PURPOSE: To enable alarmed inhabitants in a dangerous region to take required action against disasters in the time till arrival of an earthquake by detecting the initial shock of an earthquake wave and forecasting and calculating various elements of the earthquake in real time to transmit them to the dangerous region.

CONSTITUTION: The initial shock level of the earthquake wave detected by an earthquake wave detecting means 1 is calculated based on past statistical data by a signal processing means 2 to forecast various elements of the earthquake corresponding to the initial shock level in real time. Forecasted data is transmitted to an earthquake dangerous region by an automatic transmission means 3, and a signal processing means 6 receives this data to discriminate various elements of the earthquake and determines an alarm command corresponding to the initial shock level of the earthquake wave. The determined alarm command is sent to the earthquake dangerous region through a radio transmission means 7, and a portable receiver 8 receives the alarm command to report the occurrence of the earthquake to inhabitants, who carry this receiver, in the early stage.