MIS27-01

Room:201A

Time:May 26 15:15-15:30

Correlation between strandings of marine mammals at the Kashima-Nada beach andearthquakes
ORIHARA, Yoshiaki1∗ ; NODA, Yoichi2 ; NAGAO, Toshiyasu31

Dpt. of Phys., Tokyo Gakugei Univ., 2 Tierra Tecnica Ltd., 3 EQ Prediction Res. Center, Tokai Univ.

A mass stranding of Melon-headed whales (Peponocephala electra) occurred at the Kashima-Nada beach, Japan, seven days
before the 2011 M9.0 Off the Pacific coast of the Tohoku Earthquake (Tohoku EQ). Kashima-Nada beach is located 300 kmsouthwest of the epicenter. Some people said that the mass stranding might be a precursor of the Tohoku EQ. In this study, weperformed statistical analyses to determine the level of correlation between strandings at the Kashima-Nada beach and EQs. We
concluded that the mass stranding was not correlated with the Tohoku EQ.
Keywords: Stranding, Earthquake, Kashima-Nada, Geomagnetic disturbance

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MIS27-02

Room:201A

Time:May 26 15:30-15:45

Excitation mechanism and detection of electromagnetic pulses prior to earthquakes
TSUTSUI, Minoru1∗1Kyoto Sangyo University

We have been observing electromagnetic (EM) pulses generated by earthquake, and recently clarified behaviors of EM waves
excited by seismic waves, in which EM pulses can be easily excited due to piezo-electric effect in the earth crust by vibrations ofseismic S-waves [1]. On the other hand, we could not detect EM pulse at the rupture time of earthquake. Furthermore, even inlaboratory experiment, we could not confirm intense EM noise excitation in frequency ranges of MHz-kHz. Therefore we haveconcluded that EM pulse cannot be generated in the situations of cracking of earth crusts.
In order to clarify behaviors of EM pulses which would be excited prior to earthquakes. We speculated a generation mechanismof EM pulse in the earth that a kind of resonance in the earth crust by the vibrations of the seismic P-wave propagation in it isimportant. So we conducted a laboratory experiment in order to inspect EM radiation from crusts. The experimental setup
consists of ranging two granite pillars of 10 cm x 10 cm in cross section and 50 cm in length. A small glass ball is pinchedbetween the cross sections of interface of the ranging granite pillars. By increasing external pressure given to the cross sections
at the both ends of the ranging pillars, the small glass would be fractured. Then a negative stress impact is given to the interfaceof the ranging two pillars, and seismic P-waves propagate in the granites. EM pulse excited in the granite pillar due to piezo
electric effect can be radiated out. So the stress impacts and following seismic P-wave propagations in a crust with some scale
are key point for generating an EM pulse. We will show the experimental result.
Under the speculation based on the experimental result, we have been looking for the observation result. We finally found anEM pulse detected at about 7 hours prior to a rather large earthquake (M3.9), whose waveforms are similar to those obtained in
the laboratory experiment.
[1] Minoru Tsutsui, Behaviors of Electromagnetic Waves Directly Excited by Earthquakes, IEEE Geoscience and RemoteSensing Letters, Vol. 11, No. 11, pp. 1961-1965, 2014.

Keywords: observation of electromagnetic pulses, earthquake precursor, excitation mechanism

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MIS27-03

Room:201A

Time:May 26 15:45-16:00

Anomalous phenomena of Schumann resonances in possible association with earthquakes
HAYAKAWA, Masashi1∗ ; OHTA, Kenji2 ; IZUTSU, Jun2 ; NICKOLAENKO, A. P.3
1Hayakawa Inst. of Seismo Electromagnetics Co. Ltd., 2 Chubu University, 3 Inst. of Radio physics and Electronics, Ukraine

The anomalous behaviour in Schumann resonances was observed at a Japanese station, Nakatsugawa (geographic coordinates:
35.45 degree N, 137.3 degree E), which appeared as an enhancement in the fourth harmonic about one week before the 1999
Chi-chi earthquake (EQ) in Taiwan (Hayakawa et al., 2005). Schumann resonance is a global resonance phenomenon triggered
by global lightning activity in the tropic (Nickolaenko and Hayakawa, 2014). A mechanism to explain this anomaly has been
proposed with a model in terms of the wave interference between the direct ELF signal from one of the world-lightning centers
and that scattered by the seismo-ionospheric perturbation above Taiwan (Hayakawa et al., 2005; Nickolaenko et al., 2006). Thiscase study was extended statistically by using the ELF data observed at Nakatsugawa during 6 years (1999 to 2004) with specialreference to EQs in Taiwan (Ohta et al. (2006)). With the criterion of magnitude greater than 5.0, there were observed 33 EQs in
and around Taiwan, and the Schumann resonance anomaly is observed for 9 EQs (so that the anomaly percentage is 9/29 (because
no observation at Nakatsugawa due to some malfunction of the equipment for 4 EQs)). 29 EQs included 7 EQs in the land, whileother 22 EQs took place in the sea. As the result of analysis, anomalous Schumann resonances are observed for all inland EQs.
2 sea EQs from the 22, had the anomalous Schumann resonances, but these two EQs had the following characteristics: one was
the largest magnitude and the other the shallowest. This paper discloses the causative link between EQs in Taiwan and anomalous behaviour in Schumann resonance in Japan, and also suggests the land/sea asymmetry in generating the seismo-ionosphericperturbation closely associated with the mechanism of lithosphere-atmosphere-ionosphere coupling.
References
1. Nickolaenko, A. P. and M. Hayakawa, Schumann resonances for tyros, Springer, 2014.
2. Hayakawa, M., K. Ohta, A. P. Nickolaenko, and Y. Ando, Anomalous effect in Schumann resonance phenomena observedin Japan, possibly associated with the Chi-chi earthquake in Taiwan, Ann. Geophysicae, vol. 23, 1335-1346, 2005.
3. Ohta, K., N. Watanabe and M. Hayakawa, Survey of anomalous Schumann resonance phenomena observed in Japan, inpossible association with earthquakes in Taiwan, Phys. Chem. Earth, vol. 31, 397-402, 2006.
4. Nickolaenko, A. P., M. Hayakawa, M. Sekiguchi, Y. Ando, and K. Ohta, Model modifications in Schumann resonanceintensity caused by a localized ionosphere disturbance over the earthquake epicenter, Ann. Geophysicae, vol. 24, 567-575, 2006.

Keywords: Schumann resonance, earthquakes, Nakatsugawa observatory

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MIS27-04

Room:201A

Time:May 26 16:30-16:45

A statistical study for relationship between anomalous transmission of VHF band waves
and earthquakes at Hidaka area
MORITA, Shou1∗ ; MOGI, Toru1
1

Institute of Seismology and Volcanology, Hokkaido University

Electromagnetic precursors associated with the impending earthquake, such as variations of geoelectric current, total electron contents in the ionosphere, and anomalous transmission of radio waves in the VLF or VHF band, have been observed (ex.
Hayakawa, 1996). Recently, some researchers have discussed how these precursory phenomena relate statistically to the impending earthquake (Le et al., 2010; Orihara et al., 2012, Hattori et al., 2013, Han et al. 2014).
The observation of anomalous VHF-band radio-wave propagation beyond the line of sight prior to earthquakes is one of candidate method to predict an earthquake. It is considered that the anomalous propagation events were the result of scatteringof VHF-band radio waves in preparatory process of immediately prior to earthquakes occurring around the observation area
(Kushida and Kushida, 2002, Moriya et al.,2010). And, quantitative correlation between logarithm of the total duration of scattered wave transmission and the magnitude, or maximum seismic intensity has been proposed (Moriya et al., 2010).
Nevertheless, statistical relationship between anomalous radio wave intensities defined by clear threshold, and occurrence timeof impending earthquakes have not been investigated yet. We carried out statistical investigation by using received radio-wave
intensity data from a FM station beyond the line of sight between 1st January, 2012 and 31st December, 2013, observed at Erimo
observatory, Hokkaido. The sporadic E layer appears frequently in summer, and it affects to the anomalous transmission of FM
wave data. We removed the anomalous radio-wave intensity data affected by the sporadic E by the simultaneous appearance of
anomalous intensity at the other observatory far away.
During this period, we calculated the success rate (the ratio of number of intensity anomalies that an earthquake observed
within certain days to total number of intensity anomalies) and the alarm rate (the ratio of number of earthquakes that observed
intensity anomaly within certain days to total number of earthquakes) in case of earthquakes (M>3.0) that occurred at the epicentral distance with in the radius of 100km and 150km from the Erimo observatory.
As a result, the earthquakes M>4.5 that occurred within 100km from Erimo observatory showed higher the success rate thanthat of an random occurrence case. The maximum gain of the success rate between the present case and the random occurrencecase was obtained within 10 days after anomalous reception.
The results also indicated that the success rate by the anomalous radio-wave propagation was related with the earthquake(M>4) that occurs within 10 days with probability of approximately 30%.
We classified earthquakes occurrence into northern and southern area based on the latitude of the Erimo observatory, and considered success rate gains and alarm rate gains respectively. The results indicate that the gain is tend to be higher the earthquakes
occurring in northern area than the southern area.

Keywords: precursory phenomena, statistical study, success rate, alarm rate

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MIS27-05

Room:201A

Time:May 26 16:45-17:00

On the GPS-TEC and geomagnetic declination precursors
HEKI, Kosuke1 ; ENOMOTO, Yuji2∗
1

Department of Natural History Sciences, Hokkaido University, 2 Sinshu Advanced Science and Technology Center (SASTec)
Details will be elsewhere (Enomoto & Heki submitted in GJI)

Keywords: 2011Tohoku-Oki earthquake, ionosphere total electron content, geomagnetic declination, precursorb

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MIS27-06

Room:201A

Time:May 26 17:00-17:15

Statistical characteristics of the Ionsopheric TEC disturbances over Japan area
HONMA, Ayano1∗ ; HAN, Peng2 ; HATTORI, Katsumi2 ; LIU, Jann-yenq3
1

Faculty of Science, Chiba University, 2 Graduate School of Science, Chiba University, 3 National Central University, Taiwan

To reduce the effect of strong geomagnetic activities such as geomagnetic storms, the TEC data of 2 days after Dst index
exceed -60 nT were excluded in previous statistical studies of earthquake related TEC anomalies. Actually, the influences of amagnetic storm on TEC variations depend on the intensity and onset time of the storm. In this study, to clarify such dependences,
we applied classification analysis method to the storm data (Dst) and discussed the response of TEC variation to each type ofstorm.
We picked out all the 294 geomagnetic storms during 1998-2013, and classified them into 3 types according to its magnitude
and 4 types according to the onset time (local time). We checked the TEC data from 2 days before till 5 days after the onset ofeach geomagnetic storm. A bootstrap method (10000 times extraction) is used to calculate the average variation of the TEC foreach type of storm. The average variation can be regarded as an average response of TEC to the related type of storm. If theaverage value of TEC exceeds the mean±2σ threshold, we consider it being affected by the storm. By this mean, we could findthe accurate period affected by each type of storm.

Keywords: statistical analysis, geomagnetic storm, Ionsopheric TEC disturbances, bootstrap method, earthquake

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MIS27-07

Room:201A

Time:May 26 17:15-17:30

The role of earthquake source parameters in the subionospheric VLF/LF anomalies before
main shock
KAWANO, Tomoki1∗ ; TATSUTA, Kenshin1 ; HOBARA, Yasuhide1
1

Graduate School of Informatics and Engineering, The University of Electro-Communications

Although subionospheric VLF/LF anomalies have been observed for some of the major earthquakes, their generation mechanisms are still unclear. In this paper, we focus on the detailed earthquake source parameters such as centroid moment tensor(CMT) solution in addition to traditional earthquake magnitude and depth information to study the occurrence relationship between earthquake types and corresponding ionospheric anomalies. As a result, we found that the ionospheric anomalies areobserved prominently in association with thrust type earthquakes.
Keywords: ionospheric perturbation, VLF/LF transmitter, earthquake, CMT solution

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MIS27-08

Room:201A

Time:May 26 17:30-17:45

Statistical study of pre-seismic subionospheric disturbance observed by the DEMETER
and ground-based measurements
SUTO, Yushi1 ; TOGO, Shoho1∗ ; KAMOGAWA, Masashi1 ; BERTHELIER, Jean-jacques2 ; KODAMA, Tetsuya31

Dpt. of Phys., Tokyo Gakugei Univ., 2 LATMOS, France, 3 Earth Observation Research Center, Space Applications

The atmospheric and the ionospheric disturbance have been reported as an electromagnetic phenomenon related to the earthquakes in the 1980s. These phenomena have been expected to be useful for the short-term earthquake prediction. Motivated bythis background, we statistically investigate pre-seismic subionospheric disturbances by using the VLF electric field data of theDEMETER.
Keywords: Earthquake, Subionospheric disturbance, DEMETER

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MIS27-09

Room:201A

Time:May 26 17:45-18:00

Development of Early Warning System for Crustal Activity: Detection of Preparation
Process using Multiple-Observation
HATTORI, Katsumi1∗ ; HAN, Peng1
1

Graduate School of Science, Chiba University

New observations from ground and space have provided multiple evidences of pre-earthquake signals and the latest studies
show their statistical significance, repeatability, and universality. To understand the preparation process of large earthquakes
and slow-slip events in subduction zone, especially to clarify the nucleation stage of the earthquake cycle, we plan to establish
observation network in Boso, Japan, where large subduction earthquakes are expected soon. Since the subsurface fluid flow
may play an important role in the preparation process of subduction activities, we intend to employ electromagnetic approaches.
Geophysical monitoring such as ULF geomagnetic and geoelectrical observations, radon measurements, ocean bottom pressure
measurements, and inland GPS movements, will be incorporated to help to understand the preparation process and evaluate theapplicability of various pre-earthquake signals towards short term earthquake forecasting.

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