HR: 1330h
AN: S42B-0160    [PDF]
TI: Today and Tomorrow of the Real-time Earthquake Information Equipment
AU: * Nakamura, Y
EM: yutaka@sdr.co.jp
AF: System and Data Research, 3-25-3, Fujimidai, Kunitachi-City, Tokyo, JAPAN, TOKYO, 186-0003 Japan
AB: UrEDAS, Urgent Earthquake Detection and Alarm System, can realize the real-time early earthquake detection and alarm system in the world. Although this system is actually working for mostly railroad relations, such as the Shinkansen and subway lines, it is not the system limited to the railroad field. For example, there is a local government that has realized a tsunami warning system using real-time estimated earthquake parameters as magnitude and location, distributed by UrEDAS. UrEDAS is characterized by the serial processing without storage of seismic waveform for processing. For this reason, the procedure of data processing hardly changes with usual operation also in case of an earthquake, so the system does not carry out a system failure in case of an earthquake. And also UrEDAS does not require a network and is an autonomous distributed system strong against a natural disaster or cyber-terrorism. On 26 May 2003, the Sanriku-Minami earthquake of Mj 7.0 was occurred. It was so large that the maximum acceleration of about 600 Gal was observed along the Shinkansen line and 22 columns of the rigid frame viaducts (RC) were severely cracked. This earthquake occurred on the business hours of the Shinkansen. As expected, coastline _gCompact UrEDAS_h took out the early P wave alarm before the destructive earthquake motion and the validity of this system was proved for the first time. UrEDAS on the place where many faults exist has a problem in accuracy, especially for the epicentral azimuth. UrEDAS has been observing to consider on the situations of operation under such an unfavorable condition and tried to shorten the calculation time and improve the accuracy. On the other hand, UrEDAS has examined to distribute the earthquake information via Internet. At the time of Colima, Mexico earthquake on January 2003, UrEDAS in Mexico City detected this earthquake over one minute before the large motion and sent an information for persons concerned. The above systems are large-scale and requires high-cost, so it is impossible for general people to install this system easily. Considering on this situation, development of "FREQL" which aimed at epoch-making low cost and miniaturization is progressing to unite "UrEDAS" and "Compact UrEDAS", and to progress the processing time and presumed accuracy. FREQL, Fast Response Equipment against Quake Load, is pronounced _gfurekkulu_h and it means _gcoming shake_h in Japanese. On the other hand, the maximum acceleration is the physical value indispensable to grasp earthquake force and the seismic intensity is important to know the destructive power of an earthquake motion. Aiming to develop a small seismometer which can be installed in all residence and structures, instrumental seismic intensity corresponding to MMI was proposed and the small digital seismometer AcCo (Acceleration Collector) which can display the proposed objective seismic intensity data and the maximum acceleration on real time was developed. Although AcCo is small and cheap, it has an alarm function other than an earthquake observation function, and can widely use as not only for alarm but also for education. AcCo is the first seismometer as a new type of a realtime earthquake information equipment, which has a possibility of changing completely the view of future real-time earthquake disaster prevention.
UR: http://www.sdr.co.jp
DE: 7200 SEISMOLOGY
DE: 7212 Earthquake ground motions and engineering
DE: 7223 Seismic hazard assessment and prediction
DE: 7294 Instruments and techniques
SC: Seismology [S]
MN: 2003 Fall Meeting