The Railway Technical Research Institute (RTRI) is currently developing a new earthquake early alarm system in conjunction with the Japan Meteorological Agency (JMA) utilizing real-time information (Now-cast earthquake information) provided by the nationwide earthquake observation network of governmental organizations such as JMA.
      In the conventional early earthquake alarm system for Shinkansen, the magnitude and approximate location of an earthquake are estimated from the period of the initial P-wave measured at a single observation point, then an alarm is issued before the main tremor reaches the facilities. Conversely, under the new system the method of estimating earthquake data from the initial P-wave was re-examined, making full use of the latest seismological knowledge. As a result, a new method was developed for estimating the distance from the epicenter, the magnitude from the amplitude increase rate and maximum amplitude in the initial P-wave (Fig. 1).
      This method can estimate earthquake data more accurately than the conventional method while being less affected by earthquake noise, and is expected to become an earthquake specification estimation method for JMA's Now-cast earthquake information system.
      Techniques are also being studied for structural damage estimation utilizing the distribution of seismic intensity (Fig. 2), in which the seismic intensity is displayed in about 1km meshes. Such estimates will be delivered by the Japan Meteorological Agency around five minutes after an earthquake occurs.
      Plans are underway for a prototype RTRI system to carry out verification tests for practical use.