| FAQ |
|
|
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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). |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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]
 |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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). |
|
|
▲Go to the top of this page
|
| 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". |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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] | | 0003 | 1 | 20 | FUJ | U | 3 | 10 | 234 | m/s | 1.0 | 0.7 | 54 | 9.77e-3 | 35.3103 | 138.6789 | 1040 | 0.0 | 0.0 |
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 ) )
|
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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.
 |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|
|
▲Go to the top of this page
|
| 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. |
|