Introduction
Overview of K-NET
Kyoshin Net (K-NET) is a system which sends strong-motion data on the Internet, data which are obtained from 1,000 observatories deployed all over Japan. The average station to station distance is about 25km. Each station has a digital strong-motion seismograph with a wide frequency-band and wide dynamic range, having a maximum measurable acceleration of 2000 Gals. The records obtained from these seismographs are acquired at a control center in Tsukuba by telemetry. At each site the soil conditions, including P and S-waves velocity structures, have been obtained by downhole measurement. The seismographs are installed in the free field in order to have a systematic uniform recording condition. The control center makes three kinds of data files (UNIX, DOS, and ASCII) with a common header including the source parameters determined by the Japan Meteorological Agency (JMA) for each event. The control center sends one of the three files on the Internet according to the user's request. Also, the control center maintains a database of strong-motion records and site information which the user can access for scientific studies and engineering applications.
Each seismographs has two RS-232C communication ports. One is directly connected to a modem belong to a local municipal government. The offices of the municipality are able to utilize the strong-motion information for disaster assessment and management. The other communication port is connected to the control center. After receiving the prompt source information determined by JMA, the control center starts to acquire the strong-motion records by using this port. The control center compiles these strong-motion records and then makes the compiled data set available on the Internet. The distribution map of maximum acceleration is made on the basis of the data set and is also made available on the Internet.
You can connect to the home page of the National Research Institute for Earth Science and Disaster Prevention (NIED) by pointing to the address, http://www.bosai.go.jp/. Please select the home page of the K-NET from the NIED home page. Also, you can directly connect to the home page of the K-NET by pointing to the address, http://www.k-net.bosai.go.jp/. It is possible to search the strong-motion data files by selecting a site or an origin time. Site condition information is also available. There is no restriction on using the K-NET information. If you use all or part of the information including strong-motion data on the Internet, you are requested to acknowledge the data source and to send a copy of your publication to the following address:
Strong Motion Seismograph Network Laboratory, Earthquake and Volcano Data Center,
National Research Institute for Earth Science and Disaster Prevention
3-1, Tennodai, Tsukuba, Ibaraki 305-0006, Japan
Observatory
Seismograph
Applications of K-NET
Site Loacation List
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