.

Full Text:



Kopytenko, Y., Ismaguilov, A., Voronov, V.S., Kopytenko, P.M., Molchanov, E.A., Hayakawa, O.A., Hattori, M. & Hattori, K., Magnetic Disturbances in ULF Range Connected with Seismic Sources, In: 2nd International Conference on Marine Electromagnetics – (MARELEC 99), France, pp. 435-445, 1999.

Hayakawa, M., Kawate, R., Molchanov, O.A. & Yumoto, K., Result of Ultra-Low Frequency Magnetic Field Measurements during the Guam Earthquake of 8 August 1993, Geophys. Res. Lett., 23(3), pp. 241-244, doi:10.1029/95GL02863, 1996.

Yumoto, K., Ikemoto, S., Cardinal, M.G., Hayakawa, H., Hattori, K., Liu J.Y., Saroso, S., Ruhimat, M., Husni, M., Widarto, D.S., Ramos E., McNamara, D., Otadoy, R.E, Yumul, G., Ebora, R. & Servando N., A New ULF Wave Analysis for Seismo-Electromagnetics using CPMN/MAGDAS Data, Phys. Chem. Earth, Parts A/B/C, pp. 360-366. doi:10.1016/j.pce.2008.04.05, May 2008.

Hattori, K., ULF Geomagnetic Changes associated with Large Earthquakes, Terr., Atmospheric and Oceanic Sci., 15, pp. 329-360, Sep. 2004.

Hattori, K., Serita, A., Yoshino, C., Hayakawa, M. & Isezaki, N., Singular Spectral Analysis And Principal Component Analysis for Signal Discrimination of ULF Geomagnetic Data associated with 2000 Izu Island Earthquake Swarm, Phys. Chem. Earth, 31(4-9), pp. 281-291, doi:10.1016/j.pce.2006.02.034, Feb. 2006.

Febriani, F., Han, P., Yoshino, C., Hattori, K., Nudiyanto, B., Effendi, N., Maulana, I., Suhardjono & Gaffar, E., Ultra Low Frequency (ULF) Electromagnetic Anomalies Associated with Large Earthquakes in Java Island, Indonesia by Using Wavelet Transform and DetrendedFluctuation Analysis, Nat. Hazards Earth Syst. Sci., 14, pp. 789-798, doi:10.5194/nhess-14-789-2014, Apr. 2014.

Mogi, T., Tanaka, Y., Widarto, D.S., Arsadi, E.M., Puspito, N.T., Nagao, T., Kanda, W. & Uyeda, S., Geoelectric Potential Difference Monitoring in southern Sumatra, Indonesia Co-Seismic Change, Earth Planet Space, 52, pp. 245-252, Feb. 2000.

Widarto, D.S., Mogi, T., Tanaka, Y., Nagao, T., Hattori, K. & Uyeda, S., Co-seismic Geoelectrical Potential Change associated with the June 4, 2000’s Earthquake (Mw 7.9) in Bengkulu, Indonesia, Phys. and Chem. of the Earth, 34, pp. 272-279, doi:10.1016/j.pce.2008.09.009, Oct. 2008.

Saroso, S., Hattori, K., Ishikawa, H., Ida, Y., Shirogane, R., Hayakawa, M., Yumoto, K., Shiokawa K. & Nishihashi, M., ULF Geomagnetic Anomalous Changes Possibly associated with 2004-2005 Sumatra Earthquake, Phys. Chem. Earth., 34, pp. 343-349, doi:10.1016/j.pce. 2008.10.065, Nov. 2008.

BMKG: kan.bmkg, 9 April 2012.

WDC, World Data Center for Geomagnetism:, 24 October 2013.

Cerrato, Y., Saiz, E., Cid, C. & Hidalgo, M.A., Geomagnetic Storms: their Sources and a Model to forecast the Dst Index, Lec. Notes and Essays in Astrophys, 1, pp. 165-176. 2004.

Molchanov, O., Schekotov, A.Y, Fedorov E., Belyaev, G. & Gordeev, E., 2003. Preseismic ULF Electromagnetic Effect from Observation at Kamchatka, Nat. Hazards Earth Syst. Sci., 3, pp. 203-209, doi:10.5194/ nhess-3-203-2003, Oct. 2002.

Scordilis, E.M., Empirical Global Relations Converting Ms and mb to Moment Magnitude, J. Seis., 10, pp. 225-236, doi:10.1007/s10950-006-9012-4, Jan. 2006.

Hirano, T. & Hattori, K., ULF Geomagnetic Changes Possibly associated with the 2008 Iwate-Miyagi Nairiku Earthquake, J. Asian Earth Sci., 41, pp. 442-449, doi:10.1016/j.jseaes.2010.04.038, Jun. 2010.

Han, P., Hattori, K., Huang, Q., Hirano, T, Ishiguro, Y., Yoshino, C. & Febriani, F., Evaluation of ULF Electromagnetic Phenomena associated with the 2000 Izu Island Earthquake Swarm by Wavelet Transform Analysis, Nat. Hazards Earth Syst. Sci., 11, pp. 965-970, doi:10.5194/ nhess-11-965-2011, Mar. 2011.

Molchanov, O.A., Generation of ULF Electromagnetic Emissions by Microfracturing. Geophys. Res. Lett., 22, pp. 3091-3094, doi:10.29/ 95GL00781, Nov. 1995.

Molchanov, O.A. & Hayakawa, M., On the Generation Mechanism of ULF Seismogenic Electromagnetic Emissions, Phys. Earth Planet, 105(3-4), pp. 201-210, doi: 10.1016/S0031-9201(97)00091-5, Jan. 1998.

Molchanov, O.A., Kopytenko, Y.A, Voronov P.M, Kopytenko, E.A, Matiashvili, T.G., Fraser-smith, A.C. & Benardi, A., Result of ULF Magnetic Field Measurement near the Epicenter of the Spitak (Ms=6.9) and Loma Prieta (Ms=7.1) Earthquake: Comparative Analysis, Geophys. Res. Lett., 19, pp. 1495-1498, doi:10.1029/92GL01152, Jul. 1992.

Hattori, K., Akinaga, Y., Hayakawa, M., Yumoto, K., Nagao, T. & Uyeda, S., ULF Magnetic Anomaly Preceding the 1997 Kagoshima Earthquake, “Seismo-Electromagnetics: Lithosphere-Atmosphere-Iono-sphere Coupling”, M. Hayakawa & O. Molchanov, eds., pp. 19-28, TERRAPUB, Tokyo, 2002.

Hattori, K., Han, P. & Huang, Q., Global Variation of ULF Geomagnetic Fields and Detection of Anomalous Changes at a Certain Observatory using Reference Data, Electr. Eng. Jpn, 182, pp. 9-18, doi:10.1002/ eej.22299, Nov. 2012.

Hattori, K., Han, P., Yoshino, C., Febriani, F., Yamaguchi, H. & Chen, C.H., Investigation of ULF Seismo-Magnetic phenomena in Kanto, Japan during 2000-2010: Case Studies and Statistical Studies, Surv. Geophys., 34, pp. 293-316, doi:10.1007/s10712-012-9215-x, Dec. 2012.

Ismaguilov, V.S., Kopytenko, Yu., Hattori, K., Voronov, P.M., Molchanov, O.A. & Hayakawa M., ULF Magnetic Emissions connected with Under Sea Bottom Earthquakes, Nat. Hazards Earth Syst. Sci., 1, pp. 23-31, doi:10.5194/nhess-1-23-2001, Jul. 2001.

Stranneby, D., Digital Signal Processing and Application, pp. 107-108, Elsevier, 2001.

McCloskey, J., Lange, D., Tilmann, F., Nalbant, S.S., Bell A.F., Natawidjaja, D.H. & Rietbrock, A., The September 2009 Padang earthquake, Nature Geosci, 3, pp. 70-71, Jan. 2010.

Wiseman, K., Banerjee, P., Burgmann, R., Sieh, K., Dreger, D.S. & Hermawan, I., Source Model of the 2009 Mw 7.6 Padang Intraslab Earthquake and Its Effect on the Sunda Megathrust, Geophys. J. Int., 190, pp. 1710-1722. doi:10.1111/j.I365-246X.2012.05600.x, Dec 2011.

Lay, T., Ammon. C.J., Kanamori, H., Yamazaki, Y., Cheung, K.F. & Hutko, A.R., The 25 October 2010 Mentawai Tsunami Earthquake (Mw 7.8) and The Tsunami Hazard Presented by Shallow Megathrust Ruptures, Geophys. Res. Lett., 38(L06302), pp. 1-5, doi:10.1029/ 2010GL046552, Mar. 2011.

Kon, S., Nishihashi, M. & Hattori, K., Inospheric Anomalies Possibly associated with M ≥ 6.0 Earthquake in Japan Area during 1998-2010: Case Studies and Statistical Study, J. Asian Earth Sci., 41, pp. 410-420, doi:10.1016/j.jseaes.2010.10.005, Oct. 2010.

Wang, T., Zhuang, J., Kato, T. & Bebbington, M., Assessing the Potential Improvement in Short-Term Earthquake Forecasts from Incorporation of GPS Data, Geophy. Res. Lett., 40, pp. 1-5, doi:10.1002/grl.50554, May 2013.

Molchan, G.M., Structure of Optimal Strategies of Earthquake Prediction, Tectonophys., 193, pp. 267-276, 1991.



  • There are currently no refbacks.

View my Stats

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.


ITB Journal Publisher, LPPM ITB, Center for Research and Community Services (CRCS) Building, 6th & 7th Floor, Jalan Ganesha 10, Bandung 40132, Indonesia, Phone: +62-22-86010080, Fax.: +62-22-86010051; E-mail: