MIS03-P01

Japan Geoscience Union Meeting 2016

Earthquake-induced electromagnetic field due to electrokinetic effect*Yongxin Gao1, Hengshan Hu2, Xiaofei Chen3
1.School of Civil Engineering, Hefei University of Technology, Hefei, China, 2.Department of
Astronautics and Mechanics, Harbin Institute of Technology, Harbin, China, 3.School of Earth andSpace Sciences, University of Science and Technology of China, Hefei, China
Electromagnetic fields generated by earthquake events were usually reported and have drawn a lot of
attentions. They can be detected before, during and after the seismic arrivals after earthquake
rupture started, and are referred to as the co-rupture, coseismic and post-seismic EM signals,
respectively. The co-rupture EM signal is of great importance since it arrives earlier than theseismic waves, especially the destructive shear and surface waves and has potentials in earthquake
early warning and hazard reduction. The coseismic EM signal arriving simultaneously with theseismic waves are also valuable since it contains the information of the subsurface medium in thevicinity of the EM sensors. However, how these kind EM signals are generated is still
controversial. Several possible mechanisms have been proposed to explain the earthquake-induced EM
signals, e.g., the electrokinetic effect, the piezoelectric effect, the motional induction effect,
etc.
In this study, we present the theoretical simulations of the earthquake-induced EM signals on thebasis of the electrokinetic effect. This result shows that due to the electrokinetic effect theearthquake can generate co-rupture EM signal, which arrives immediately after the onset of theearthquake and much earlier than the seismic arrivals. It arrives at different EM sensors
simultaneously. The earthquake can also generate coseismic EM field which arrives simultaneouslywith the seismic waves. Besides, our simulations indicate that when the earthquake fault rupturing
stops and the seismic waves pass far away, the magnetic field vanishes while the electric fieldnear the fault remains, decaying slowly and lasting for hundreds of seconds. The near-fault
poseismic electric fields hold similar features to some field observations in literature. We apply
our theoretical simulations to explain the coseismic EM data observed during the 2004 Mw6 Parkfield
earthquake. By using a finite fault source model obtained via kinematic inversion, we calculate theelectric and magnetic responses to the earthquake rupture are calculated. The result shows that thesynthetic electric signals agree with the observed data for both amplitude and wave shape,
especially for early portions of the records after the earthquake. Our simulations supports theelectrokinetic effect as the reasonable mechanism for the generation of the earthquake-induced
electric fields.
This work is supported by the National Natural Science Foundation of China (grants 41474038 and41204039).
Keywords: earthquake, electromagnetic fields, electrokinetic effect©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P01 -MIS03-P02

Japan Geoscience Union Meeting 2016

Detection of precursory anomalies using the four -component borehole strain meter (SKZ-1)
Xiangyang Kong1, Kaizhi Su2, *Yukio Fujinawa3, Yoichi Noda4
1.Earthquake Administration of Shandong Province, China, 2.Institute of Crustal Dynamics, CEA,
China, 3.Mieruka Bousai LtdEarthquake Administration of Shandong Province, China, 4.Tierra Tecnica
High sensitive crustal monitoring has a long history to investigate anomalous precursory variationsof earthquakes by means of several kinds of sensors as borehole volumetric sensors (Sacks andEvertson,1971), borehole extension sensor by Gladwin (1984), three component volumetric strain
meter by Sakata (2004) and Ishii and Yamauchi (2007). In China the four component strain meter withhigh performance was developed by Su Kaichi (1977) and has been used in earthquake-prone provinces
since 2006.The configuration of four sensing units at intervals of 45 degree provides a simple
indicator (consistent factor) of the sensor functioning and regime of the crust assumed to be plain
strain in normal state to detect candidates of anomalous variation without little ambiguities. The
observation at ten sites in several provinces of China for some 10 years has proved profitableperformance of the sensor: high stability and high degree of resolution to detect local andregional anomalous variations near hypocenter. In the normal stage the variations consist of steady
diurnal variations due to earth tide, steady trends due to the crustal stress adjustment after
construction of the borehole, and installment of the sensors. There are little urban noises withthe result of the consistent factor being almost constant value of 0.99.
Here we present analyses of anomalous variations detected by use of the correlation coefficient of
two independent plain strain components before two major earthquakes near the network: YiLiang
M5.7earthquake and LuDian M6.5 earthquake. In the imminent sage of the Yiliang earthquake, obvious
strain anomalies with periods of several days, several weeks appeared simultaneously in four
components at the nearest YiLiang site of the epicenter distance15.5km. The correlation
coefficients for those anomalies are well below reaching 0.2 compared with the ordinal value 1.0.
At DaGuan site of larger distance 30km, there appeared no significant anomalies with the factor
remaining the normal value near 0.99 or so. Analyses show that the correlation coefficient can beused to objectively detect anomalies to define the successive stage of earthquake occurrence fromnormal to relaxation stages.
A multiple observations using the four component strain meters, groundwater meters andelectromagnetic sensor are expected to substantially contribute to investigation of the nucleation
process of natural earthquakes. Present finding may contribute to efficient data analysis to detect
candidate of anomalies from using big amount of continuous multiple data with higher sampling rate.
Keywords: strain meter, pre-seismic anomalies, detection method©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P02 -MIS03-P03

Japan Geoscience Union Meeting 2016

Development of radon detector for atmosphere*Kiyotaka Ninagawa1, Isao Yamamoto, Tohru Okabayashi2
1.Department of Applied Physics, Okayama University of Science, 2.Department of Medical Risk andCrisis Management, Chiba Institute of Science
An increase of the radon in underground water at Nishinomiya City1 and an increase of the radon inatmosphere2 at the southern part of Hyogo Prefecture earthquake in 1995 were reported. Moreover, inthe case of Tohoku Region Pacific Coast Earthquake, the data of the exhaust air monitor in theradiation facility of Fukushima Medical College (Fukushima) has been reported that the peak
duration was long, and the peak decreased rapidly before the earthquake3.
We had measured radon concentration in a pit of Kurashiki mine, and in the atmosphere in Chiba
Prefecture, Chiba. We used a Radon Monitor of SUN NUCLEAR Corporation, Model 1028 in the Kurashiki,
and Pylon Trace Environmental Level Radon Gas Detectors (abbreviated to TEL) in Chiba. The TEL is
composed of ZnS(Ag) scintillator and a Photomultiplier. Its output spectra have continuous
distribution. Then counts depend on discrimination level, and have sometimes shift of backgroundcounts. On the other hand PIN photodiode have been developed for high sensitive radon detector, andused in Super-Kamiokande4. This time we produced a usual detector of atmospheric radon, using PIN
photodiode.
We use a Si PIN photodiode, S3204-09 (Unsealed), supplied by Hamamatsu Photonics K.K. We
constructed a radon detection system, using a stainless pot as air container, H4083 as charge
amplifier, C4900-01 as High voltage power supply module, 4419 (CLEAR-PULSE) as Pulse shapeamplifier, MCA-Lite (Laboratory Equipment Corporation) as Multi Channel Analyzer and a Personal
computer as data analysis. Output of the multi-channel analyzer showed clear alpha peaks of 218Po
and 214Po of radon daughters from Uranite. However, the Si PIN photodiode showed peak large shift.
It were overcome by coating surface of white ceramic with carbon tape. We introduced atmosphere to
the PIN photodiode, using air pomp, flowmeter and silica gel for dehumidification. It showed same
peaks of radon daughters, and we observed daily alteration of their intensity.
References
1) Igarashi G., Saeki T., Takahata N., Sano Y., Sumikawa K., Tasaka S., Sasaki Y. and Takahashi M.:
Groundwater radon anomaly before the Kobe earthquake, Science, 269, 60-61, 1995
2) Yasuoka, Y. and Shinogi, M.: Anomaly in atmospheric radon concentration: a possible precursor of
the 1995 Kobe, Japan, earthquake. Health Physics, 72, 759-761, 1997
3) Nagahama H., Yasuoka Y., Suzuki T., and Homma Y.: Radon Variation in the Air Before the 2011
Tohoku Earthquake (Mw =9.0), Programme and Abstracts, A32-09, The Seismological Society of Japan.
2011, Fall Meeting.
4) Nemoto, M., Tasaka S., Hori H., Okumura K., Kajita T., and Takeuchi Y. : Development of HighSensitive Radon Detector with Electrostatic Collection. Radioisotopes, 46, 710-719, 1997
(Japanese)
Keywords: Radon detection, atmosphere, earthquake©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P03 -MIS03-P04

Japan Geoscience Union Meeting 2016

Observational study of atmospheric electricity parameters(atmospheric electricity field(AEF), atmospheric ion concentration (AIC), and radon concentration) at Asahi, Boso
Peninsula, Japan*Junpei Omura1, Peng Han2, Chie Yoshino2, Katsumi Hattori2, Michikuni Shimo3, Toshiharu Konishi4
1.Department of Science, Chiba Uiversity, 2.Graduate School of Science, Chiba University, 3.Fujita
Health University, 4.OHYO KOKEN KOGYO CO.,LTD.
The total electron content anomaly preceding the large earthquake is one of the most promisingprecursory phenomena in the upper atmosphere. Lithosphere–Atmosphere -Ionosphere coupling (LAI
coupling) model has been proposed to explain the earthquake-related phenomena in the atmosphere andionosphere. We evaluate the possibility of chemical channel of LAI coupling through the monitoringof atmospheric electricity parameters such as the atmospheric electricity field (AEF), atmospheric
ion concentration (AIC), and radon concentration. In this paper, we will report about the propertyof atmospheric electricity parameters observed at Asahi station (ASA), Boso Peninsula, Japan. AIC,
AEF, atmospheric radon concentration, radon exhalation quantity from the ground, and weather
elements have been observed at ASA. First, we compare seasonal variation, daily variation, andresponse to precipitation of atmospheric electric parameter observed at ASA and those at Kiyosumi
station (KYS).
Variations of AIC and AEF before precipitations are quite similar at both stations; AIC increases
quickly when a precipitation starts and AEF begins to be disturbed three hours before rain starts.
But the variations after stopping precipitation have individual properties. Both parameters keephigh values for a few hours at ASA and it takes longer than KYS to back to the normal level. Daily
variation in each season also differs in each site. In summer, AIC takes minimum value at 15:00 LT.
in the daily variation at ASA. But at KYS, it takes maximum value at 15:00 LT. In winter, AEF
decreases from 09:00 LT to noon and gradually increases in daily variation. In other seasons, ittakes maximum value at 20:00 LT and fluctuated in relatively large range. Daily variation of AEF in
winter is mostly similar to the typical daily variation at KYS for all season.
Radon exhalation quantity variation has a clear negative correlation with 3 hours delay to the airpressure variation. Each season differs in daily pattern. AIC and AEF variations show lag
correlation with radon exhalation quantity variation. To extract anomalous radon variation related
to earthquakes, we should set a network of Radon monitoring and establish a model of radon
variation for the future detailed analysis.
Keywords: Lithosphere–Atmosphere -Ionosphere coupling, atmospheric ion concentration, atmosphericelectricity field, Radon exhalation quantity©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P04 -MIS03-P05

Japan Geoscience Union Meeting 2016

Multi-parameter satellite geochemistry for validation of atmospheric pre-earthquake
signals associated with major seismicity. Case study for Xinjiang, China and Baja,
California*Dimitar Ouzounov1, Yeju Cui1,2, Nikolaos Hatzopoulos1
1.Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of
Science & Technology Chapman University, Orange, California, USA, 2.Institute of Earthquake
Science, China Earthquake Administration, Beijing, China
We are presenting the development of satellite geochemistry for multi-sensor validation ofshort-term atmospheric phenomena preceding major earthquakes. The purpose of this study is to
explore the synergetic physical link between (1) satellite thermal infrared radiation (STIR) withanomalous distribution main trace gases :(2) Carbon dioxide (TCCO2), (3) Ozone (TCO3), (4) Methane(TCCH4) and (5) carbon monoxide (TCCO), associated with major seismicity. The science rationale formultidisciplinary analysis is based on concept Lithosphere-Atmosphere-Ionosphere Coupling (LAIC)(Pulinets and Ouzounov, 2011), which is based on the gas emission from the lithosphere during theearthquake generation and explains the synergy of different processes and anomalous variations,
usually named short-term pre-earthquake anomalies. We analyzed retrospectively several major
earthquakes in two deferent seismo-tectonic regions: XinJiang province in China and in Baja,
California including M7.2 of March 20, 2008 in China and M7.3 of April10, 2010 in Baja bysystematically analyzing multi-sensor satellite atmospheric chemistry and ground temperature/humidity observations. Meteorological satellite data include NOAA POES and AQUA/AIRS polar orbit
satellites. In both cases satellite data shows (STIR, TCCO2, TCO3, TCCH4, TCCO) building
atmospheric anomalies 1-20 days before the main shock. This probably is connected with enhances ofthe degassing rate of the lithosphere, which can provide additional source for flux emission near
major faults in the area. The hourly in-situ atmospheric observation show similarly in the airtemperature increases and drop in the relative humidity, probably as result of additional
atmospheric ionization observed before the three earthquake events. Our initial results suggestthat systematic use of multi-parameter satellite geochemistry can be used for additional physicalvalidation of pre-seismic processes associated with the major earthquake events.
Keywords: earthquake precursor, forecasting, satelite, geochemistry, radon©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P05 -MIS03-P06

Japan Geoscience Union Meeting 2016

A statistical investigation of z test on seismo-ionospheric anomalies in TEC associatedearthquakes in Japan during 1999-2014*AiLing Shih1, Jann-Yenq Liu1
1.National Central University
Statistical analysis on seismo-ionospheric precursors (SIP) by using global ionosphere map (GIM) of
the total electron content (TEC) in associated with 188 M≥6.0 earthquakes in Japan during
1999-2014. Various references days of -15, ±7, ±15, ±30 days to the earthquake are employed to findcharacteristics of SIP. Results show that both decrease (or negative) and increase (or positive)
anomalies in the GIM TEC before the earthquakes are further examined by z test. The receiver
operating characteristic curve is also applied to see whether the SIPs exist in Japan.
Keywords: earthquake, ionosphere©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P06 -MIS03-P07

Japan Geoscience Union Meeting 2016

3D Structure of Ionospheric Disturbances Related to Large Earthquakes*Mustafa Yagmur1, Shinji Hirooka1, Katsumi Hattori1
1.Chiba University
In this paper we have investigated the geomagnetic storms and Earthquake-related ionosphericdisturbances. Following geomagnetic storms, the ionospheric peak electron density (Nmax) and total
electron content (TEC) often increase or decrease very much from their quiet-time levels. These
increase/decrease are known as positive and negative ionospheric storms. This paper deals with someextremely significant geomagnetic and Earthquake-related events in between 2000 and 2013 which
involving positive and negative ionospheric variations having immense importance to space weather,with reference to TEC maps derived from a dual-frequency GPS receiver network (GEONET: GPS Earth
Observation Network) built by the Geospatial Information Authority of Japan (GSI), as well as foF2
and hmF2 (maximum electron density height) derived from four ionosonde observatories in Japan and
GNSS-RO data from COSMIC mission of NOAA/NSPO(USA-Taiwan joint mission). For comparison anddiscrimination of stormy and large Earthquake days, a 3D Structure of Ionosphere will be discussed
in the presentation.
Keywords: Tomography, Ionospheric Disturbances, Geomagnetic Storms, Earthquakes, TEC©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P07 -MIS03-P08

Japan Geoscience Union Meeting 2016

Assessment of Ionospheric TEC anomaly before large earthquake: Elimination of geomagnetic
storm effects*Katsumi Hattori1, Peng Han1, Shinji Hirooka1
1.Department of Earth Sciences, Graduate School of Science, Chiba University
The detection of electromagnetic perturbations prior to large earthquakes has been proposed as a
useful way to monitor the crustal activities. One of the most promising candidates is themeasurement of Total Electron Content (TEC). There have been many reports on TEC anomaly associatedwith large earthquakes from different parts of the world. To verify the relation between TEC
anomalies and seismicity around Japan, statistical studies by superposed epoch analysis have been
carried out. The results have indicated that before a M>6 earthquake there are clearly higher
probabilities of positive TEC anomalies in Japan. These results indicate the correlation between
TEC anomalies and sizeable earthquakes. Furthermore, by making use of long-term TEC data over Japan
during 2000-2013 and applying Molchan’s error diagram, we can evaluate the optimal parameter forearthquake forecasting. The results show that the TEC data contain potentially useful information
on earthquake forecasts.
Further research on earthquake forecasting and promoting its utilization will greatly contribute todisaster risk reduction. By using an interdisciplinary or integrated approach, which connects
science with technologies related to the ongoing earthquake forecast researches such as ULF
geomagnetic and GNSS methods, earthquake forecasting will be demonstratively realized.
Keywords: Ionospheric TEC anomaly, statistical studies, Molchan’s error diagram©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P08 -MIS03-P09

Japan Geoscience Union Meeting 2016

Statistical Analysis on ULF magnetic anomaly and local seismicity around Kakioka, Japan*Rui Du1, Katsumi Hattori1, Peng Han1
1.Graduate School of Science, Chiba University
To clarify and verify the ultra-low frequency (ULF) seismo-magnetic phenomena, we have performed
statistical studies on the geomagnetic data observed at the Kakioka (KAK) station, Japan, during
2001-2010. We investigated the energy of ULF geomagnetic signals of the frequency around 0.01Hz
using wavelet transform analysis. To minimize the influences of artificial noises and global
geomagnetic perturbations, we used only the geomagnetic data observed at nighttime (LT 2:30 am-4:00
am) and exclude the geomagnetic anomalies when the energy of horizontal component is large.
Statistical results of superposed epoch analysis have indicated that ULF magnetic anomalies are
more likely to appear before sizeable earthquake events (Es>108) rather than after them, especially
6-10 days before the events.
Finally, we have evaluated the precursory information of ULF geomagnetic signals for local sizeable
earthquakes using Molchan’s error diagram. We also compared our results with previous statisticalstudies at KAK. The above results have indicated that the ULF seismo-magnetic phenomena at KAK
clearly contain precursory information and have a possibility of improving the forecasting of large
earthquakes.
Keywords: ULF seismo-magnetic phenomena, statistical study, superposed epoch analysis (SEA),
Molchan’s error diagram©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P09 -MIS03-P10

Japan Geoscience Union Meeting 2016

The self-potential variation induced by groundwater flow and the self-potential tomography*Tomohiro Yamazaki1, Katsumi Hattori1, Tomomi Terajima2
1.Depart of Earth Sciences Faculty of Science , Chiba University, 2.Disaster Prevention ResearchInstitute, Kyoto University
Landslide is one of the most severe natural hazards in the world and there are two types;
rainfall-induced landslides and landslides triggered by an earthquake. To understand rainfallinduced landslide process by the self-potential approach, we struggle with the integrated research
to clarify the coupling among hydrological, geotechnical, and electromagnetic changes. Our final
goal is to develop a simple technology for landslide monitoring/forecasting using self-potential
method. The previous laboratory experiments show that the self-potential variation has arelationship with the ground water condition and soil displacements. So, in this paper, we first
demonstrate the numerical computations on the self-potential variation by the simulated groundwater
flow, and compare the result with those observed by laboratory experiments. In the result, thesimulated self-potential variation is consistent with observed one.
Then, we developed self-potential tomography to estimate the ground water condition. And we alsocharacterize the pressure from the self-potential data, and compare the result with observedpressure head that is measured by pore-pressure gauge and found that the inverted pressure head isconsistent with observed one. In addition, we apply the self-potential data observed by the flume
test. The estimated pressure head from observed self-potential data shows the consistency withobserved pressure head. And estimated pressure head also show the characteristic distribution
before the landslide occurred. These facts are highly suggestive in effectiveness of theself-potential tomography to monitor groundwater changes associated with landslide. The details
will be given in our presentation.
Keywords: Self-potential, Landslide, Tomography©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P10 -MIS03-P11

Japan Geoscience Union Meeting 2016

A Mechanism Causing Temporal Variation in b-values Prior to a Mainshock*Jeen-Hwa Wang1
1.Academia Sinica
Observations exhibit the temporal variation in b-values prior to a mainshock. The b-value starts toincrease from the normal value at time t1, reaches its peak one at time t2, then begins to decrease
from the peak one at t2, and returns to the normal one at time t3. As t>t3, the b-value varies
around the normal one or rightly decreases with time until the occurrence of the forthcoming
mainshock at time t4. The precursor time, T=t4-t1, of b-value anomalies prior to a forthcoming
mainshock is related to the magnitude, M, of the event in a form: log(T)=q+rM (T usually in days)
where q and r are two constants. In this study, the mechanism causing b-value anomalies prior to amainshock is explored. From numerical simulations based on the 1-D dynamical spring-slider mode
proposed by Burridge and Knopoff (1967), Wang (1995) found a power-law correlation between b and s,
where the parameter s is the ratio of the spring constant (K) between two sliders to that (L)between a slider and the moving plate. The power-law correlation are b~s-2/3 for the cumulative
frequency and b~s-1/2 for the discrete frequency. Since L of a source area is almost constant for along time period, b directly relates to K. Lower K results in a higher b-value. Wang (2012) found
K=rAvp2, where rA and vp are, respectively, the areal density and P-wave velocity of a fault zone.
Experimental results show that vp is strongly influenced by the water saturation in rocks. The
water saturation in the source area varies with time, thus leading to a temporal variation in vp aswell as K. This results in the temporal variation in b-values prior to a mainshock. The modeled
result is consistent with the observed one.
Keywords: b-value, precursor time, spring-slider model, stiffmess ratio, saturation of water©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P11 -MIS03-P12

Japan Geoscience Union Meeting 2016

Integrated earthquake forecast: combination of b-value monitoring and ionosphericprecursors*takaaki Kobari1, Pen Han1, Kastumi Hattori1
1.Department of Earth Sciences, Graduate School of Science, Chiba University
In recent years, there are many electromagnetic phenomenon preceding large earthquakes. Anomaly of
the total electron content (TEC) is one of the most promising anomalies for the short-term
earthquake forecast. On the other hand, it is reported that the b-value around the epicenter region
decreases prior to the large earthquake. The b-value can compute using the Gutenberg Richter law.
The lead time is around few or tens years. In this study, we investigate the effectiveness of theintegrated analyses on the b-value for the middle-term forecast and TEC analysis for the short-term
forecast. We select the Tokachi region as a test site. We will report the results of the b-valuechanges in space and time for the stress field change and GIM-TEC and/or GPS-TEC changes. In thisreport, we will focus on the two Tokachi-oki earthquakes in 2003 and 2008. They occurred on
September 11, 2003 (M8.0) and September 26, 2009 (M7.1). In addition, we will show the results forother regions, if possible.
Keywords: Earthquake, Electromagnetic, b-value, Ionosphere©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P12 -MIS03-P13

Japan Geoscience Union Meeting 2016

Development of the quasi-real-time monitoring of volcanic lava activity using MODIS*BYOUNGJIN AHN1, Katsumi Hattori2, Nicola Genzano3
1.Department of science, Faculty of Science, Chiba University, 2.Department of Earth Sciences,
Graduate School of Science, Chiba University, 3.University of Basilicata
It is possible to quasi-realtime monitoring of volcanic lava activity could be possible if we candetect the thermal anomalies related to the exposure and lava dome of magma by satellite sensors
such as MODIS. And it can be used to help for the volcano disaster prevention. In this study, wedeal with seven volcanoes in Indonesia. First, we define the infrared radiation caused by theeruption and then, we use the statistical analysis for the radiation, and remove the cloud effects.
Finally, we investigate the abnormal values against the background level of the temperature.
We introduce an evaluation function S to remove the spatial and temporal variation from thespatial difference of the brightness temperature data between the target point and reference point(5 km distance). When we compute the differences, we need to eliminate cloud effects adequately. To
achieve this, we use the brightness temperature difference between bands of MODIS (BTD). In thisstudy, we select the following combinations ; (1) Band34-Band35 (BTD(t)-μ < kσ, k=-2.0:), (2)Band31-Band27 ( BTD(t)-μ < kσ, k=-2.6), (3) Band31-Band32 (|BTD(t)-μ| < kσ, k=-3.0), and (4)Band20-Band31 (|BTD(t)-μ| < kσ, k=-3.0). Where t, k, m, and s are the season, threshold for cloud
identification, average, standard deviation for each distribution of BTD. Until the distribution
satisfy the equation, we repeat the test. Then, we move to the next test. We perform this procedure
up to test 4. Then we get the pixels without cloud. The result is evaluated using LIDAR data
onboard CALIPSO, which has the almost same orbit and constellated with AQUA. After removing thecloud effect, we compute the deviation rate d. As results for 15 years data analysis for 7
volcanoes in Indonesia, when the deviation rate exceeds in target volcanoes 6σ, there is a tendency
to have a lava volcanic activities. However, without removing the cloud effects, we find it isdifficult to identify the anomaly related to the lava activities. Therefore, it is highlysuggestive of the proposed method is valid for monitoring volcanoes and volcanic risk reduction.
Keywords: MODIS, Volcano, Remote Sensing©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P13 -MIS03-P14

Japan Geoscience Union Meeting 2016

MT survey and its preliminary result at Boso Peninsula, Japan (2)*Naoki Koizumi1, Hao Cheng1, Peng Han1, Chie Yoshino1, Katsumi Hattori1, Mao Okuda2, Kotaro Sugano2,
Midori Hayakawa2, Toru Mogi2, Shin'ya Sakanaka3
1.Graduate School of Science, Chiba University, 2.Graduate School of Science, Hokkaido University,
3.Department of Earth Science and Technology, Graduate school of Engineering and Resource Science,
Akita University
A magnetotelluric (MT) survey is one of the methods to understand the underground electric
properties. In Boso area, Japan, there are three main topic to perform the MT survey; (1) toestimate underground resistivity structures related to the plate boundaries, seamount, asperities,
and slow slip events; (2) to obtain a regional realistic resistivity structure for the numericalsimulation in generation and propagation mechanisms of electromagnetic precursors, and (3) todevelop a new MT technique to reduce the cultivated noises such as DC-driven train system andfactories. For challenges to solve them, we decided to carry out the MT survey in Boso area, Japan
during 2014-2016. Due to sensing down to 100 km depth, we used induction and fluxgate
magnetometers. We set 41 and 12 sites for induction and fluxgate type magnetometers, respectively.
The preliminary 1-D inversion results for 41 induction sites show that we can presume apparent
resistivity about 1 km - 10 km depth from the surface, but relatively not clear about 100 m - 1 km
and 10 km - 100 km depth from the surface. In addition, we found that the noises tend to be weakerin the southern region compared to the northern region.
To presume resistivity structure in Boso Peninsula, it is necessary to remove the artificial
noises from observed MT data. The observed noises have characteristics of transient signals andprocesses in time domain are required such as singular spectrum analysis. Moreover, twe will
analyze the observed data of 12 stations in which we used fluxgate type magnetometer to obtainlower frequency and deeper information.
Keywords: MT method, Boso Peninsula©2016. Japan Geoscience Union. All Right Reserved.

- MIS03-P14 -