SSS03-01

Japan Geoscience Union Meeting 2016

The Global Earthquake Activity Rate (GEAR) forecast test
*David D Jackson1, Peter Bird1, Yan Y Kagan1, Corne Kreemer2, Ross Stein3
1.University of California Los Angeles, 2.University of Nevada Reno, 3.Temblor.net
We present a global seismicity reference model based on uniform global datasets, transparently
merging the best features of competing approaches and resulting in a testable product. In the past,
two approaches to forecasting shallow seismicity have had comparable success. The tectonic method
is based on maps of deforming regions and/or active faults, with some empirical calibration ofseismic coupling. This captures the distribution of energy sources and may provide good forecasts
for very long time windows. The smoothed seismicity approach applies optimized smoothing tocataloged earthquakes. This captures triggering, including ongoing aftershock sequences, and may
work best on short to intermediate timescales. Here we combine a leading global forecast of eachtype using several kinds of combination: linear, log-linear, and an envelope method. We test thesuccess of each parent and hybrid forecast in an 8-year retrospective test by information score,area skill score, and spatial-likelihood metrics that are all roughly independent of total
earthquake rate. In this 2005-2012 test, the most successful hybrid model is the log-linear mixtureof 60% seismicity with 40% tectonics. This hybrid outperforms both parent forecasts. The chancethat this improvement results from a temporary random fluctuation is much less than 1%. We also
test all models against the analog-instrumental catalog years 1918-1976; the same patterns ofhybrid improvement are found. Likelihood scores are generally less than for the more recent
catalog, possibly because of limitations in the older data. We compute an update of the preferredhybrid model using all modern catalog years 1977-2013, for future prospective testing. This hybrid
model is named Global Earthquake Activity Rate model 1 (GEAR1) and is provided on a 0.1° ×0.1°
global grid, for hypocentroid depths up to 70 km, with magnitude bins whose centers range from 6.0
to 9.0 in steps of 0.10. Comparing our GEAR1 forecast to the recent fault-based UCERF3 long-term
forecast in California, we find that both predict the same total earthquake rates (within 4%) ateach of two thresholds, but that the map patterns of the GEAR1 forecast most strongly resemble themaps of UCERF3 after spatial smoothing with characteristic distances of 25~30 km has been applied
to UCERF3.
Keywords: earthquake, forecast, global, test

©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-01 -SSS03-02

Japan Geoscience Union Meeting 2016

Hybrid Models and Time-dependent Hazard in New Zealand*Matt Gerstenberger1, David Rhoades, Annemarie Christophersen, David Harte, Bill Fry
1.GNS Science
Recent work in earthquake forecasting in New Zealand has been at the interface of earthquake
forecasting (or operational earthquake forecasting) and seismic hazard analysis. One of our aims
has been to develop models that can transition for short-term forecasting to the time scales thatare required by seismic hazard analysis. As part of this we have been developing hybrid forecast
models that utilise alternative data sets to the earthquake catalogue. Recent results have shown
significant improvements in forecast skill by including by geological information and geodetic
strain rain information. Another important challenge has been to develop homogeneous catalogues
that allow for consistent forecasting from earthquake rates through to ground-motion prediction
equations. We have also been endeavoring to understand the impact of uncertainties (e.g., from thecatalogue through to model uncertainty) have on the final forecasts. Finally, we will discuss someof the challenges we are currently facing in testing of earthquake forecast models.
Keywords: earthquake forecasting, statistics, seismic hazard©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-02 -SSS03-03

Japan Geoscience Union Meeting 2016

3D spatial models for seismicity beneath Kanto region*Yosihiko Ogata1,2, Koichi Katsura1, Hiroshi Tsuruoka2, Naoshi Hirata2
1.The Institute of Statistical Mathematics, Research Organization of Information and Systems,
2.Earthquake Research Institute, University of Tokyo
Development of point-process models for the seismicity in 3D space (longitude, latitude and depth)
beneath Kanto area down to 100km depth is more required than for seismicity in the rest of theworld. This is because the three tectonic plates meet beneath Kanto plain; and interactions among
the interplate and intraplate earthquakes are too complex to make detailed analysis and forecasts
in 2D space that ignores the depths.
We consider the 3D hierarchical space-time ETAS (epidemic-type aftershock sequence) model. Amongthe characterizing parameters, the background seismicity rate \mu and aftershock productivity K
are highly sensitive to the locations, so that these parameters should be location-dependent.
Furthermore, the impact of the 2011 Tohoku-Oki earthquake of M9.0 to the seismicity beneath the
Kanto region has been so large that we need a space-time function for representing the amount of
the induced seismicity beneath Kanto by this giant earthquake. Specifically, we adopt the
Omori-Utsu function as the effect of induced earthquakes, started after the occurrence time of the
Tohoku-Oki earthquake, where we assume that the aftershock productivity parameter KM9 of the
Omori-Utsu function is also location-dependent. For forecasting future large earthquakes, we
further need to estimate the location-dependent b-value of the Gutenberg-Richter law.
The spatial variations of the characteristic parameters \mu(x,y,z), K(x,y,z) , KM9(x,y,z) and b(

x,y,z) of our model are inverted to visualize the regional changes of the seismic activity. For
this objective, we make 3D Delaunay tessellation of the Kanto volume, where every earthquake
belongs to vertices of a tetrahedron. Each of the above mentioned parameter function is a3-dimensional piecewise linear function defined by the values at the four Delaunay tetrahedral
vertices.
The estimates of the focal parameter functions are obtained by an optimal trade-off between the
goodness of fit to the earthquake data and the smoothness constraints (or roughness penalties) of
the variations of parameter values. Strengths of the constraints of or the penalties to respective
parameter functions can be simultaneously adjusted from the data by means of an empirical Bayesian
method using the Akaike’s Bayesian information criterion (ABIC).
Keywords: ABIC, aftershock productivity, background seismicity rate, b-values, Delaunay function,
Omori-Utsu function for induced seismicity©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-03 -SSS03-04

Japan Geoscience Union Meeting 2016

Optimized physics-based earthquake forecasts for inland Japan*Margarita Segkou1, Jiancang Zhuang2
1.BGS, 2.ISM
We focus on the stress recovery processes after the M=9.0 Tohoku mega-earthquake and how the above
influences the earthquake probabilities in active faults of inland Japan. Recent studies present
evidence about rapid stress recovery near the trench but as anticipated by rate-and-state friction
law, returning to pre-Tohoku “normal” seismicity levels for the active faults in inland Japan is aslower process. We perform a retrospective forecast spanning 10 years (2004-2014) in the Niigata
prefecture (mid-west Japan) using physics-based modeling, combining rate-and-state law and Coulomb
stress changes, to study earthquake-triggering mechanisms. The key element of our innovation liesin the development of 429 forecast models, as a result of a stochastic optimization withinshort-time frames (10 days), in order to access the variability of fault constitutive parameters.
The aforementioned optimized forecast then competes with a benchmark statistical/empirical
Epidemic-Type Aftershock Sequence (ETAS) model already submitted in CSEP-Japan. The testing period
starts with the M=6.8 2004 Chuetsu mainshock and ends on December 2014, approximately 9 months
after the M=6.7 post-Tohoku mid-Niigata on April 12th, 2011. Our physics-based optimization goes
hand in hand with uncertainty consideration related with the estimation of static stress changes(geometry of active faults, receiver depth, effective friction coefficient) following the M=6.8
Chuetsu mainshock and important triggered events at the near source are, the 2007 M=6.7
Chuetsu-Oki and the M=6.2 post-Tohoku event. The forecasts are evaluated for their predictability,
spatial consistency and relative information gain through log-statistics by considering thestatistical model as reference. We find that: (1) best-fit solutions correspond to stressing rates
between 0.01 and 0.8 bar/yr immediately after the aforementioned mainshocks and (2) Asigma values
vary between 0.1 and 2.0, for the few first days following the post-Tohoku and Chuetsu events.
Keywords: physics-based forecasting, stress changes, post-Tohoku recovery©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-04 -SSS03-05

Japan Geoscience Union Meeting 2016

Resolving Stress Singularities: a Retrospective Japan Rate-and-State Earthquake Forecast*Anne Elizabeth Strader1, Yosihiko Ogata3,2, Naoshi Hirata2, Hiroshi Tsuruoka2, Danijel Schorlemmer1
1.GFZ Potsdam, 2.ERI, The University of Tokyo, 3.The Institute of Statistical Mathematics
Retrospective evaluations of rate-and-state Coulomb stress transfer have shown consistent associations between increased Coulomb stress and seismicity rates. However, stress singularities
occurring at the ends of fault dislocation patches tend to provide an unrealistic calculated stressfield near active faults, where most earthquakes occur. The effects of such stress calculation
artefacts
may be mitigated through implementation of an inverse rate-and-state model, where seismicity ratevariations are inverted to obtain Coulomb stress steps over time. The resulting stress variations,from which expected seismicity rates are derived, show potential near the Tohoku rupture plane ina short-term prospective Japan forecast due to low magnitude completeness thresholds, which allow
for comprehensive delineation of the Coulomb stress field. An additional advantage of the stressinversion model is that it does not require receiver plane orientations or focal mechanisms, which
add uncertainty to the calculated stress field and are not always available, limiting thereliabilityof applying the forward model in a global earthquake forecast. We retrospectively test our forecast
within all Japan CSEP (Collaboratory for the Study of Earthquake Predictability) testing regions,just after the 2011 Tohoku earthquake. To determine whether the observed seismicity rate variations are sufficient to define Coulomb stress field variations, we combine our forecast with ETAS
forecasts currently being tested in the Japan CSEP testing center. At the 95% significance level,
the rate-and-state forecast displays potential in defining the magnitude distribution of futureearthquakes, but does not yet reliably constrain the number, or the spatial distribution of earthquakes
away from the mainshock, indicating that the inverse forecast may be most effectively applied in
an ensemble earthquake forecast model, where it contributes more to forecasted seismicity rates
near areas with recent seismicity.
Keywords: forecast, seismology, Coulomb stress©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-05 -SSS03-06

Japan Geoscience Union Meeting 2016

Impact of automatic catalog quality on real-time aftershock forecasting*Takahiro Omi1, Yosihiko Ogata2,3, Katsuhiko Shiomi4, Bogdan Enescu2,5, Kaoru Sawazaki4, Kazuyuki
Aihara1
1.Institue of Industrial Science, the University of Tokyo, 2.The Institute of Statistical
Mathematics, 3.Earthquake Research Institute, University of Tokyo, 4.National Research Institutefor Earth Science and Disaster Prevention, 5.Faculty of Life and Environmental Sciences, Universityof Tsukuba
A hypocenter catalog is the main input for earthquake forecasting. Thus the quality of the catalog
may have a considerable impact on the forecasting performance. This issue is important especiallyfor aftershock forecasting because the short-term forecast is prepared based on the hypocenter
catalog available in real-time during occurrences of aftershocks, but its quality is generally low
as compared to the final version of the edited catalog. For example, many aftershocks including
even moderate ones in the first few hours after a main shock are missing in real-time data. Here weare concerned with automatically determined hypocenters without any manual amendments, and we
examine how the raw quality of the real-time data affects the performances of aftershock
forecasting. In this study we examine the automatic hypocenter catalog of the High Sensitivity
Seismograph Network (Hi-net [1]), and conduct forecast experiments of inland aftershock sequencesin Japan. We compare forecasting performances between this Hi-net automatic catalog and the JMA
revised catalog [2]. We also consider several automatically modified versions of the Hi-net
catalog, and examine what kind of factors in the raw catalog are important for improving theforecasting performance.
[1] Okada, Y. et al. (2004), Recent progress of seismic observation networks in Japan -Hi-net,
F-net, K-NET and KiK-net-. Earth, Planets and Space 56, 15–28.
[2] T. Omi, Y. Ogata, K. Shiomi, B. Enescu, K. Sawazaki, K. Aihara, “Automatic aftershock
forecasting: A forecast test of aftershocks using the real-time data in Japan” (in preparation)
Keywords: aftershock, probabilistic forecasting, real-time data

©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-06 -SSS03-07

Japan Geoscience Union Meeting 2016

Universal slip statistics: from nanopillars to earthquakes*Dahmen A Karin1, Danijel Schorlemmer2
1.Department of Physics, University of Illinois at Urbana Champaign, 2.German Research Centre forGeosciences, Telegrafenberg, 14473 Potsdam, Germany
The deformation of many solid materials is not continuous, but discrete and jerky, with sudden,intermittent slips, similar to earthquakes. We discuss a simple model thatpredicts that thestatistical distributions of the slips should be universal, i.e. they should be the same for manydifferent materials, spanning a wide range of scales, from nanometer-sized crystalline pillars toearthquake faults that are a hundred kilometers long. We show a comparison of the model predictions
to recent experiments on many different materials,
ranging from nanocrystals, to bulk metallic glasses, to granular materials, to earthquakes and findgood agreement with the model predictions. Tools from the theory of phase transition, such as therenormalization group can be used to explain the wide applicability of the simple model. The study
provides intuition and a unified framework to understand the fundamental properties ofshear-induced deformation in systems ranging from nanocrystals to earthquakes. It also provides
many new predictions for future experiments, observations, and simulations. The results can be used
for materials testing, evaluation, and hazard prevention.
Reference:
Jonathan T. Uhl, Shivesh Pathak, Danijel Schorlemmer, Xin Liu, Ryan Swindeman, Braden A.W.
Brinkman,, Michael LeBlanc, Georgios Tsekenis, Nir Friedman, Robert Behringer, Dmitry Denisov,Peter Schall, Xiaojun Gu, Wendelin J. Wright, Todd Hufnagel, Andrew Jennings, Julia R. Greer, P.K.
Liaw, Thorsten Becker, Georg Dresen, and Karin A. Dahmen, Universal Quake Statistics: From
Compressed Nanocrystals to Earthquakes, Scientific Reports 5, 16493 (2015)
Keywords: Earthquakes, Statistics, Universality, Seismology, Experiments, Scaling©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-07 -SSS03-08

Japan Geoscience Union Meeting 2016

Evolution of earthquake rupture potential along the Pacific Plate off Japan, inferred fromseismicity
Thessa Tormann1, Stefan Wiemer1, *Bogdan Enescu2,3, Jochen Woessner4
1.ETH Zurich, Switzerland, 2.University of Tsukuba, Japan, 3.Institute of Statistical Mathematics,
Tokyo, Japan, 4.Risk Management Solutions Inc., Zurich, Switzerland
One of the major unresolved questions in Seismology is the evolution in time and space of theearthquake rupture potential and thus time-dependent hazard along active faults. What happens after
a major event: is the potential for further large events reduced as predicted from elastic rebound,or increased as proposed by current-state short-term clustering models? How does the rupture
potential distribute in space, i.e. does it reveal imprints of stress transfer?
Based on the rich earthquake record along the Pacific Plate off Japan we investigate what
information on spatial distributions and temporal changes of normalized rupture potential (NRP)
for different magnitudes can be derived from time-varying, local statistical characteristics ofwell and frequently observed small-to-moderate seismicity. The NRP is obtained from thefrequency-magnitude distribution of sampled earthquakes, specifically from the slope (b-value) andy-intercept (a-value) of this distribution, in a log-linear plot. The b-values describe therelative frequency of large versus small earthquakes, while a-values express the seismic activity
during the observation period (in this study, the a-values are annualized and distance-weighted,
i.e. we consider the relative earthquake-grid-point distances, with close-by events gaining higher
weights than more distant events). We analyze the seismicity from 1998 ~ 2015, including themassive 2011 M9 Tohoku-oki earthquake and its aftermath.
Seismicity records show strong spatio-temporal variability in both activity rates and size
distribution. We show first (Tormann et al., 2015) that the size distribution of earthquakes has
significantly changed before (increased fraction of larger magnitudes –relatively small b-values)
and after that mainshock (increased fraction of smaller magnitudes –relatively large b-values);
these changes are particularly stronger in areas of highest Tohoku-oki coseismic slip. Remarkably,a rapid recovery of this effect is observed within only few years.
We then combine this significant temporal variability in earthquake size distributions (bvalues) with local activity rates (a-values) and infer the evolution of NRP distributions. We study
complex spatial patterns and how they evolve with time, focusing on the detailed temporalcharacteristics in a simplified spatial selection, i.e. inside and outside the high slip zone of
the M9 earthquake. We resolve an immediate and strong NRP increase for large events prior to the
Tohoku-oki event in the subsequent high slip patch and a very rapid decrease inside thishigh-stress-release area, coupled with a lasting increase of NRP in the immediate surroundings.
Even in the center of the Tohoku rupture, the NRP for large magnitudes has not dropped below
long-term average values and is now not significantly different from conditions a decade before theM9 event.
Keywords: Tohoku-oki earthquake, seismic hazard, subduction zone seismicity©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-08 -SSS03-09

Japan Geoscience Union Meeting 2016

ISC Data for Earthquake Statistics*Dmitry Storchak1, Domenico Di Giacomo1, James Harris1
1.International Seismological Centre
The International Seismological Centre (ISC) is charged with production of the ISC Bulletin –thedefinitive summary of the global seismicity covering the entire period of instrumental recordings
between 1904 and 2016. It is based on the reviewed seismic bulletin reports from over 130 seismic
networks worldwide and includes a total of 5.8 million seismic events with 1.9 millions of them
reviewed by the ISC analysts. The main purpose of this huge dataset is to include as many seismic
events around the globe as possible to provide the most complete and comprehensive list ofearthquakes and other seismic events in a homogeneous way. In fact, there are considerable temporaland region-to-region variations in the magnitude completeness and hypocentre location accuracy ofreports from local and regional seismic networks and observatories. These variations are dictatedby the distribution and quality of local seismic networks, waveform processing procedures as wellas administrative and political decisions that control reporting bulletin data to the ISC. The
content of local bulletin reports have also changed dramatically through the period of instrumental
recordings thus affecting the content of the ISC Bulletin as a whole. Statistical studies ofseismicity patterns, b-value, earthquake rate are also subject to an accurate identification ofanthropogenic events or events caused by anthropogenic activities. These studies often require theremoval of aftershocks series. This presentation lays out major principles of building the ISC
Bulletin, describes the complexity of event information, and provides recommendations for practicaluse of the enclosed information.
In addition to the Bulletin as its flagship product, the ISC is maintaining a set of specialized
products that both narrow down and extend the information from the ISC Bulletin to serve thepurpose of specific groups of geoscientists. Thus we prepared and continue extending the ISC-GEM
Global Instrumental Earthquake Catalogue widely used for estimation of global and regional
earthquake hazard. The ISC-EHB dataset is maintained for users interested in less complete list of
events with considerably higher accuracy of event epicenter and depth determination. It is used in
global and regional studies of tectonics, surface geology and inner structure of the Earth. Other
datasets include the GT bulletin, CTBTO Link, Event Bibliography and Seismological Contacts.
Keywords: earthquake, global, bulletin©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-09 -SSS03-10

Japan Geoscience Union Meeting 2016

Underestimate of the size of microearthquakes by the JMA magnitude scale and its infuence
to earthquake statistics*Takahiko Uchide1, Kazutoshi Imanishi1
1.Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, National
Institute of Advanced Industrial Science and Technology (AIST)
Earthquake statistics needs parameterized information on earthquakes. One of such parameters is themagnitude. The local magnitude scales, such as the JMA magnitude (Mj), based on amplitudes ofseismograms are easy to estimate and therefore usually included in earthquake catalogs. The moment
magnitude (Mw) is based on the physical source parameter, seismic moment, however needs much effort
for the estimation especially for microearthquakes. Though the consistency between Mj and Mw isguaranteed for the medium earthquakes, we need to check that for microearthquakes.
As for use of earthquake catalogs, we should know the completeness magnitude above which catalog iscomplete. A type of it is Mc defined as a magnitude where magnitude-frequency distribution starts
deviating from the Gutenberg-Richter’s (GR) law. Another one is based on earthquake detectability.
Schorlemmer and Woessner [2008] proposed MP based on the detectability inferred from the pickinformation. They showed the Californian case that MP is smaller than Mc, which indicates thebreakdown of the GR law. It is important to confirm if the breakdown really occurs. Our study
investigates if the discrepancies are also seen in case of Mw.
Mw Estimation for Microearthquakes
We stably estimate seismic moment of microearthquakes based on moment ratios to nearby small
earthquakes whose seismic moments are available in the NIED MT catalog, by a multiple spectral
ratio analysis [Uchide and Imanishi, under review]. Applying this method to earthquakes inFukushima Hamadori and northern Ibaraki prefecture areas, eventually we obtained the seismic
moments of a total of 19140 earthquakes (Mj 0.4 - 3.8). The striking result of this study is thatthe change in slopes of the Mj-Mw curve: 1 and 0.5 at higher and lower magnitudes, respectively(see Figure). The discrepancies between Mj and Mw are significant for microearthquakes, suggestingthat Mj underestimates the sizes of microearthquakes.
Completeness Magnitudes and b-values
The result above must affect earthquake statistics. Here we study Mc and b-value of the GR law.
Following Ogata and Katsura [1993], we assume the earthquake detectability as the cumulative normal
distribution with a mean, μ, and a standard deviation, σ, and estimate the GR parameters (a and b)
together with μand σ. We define Mc = μ+ 2.33 σwhere the detection rate is 99 %. Applying thismethod to the monthly seismicity data in the study area, we found that the Mc for Mw is lower thanthat for Mj converted into Mw, however still larger than MP converted into Mw. This may be due tothe breakdown of the GR law for microearthquakes, though another possibility is that theincompleteness of earthquake catalog overestimates the detectability, resulting the underestimateof MP.
b-values for Mw (bw) are systematically larger than those for Mj (bj). The temporal trends for bw
and bj are similar to each other. When bj increases, bw also increases. This does not affectdiscussions inferred from the qualitative temporal change in b-values [e.g., Nanjo et al., 2012]. bw

is often larger than 1.5, indicating that the moment release is dominantly done by smaller

earthquakes.
Acknowledgement
We used the JMA Unified Earthquake Catalog, seismograms from NIED Hi-net and the NIED moment tensor
catalog.

©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-10 -SSS03-10

Japan Geoscience Union Meeting 2016

Figure: Comparison between Mj and Mw inferred from the multiple spectral ratio analyses (color
image for the distribution and circles for the median Mw) and the NIED MT solutions.
Keywords: Earthquake statistics, JMA magnitude, Moment magnitude, Spectral analysis, Completenessmagnitude, b-value©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-10 -SSS03-11

Japan Geoscience Union Meeting 2016

Assessment and optimization of the potential earthquake precursory information in ULF
magnetic data registered at Kanto, Japan during 2000 –2010*Peng Han1,2, Katsumi Hattori1, Jiancang Zhuang2
1.Graduate School of Science, Chiba University, Chiba, Japan, 2.Institute of Statistical
Mathematics, Tokyo, Japan
In order to clarify the ULF seismo-magnetic phenomena, a sensitive geomagnetic network has been
installed at Kanto, Japan since 2000. In previous study, we have verified the correlation between
ULF magnetic anomalies and local sizeable earthquakes by both case and statistical studies. In thispaper, we use the Molchan’s error diagram to evaluate the potential earthquake precursory
information in the magnetic data registered at Kanto, Japan during 2000 –2010. The results showthat the earthquake predictions based on magnetic anomalies are clearly better than those based on
random guess, which indicates the magnetic data contain potential useful prediction information.
Further investigations suggest that the prediction efficiency depends on the distance (R) and thesize of the target earthquake events (Es). Finally, we introduce the probability gain (PG') andthe probability difference (D') to explore the optimal prediction parameters for a given ULF
magnetic station. For Seikoshi (SKS) station in Izu, optimal R and Es are about 100 km and 108.75,
respectively; and for Kiyosumi (KYS) station in Boso, they are about 180 km and 108.75,
respectively.
Keywords: earthquake precursory information, Molchan’s error diagram, statistical analysis,
parameter optimization , ULF magnetic data

©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-11 -SSS03-12

Japan Geoscience Union Meeting 2016

Prospective validation of physical-based precursors and their potential for short–term
earthquake forecasting. Case study for Japan 2014-2016*Dimitar Ouzounov1, Katsumi Hattori2
1.Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of
Science & Technology Chapman University, Orange, California, USA, 2.Department of Earth Sciences,
Chiba University, Chiba, JapanWe are presenting a prospective validation of short-term pre-earthquake phenomena preceding major
earthquakes. Our challenge question is: “Whether such physical-based signals are significant andcould be used for early warning of large earthquakes?” To address this question we have started
continuous validation of atmospheric signals in retrospective/ prospective modes over Japan. Our
approach is based on multidisciplinary analysis of several physical and environmental parameters(Satellite transient infrared radiation (STIR), electron concentration in the ionosphere (GPS/TEC),
radon/ion activities, air temperature and seismicity patterns) that were found to be associatedwith earthquakes. The science rationale for multidisciplinary analysis is based on concept
Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) (Pulinets and Ouzounov, 2011]), which explains
the synergy of different processes and anomalous variations, usually named short-term
pre-earthquake anomalies.
Our validation processes consist in two steps: (1) A continuous retrospective analysis preformed
over two different regions with high seismicity- Taiwan and Japan for 2003-2011 (2) Prospective
testing with potential for M6.5+ events Japan for 2014-2015 period. The test results suggest
appearance of physical pre-earthquakes anomalies, one to several days in advance to major events,
including the largest earthquakes - M7.8 of 30 May 2015 and all other M6.5+ for that period. The
false alarm ratio for the testing period has shown false positives less then 20%. Our initialprospective tests show that multi-parameter analysis could reveal short-term pre-earthquake
anomalies prior to the largest earthquakes in Japan.
Keywords: earthquake precursor, forecasting, early warning system©2016. Japan Geoscience Union. All Right Reserved.

- SSS03-12 -