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FAQ

INDEX    * Go to the answer of the question when you click the link.

Question18. Sometime there are differences between the content of various automatic processing products of Hi-net, like epicentral maps and earthquake hypocentral lists. Why is that?
Question17. I felt ground shaking, but a continuous waveform image did not show any change.
Question16. On the maximum amplitude distribution maps on the page of the AQUA system, there are a lot of "black circles".
How and where is strong ground motion observed in these figures?
Question15. My colleagues already have the Hi-net data. Can I use this data for my research?
Question14. How do you determine the region name shown in earthquake information?
Question13. I checked the Hi-net website just after I felt ground shaking, but I could not see earthquake information on it.
Question12. What are two pulses regularly appeared at 9:00:00 am and 9:00:05 am (JST) everyday?
Question11. Continuous waveform images sometimes become black or white completely. What does it mean?
Question10. Can I use "win32tools" on my "Windows" PC?
Question09. What is the "WIN32" format?
Question08. How can I convert the A/D value from an WIN32 file to the corresponding physical quantity?
Question07. Can I post the data and/or graphical images download from the NIED Hi-net website on my web page?
Question06. I saw a website using Hi-net data. Can we redistribute your data?
Question05. Could I make a hypertext link of the NIED Hi-net website on my website?
Question04. Sometimes continuous waveform images do not draw seismograms. What is happening?
Question03. Can I get the old NIED Hi-net hypocenter catalog before the JMA unified hypocenter catalog that started in October, 1997?
Question02. Can I access the JMA unified hypocenter catalog before June 3, 2002?
Question01. I want the waveforms recorded the 1995 Hyogo-ken Nanbu earthquake (the Kobe earthquake). How do I get them?

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Q18 Sometime there are differences between the content of various automatic processing products of Hi-net, like epicentral maps and earthquake hypocentral lists. Why is that?
A18 In some cases there might be differences between various hypocentral information sources.

Hypocentral information is revised any time since the inability to locate an earthquake due to insufficient information or the large uncertainties associated with the location of a certain event requires additional data processing in some cases. While the updating process takes place continuously and the most recent information becomes available, the update time for the various Hi-net products may differ slightly and thus there might be differences in the displayed content.
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Q17 I felt ground shaking, but a continuous waveform image did not show any change.
A17 We may repair observation equipment (seismographs, data recorder etc.).

We, NIED, try to repair broken seismographs and/or recorders as quickly as we can to maintain stable observations. Before we repair broken observation equipment, waveform data at that station is incorrect.
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Q16 On the maximum amplitude distribution maps on the page of the AQUA system, there are a lot of "black circles".
How and where is strong ground motion observed in these figures?
A16 To draw the maximum amplitudes on the AQUA pages, we use the NIED Hi-net waveform data. Since the main target of the Hi-net seismometers are mainly very small ground motions, it is difficult to observe strong ground motions precisely.

NIED Hi-net is constructed for observation of small seismic ground motions using high-sensitivity sensors. Therefore, it is hard to observe strong ground motions precisely.
We recommend you to use waveform data observed by strong motion seismograph networks (K-NET / KiK-net).
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Q15 My colleagues already have the Hi-net data. Can I use this data for my research?
A15 We prohibit re-distribution of all data from our website.

In order to evaluate the efficacy of our seismograph networks and to continue our web service, NIED has accumulated records of our seismic data. These records are very important for maintenance and improvement of our system. Do not redistribute data you downloaded from our website. If redistribution becomes common, we will not be able to catch the above information. It means we cannot explain how important our service is and we will have no choice but to close our website. If you want to use our data, you have to apply for our data providing service. It is not necessary to inform us if your case fulfills the following both cases: 1) You share the Hi-net data with your colleague(s) who have already applied for using data, AND 2) the subject of your study has already been shared with us. Even if this is case, send us your products obtained using the data provided from our website.
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Q14 How do you determine the region name shown in earthquake information?
A14 The region name is referred to "The Seismological Bulletin of Japan" issued by the JMA.

In "The Seismological Bulletin of Japan", the JMA divides the Japan region into many regions according to local earthquake activity. Region names are defined from an epicenter location automatically. One of the main aims of the NIED Hi-net is to understand local earthquake activity, we obey the epicenter name determined by "The Seismological Bulletin of Japan". Region size seems to correspond to seismic activity, thus you may feel some region names are strange. When the JMA defines an individual name for an earthquake with large damage, we use it on our website.

[Details will be displayed when you click on the map]

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Q13 I checked the Hi-net website just after I felt ground shaking, but I could not see earthquake information on it.
A13 Our preliminary earthquake information is a result of the automatic hypocenter determination system. We do not show results with large estimation error.

We automatically analyze the NIED Hi-net waveform data 24 hours, 365 days and detect hypocenter locations and their magnitudes. When large earthquakes occur we show our results on the NIED Hi-net website as a preliminary result. As this procedure is completely automatic, the results might be not very precise. Sometimes our system cannot estimate hypocenter information, and sometimes our automatic results have large estimation errors. We do not show these information on the Hi-net website. Check information provided by the JMA.
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Q12 What are two pulses regularly appeared at 9:00:00 am and 9:00:05 am (JST) everyday?
A12 They are test signals to check the state-of-health of the observation instrument.

These pulses are used to confirm that the seismometer is working properly. For Hi-net stations, these pulses are inserted at 9:00:00 am and 9:00:05 am (JST).
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Q11 Continuous waveform images sometimes become black or white completely. What does it mean?
A11 This is not caused by any underground phenomena.

For drawing continuous waveform images, we set amplitude-level of the waveform to check waveforms by local micro-earthquakes. However, images sometimes become "black" at the stations located in urban area or coast area because of the poor signal-to-noise ratio. Even at low-noise station, "black image" may appear when some construction work starts near stations or when seismograph has some trouble. Alternatively, when waveform data transfer is not successful and data is not delivered to the NIED DMC, continuous waveform image become "white".
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Q10 Can I use "win32tools" on my "Windows" PC?
A10 Some tools are available on the following URL.

As we described in No.09"win32tools" is designed to run on UNIX/Linux platforms. However, some commands such as "dewin_32", "wch_32", and "wck_32" have been modified for MS-Windows command prompt, and they are available from here. Now we are testing them on Windows 7 SP1, 8 and 8.1. For more details on these commands, see No.09, No.08 and the website of Earthquake Research Institute, the University of Tokyo.
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Q09 What is the "WIN32" format?
A09 NIED extended the Japanese popular seismic waveform data format "WIN" developed by the University of Tokyo. We named this extended format as "WIN32".

Click here for the website of the WIN system. Some commands provided in the WIN system have been modified for WIN32 by NIED and distributed from this page. These tools run on UNIX/Linux platform. To download these tools, you are required to complete the user registration. Using these tools, you can extract the A/D value for a given channel in text format from a WIN32 file. Try this command (% is a prompt sign):

% dewin_32 -c [hexadecimal channel number] [input file name (WIN32 format)] > [output file name (text format)]


* For the method to convert the A/D value to the corresponding physical quantity, see No.08.
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Q08 How can I convert the A/D value from an WIN32 file to the corresponding physical quantity?
A08 You should use a channels table file included in the downloaded file.

The following is an example channels table file (this example has been taken from the manualpage of the WIN system provided by ERI, the University of Tokyo):

#[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]
0003120FUJU310234m/s1.00.7549.77e-335.3103138.678910400.00.0

where each column contains the following information:

[1] Hexadecimal channel number (2-byte).
[2] Record flag.
[3] Line delay (ms).
[4] Station code.
[5] Component code.
[6] Reduction ratio of monitoring waveform (expressed as the integer exponent of a power of 2).
[7] Quantization bit rate in A/D conversion.
[8] Sensor sensitivity (V/unit of input, where unit of input is provided in column [9]).
  This value can be either an integer or a real number.
[9] Unit of input. Use MKS system: "m" for displacement, "m/s" for velocity, and "m/s/s" for acceleration.
[10] Natural period of the seismometer (s).
[11] Damping constant of the seismometer.
[12] Amplification factor applied to sensor output prior to A/D conversion (dB).
[13] Quantization width in A/D conversion (V).
[14] Station latitude (degrees). A positive value indicates North latitude.
[15] Station longitude (degrees). A positive value indicates East longitude.
[16] Station height (m).
[17] P-wave station correction (s).
[18] S-wave station correction (s).

Using columns [8], [12], and [13], you can convert the A/D value (I) to the correspondingphysical quantity (v) as a following equation:
v = I * [13] / ( [8] * 10 ^ ( [12] / 20 ) )


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Q07 Can I post the data and/or graphical images download from the NIED Hi-net website on my web page?
A07 We prohibit any redistribution of materials on the NIED Hi-net website.

You are prohibited from redistributing the data and/or graphical images provided by the NIED Hi-net website in any form. When announcing your original results obtained by using the downloaded data, this rule does not applied. In that case, however, you are obliged to indicate that the use of the NIED Hi-net (or F-net) data. For the data provided by other organizations such as the Japan Meteorological Agency or universities, you are required to use them only in accordance with each organization's rule.
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Q06 I saw a website using Hi-net data. Can we redistribute your data?
A06 It is likely to correspond to the redistribution that we are prohibiting.

NIED retains copyrights of all the materials on this web site except when the copyright owner is indicated. This means that you may not open and redistribute any data provided on our website. However, you are able to use the original results or graphic images which are processed waveforms and/or earthquake catalog by yourself if you refer to use original dataset. We, NIED and its staff, have no responsibility whatsoever for any direct or indirect damage or loss caused by the usage of the materials provided by our website.
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Q05 Could I make a hypertext link of the NIED Hi-net website on my website?
A05 Yes, you are able to create a hypertext link of the NIED Hi-net website.

We would like you to choose URL "http://www.hinet.bosai.go.jp/", because we sometimes change the URLs of our content.

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Q04 Sometimes continuous waveform images do not draw seismograms. What is happening?
A04 Waveform data are sometimes lost because of observation system troubles and/or maintenance.

The operation of such a high-dense seismograph network is a novel challenge. Thus, we sometimes face observation system troubles and we need several tests and maintenance to achieve stable observation. At that time, waveform data are sometimes lost and the continuous waveform images may not be available.
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Q03 Can I get the old NIED Hi-net hypocenter catalog before the JMA unified hypocenter catalog that started in October, 1997?
A03 No. NIED Hi-net was established in October, 2000. JMA distribute the old JMA hypocenter catalogs on their website.

JMA started to construct hypocenter catalog around the Japan Islands using seismic stations operated by JMA, universities, NIED and other organizations in October, 1997. Before September, 1997, JMA made hypocenter catalog using only their seismograph network. All JMA hypocenter catalogs are provided by the JMA website.
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Q02 Can I access the JMA unified hypocenter catalog before June 3, 2002?
A02 We do not distribute the old JMA unified hypocenter catalogs, but JMA does.

On the NIED Hi-net website, we use the preliminary result of the JMA unified hypocenter catalog as a reference of waveform data download. That is why we made the JMA unified hypocenter catalog available after June 3rd, 2002 to the public on our website. As we wrote in the page of "How to use the Hi-net data", the hypocenter information on our website are preliminary results and this information may be revised. When you use the hypocenter information for you research, studies and work, you should get the final version of the JMA unified hypocenter catalog from the JMA website.
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Q01 I want the waveforms recorded the 1995 Hyogo-ken Nanbu earthquake (the Kobe earthquake). How do I get them?
A01 NIED Hi-net was established after the 1995 Hyogo-ken Nanbu earthquake. We have no waveform data before the earthquake.

Because the NIED Hi-net project was started after the occurrence of the 1995 Hyogo-ken Nanbu earthquake, NIED does not retain the Hi-net waveform data before that time. If you need to obtain old waveform data, you should contact to the JMA and/or the JMBSC. The data of JMA is provided by JMBSC.


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We, NIED, do not deliver any e-mails of immediate seismic information obtained by the AQUA system.
In addition, please understand that we prohibit the redistribution of the seismic data. For more information, please read How to use the Hi-net data and FAQ.
High Sensitivity Seismograph Network Laboratory, Network Center for Earthquake, Tsunami and Volcano,
National Research Institute for Earth Science and Disaster Resilience.
3-1 Tennodai, Tsukuba City, Ibaraki Prefecture, 305-0006, JAPAN
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