SSS24-P01

Room:Convention Hall

Time:May 27 18:15-19:30

Application to display Earthquake Information using Mobile Terminal
FURUDATE, Tomomichi1∗1Japan Meteorological Agency, Meteorological Research Institute

Recently, the users utilize emergency earthquake information using mobile terminals. The mobile terminals run on multiple
OS as Android or iOS etc. and have been developed using multiple programming language as C++, Java or Objective-C etc. It isdifficult to execute these programs on multiple platforms. But it is easy to execute these program on web browser with standard
as HTML5.
In this survey, I evaluate processing performance and compatibility of HTML5 programs
and make applications to display earthquake information. I tested smart phones, tablets, laptop PCs. First I evaluated performance and compatibility using programs for numerical calculation, 2D display, 3D display. The results show that programs using
HTML5 have compatibility for terminals with Windows, Android, iOS. The performances of latest mobile terminals are about
1/2 to 1/3 compared with PC. Next, I made applications to display earthquake information and evaluate the compatibility. The
programs are for information display on local map and global map, real-time seismic wave data display, semblance processingdisplay. The programs have compatibility for multiple mobile terminals.
I conclude that the programs using standard HTML5 have compatibility for multiple mobile terminals with Windows, Android,
iOS. The performances have been catch up to PC.
I plan to more survey and revamp the applications.
Keywords: mobile terminal, earthquake information, HTML5, WebGL

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SSS24-P02

Room:Convention Hall

Time:May 27 18:15-19:30

Array observation of strong motion for the precise estimation of current wavefield
OGISO, Masashi1∗ ; HAYASHIMOTO, Naoki1 ; HOSHIBA, Mitsuyuki1
1

Meteorological Research Institute

We conduct a research for the next generation of earthquake early warning based on the concept of Hoshiba (2013), where wewill predict ground motion without estimating hypocentral information. Recently, Hoshiba and Aoki (2015) presented examplesof ground motion prediction with observed records based on this concept.
For estimating current wavefield, Hoshiba and Aoki (2015) uses only amplitude at each station. It is expected that some more
information about current wavefield such as propagation direction and apparent velocity leads to more accurate estimation ofcurrent wavefield. Array observation is one of the powerful tools to observe propagation direction and apparent velocity, so that
we started array observation at the premises of our institute.
Our array network are consisted by six CV-374 type strong motion seismometers. Sampling frequency is 500 Hz. Except onestation buried under the ground, five stations are fastened to the floor of each building. The size of array network is about 300 m.
We applied semblance analysis (Neidell and Tarner, 1971) to the records of the earthquake at Northern Nagano Pref. (2014/11/22,M6.7) using 1 s time window in several frequency ranges. At the time ranges of direct P wave arrival and P coda waves, semblance value of UD component is high even in a high frequency range. Backazimuth, however, is slightly southward than theexpected arrival direction. Apparent velocity is also higher than the expected velocity, which means that the low velocity layer
under the array may affect the backazimuth and apparent velocity. At the time range of direct S wave arrival, semblance value isrelatively high for frequency under 4 Hz of horizontal component, although the backazimuth and apparent velocity at that time
is not stable compared with those of direct P waves. Backazimuth and apparent velocity becomes unstable at the time range of S
coda waves in spite of high semblance value.
To estimate the velocity structure under the array, we conducted seismic interferometry (e.g. Nagaoka et al., 2012) using
continuous records. Dispersion relation of phase velocity of Rayleigh waves from 400 to 300 m/s for 1 to 4.5 Hz, which means
the existence of low velocity layer under the array. We will further estimate the velocity structure under the array with otherinformation.
Rapid calculation is needed in semblance analysis for the purpose of earthquake early warning. We will work on the development of effective calculation considering the velocity structure, as well as the parallel computation.
Keywords: Array observation, Earthquake early warning, efficient calculation

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SSS24-P03

Room:Convention HallTime:May 27 18:15-19:30

Fast Estimate of Rupture Process of Large Earthquakes via Real Time Hi-net Data
WANG, Dun1∗ ; KAWAKATSU, Hitoshi1 ; MORI, James2
1Earthquake Research Institute, The University of Tokyo, 2 Disaster Prevention Research Institute, Kyoto University

We developed a real time/automated system based on Hi-net seismic array that can offer fast and reliable source information,for example, source extent and rupture velocity, for earthquakes that occur at distance of roughly 30- 85 degrees with respect tothe array center (Figure 1).?
We perform continuous grid search on a Hi-net real time data stream to identify possible source locations (following?Nishida,Kawakatsu, and Obara, 2008, JGR). Earthquakes that occurred off the bright area of the array (30- 85 degrees with respect to thearray center) will be ignored. Similarity of the waveforms, and location variations of the local maxima from neighboring windows
are used to verify the occurrence of large earthquakes. Once a large seismic event is identified successfully, back-projection will
be implemented to trace the source propagation and energy radiation using pre-calculated station corrections derived from nearby
earthquakes that occurred previously. An inversion will be then applied to get the detailed high frequency energy distribution.
The time required is mainly due to the travel time from the epicenter to the array stations, so we can get the results between 6
to 13 min depending on the epicentral distances. This system can offer fast and robust estimates of source information for large
earthquakes, which may be useful for disaster mitigation, such as tsunami evacuation, emergency rescue, and aftershock hazardevaluation.
Figure caption
Figure 1 Framework of the Real Time Back-Projection
Keywords: real time seismology, rupture process, Hi-net, disaster mitigation

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SSS24-P04

Room:Convention Hall

Time:May 27 18:15-19:30

REGARD - Real-time GEONET Analysis System for Rapid Deformation Monitoring SATO, Yudai1∗ ; MIYAGAWA, Kohei1 ; KAWAMOTO, Satoshi1 ; OSHIMA, Kennichi1 ; MURAMATSU, Hiroki1 ;INUKAI, Takaaki1 ; OHTA, Yusaku2 ; DEMACHI, Tomotsugu2 ; MIURA, Satoshi2 ; HINO, Ryota2 ;NAKAMURA, Yasuhiro3 ; NISHIYAMA, Mai3 ; DOUKE, Yuki3
1GSI of Japan, 2 Graduate School of Science, Tohoku University, 3 Hitachi Zosen Corporation

Geospatial Information Authority of Japan (GSI) has been operating a continuous GNSS observation network system since
1994. This system is known as GEONET (GNSS Earth Observation Network) and consists of approximately 1300 nationwide
GNSS stations (GEONET station) and the analysis center. Most stations collect GNSS data with 1-Hz sampling and transfer
them to the analysis center in real time. Those data are available for surveying or research using real-time kinematic positioning
technique. This technique is expected for describing cataclysmic earthquake from crustal displacement in short time especiallyafter the 2011 off the Pacific Coast of Tohoku Earthquake in March 2011.
GSI and Tohoku University have developed the Real-time GEONET Analysis System for Rapid Deformation Monitoring(REGARD) since September 2011 to estimate moment magnitudes (Mw) soon after large earthquakes struck. This system
consists of three subsystems. First subsystem does real-time kinematic positioning using RTKLIB (Takasu, 2011) and GSILIB(GSI, 2015). Second one detects seismogenic behavior using the RAPiD algorithm (Ohta et al. 2012) or the Earthquake EarlyWarning (Kamigaichi et al. 2009) and immediately run the third subsystem. This subsystem estimates Mw within three minutes
using displacement vectors of GEONET stations (Kawamoto, 2014). Finally, results are mailed to persons involved.
We tested this system in 2012, using 143 GEONET stations located in the Tohoku region. Last year, we expanded its function
by using all the stations receiving 1-Hz streaming data covering almost all lands of Japan and enhanced its redundancy bycarrying out two independent processing in parallel. In this year, we enhance real-time kinematic positioning by using QZSS andGLONASS as well as GPS. We also improve the browser used in the agency to search for previous results and visually recognize
results of the real-time kinematic positioning.
In this presentation, we report the brief overview and the current situation of REGARD, including the accuracy enhancement
and the browsing software.

Keywords: GEONET, RTK-GNSS, real-time

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SSS24-P05

Room:Convention Hall

Time:May 27 18:15-19:30

Real-time Damage Estimation for the 2014 Nagano Kamishiro Fault Earthquake by JRISQ
NAKAMURA, Hiromitsu1∗ ; KUNUGI, Takashi1 ; SUZUKI, Wataru1 ; AOI, Shin1 ; FUJIWARA, Hiroyuki11NIEDIt is extremely important to quickly assess the damage immediately after an earthquake for providing suitable disaster response.
We has constructed prototype of a Real-time Information System for earthQuake (J-RISQ) for appropriate decision-making
regarding the initial response at an earlier stage immediately after an earthquake by combining amplification characteristic data
for subsurface ground as well as basic data such as population and building information accumulated in J-SHIS development andobservation data including real-time strong-motion data observed by K-NET and KiK-net (Aoi et al. , 2013, Nakamura et al. ,2013). A part of J-RISQ information (including the estimated distribution of seismic intensity and the population exposed to eachseismic intensity level) is published as a ”J-RISQ Report” on http://www.j-risq.bosai.go.jp/ immediately after the occurrence ofan earthquake. In this study, we describe the estimations by J-RISQ for the 2014 Nagano Kamishiro Fault Earthquake.
J-RISQ issued five reports for this event. The first report was issued by using information from 12 observations approximately27 seconds after the earthquake. J-RISQ estimated the population exposed to the seismic intensity of 5 lower or greater to be20,000, one buildings were completely destroyed and 10 buildings partly destroyed. Eventually, the fifth report was made byusing the information from 1567 observations approximately 11 minutes after the earthquake. J-RISQ estimated the population
exposed to a seismic intensity of 5 lower or greater to be 200,000, the population exposed to a seismic intensity of 6 lower orgreater to be 20,000, 46 buildings were completely destroyed and 186 buildings partly destroyed.

Keywords: J-RISQ, real-time, Damage Estimation, 2014 Nagano Kamishiro Fault Earthquake, K-NET, KiK-net

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SSS24-P06

Room:Convention HallTime:May 27 18:15-19:30

A numerical study of real-time source mechanism inversion (GRiD-MT) considering 3D
heterogeneous subsurface structure
NAGAO, Arisa1∗ ; FURUMURA, Takashi2 ; TSURUOKA, Hiroshi3
1

III, The Univ. of Tokyo, 2 CIDIR, The Univ. of Tokyo, 3 ERI, The Univ. of TokyoAbstract
One of the main objectives in this study is upgrading the GRiD-MT system (Tsuruoka et al., 2009), which performs a moment
tensor inversion in real time basis by using both observed waveforms and correlation coefficients of Green’s function. To achieve
the goal, we firstly simulated seismic wave propagation using the finite difference method (FDM) which takes into account theheterogeneous underground structure, frequency dependence and so on.
GRiD-MT, considering 3D horizontally stratified structure model, is good for rather long period seismic waves (20-50s) and
can determine MT solutions of Mw4 class earthquakes. We would like to apply GRiD-MT much smaller magnitude and moreaccurate determination for MT solution, we have to take into account using more shorter period seismic waves (less than 20s).
We initially investigated effects of number of observation stations and frequency ranges for MT inversion. We used 2D model
to know the features of MT inversion under the heterogeneous structure. Because, in the future, we would like to use Green’sfunction under 3D heterogeneous structure model for the calculation.
We performed 2D simulation of seismic wave propagation and estimated hypocenter locations using the FDM method. We
beforehand set 96 virtual sources in the model and computed 96 Green’s functions for each observation point at the surface. So,
we determine real hypocenter by comparing actual waveforms and Green’s functions and using cross correlation coefficients.
We adopt the highest point of cross correlation coefficient as a real hypocenter. In this study, we used maximum 5 stations tocompare them.
In the future, we would like to compute 3D Green’s function for 3D heterogeneous subsurface structure. Furthermore, we havea plan to use reciprocal theorem in the GRiD-MT.

Keywords: GRiD-MT, hypocenter location, correlation coefficient

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