By applying knowledge and spontaneously making use of what is available, a 10-year-old girl saved more than 100 tourists from the Tsunami in December 2004.  The story was widely circulated by the media:  While holidaying with her parents in Thailand, the girl noticed that the water level dropped suddenly. Other tourists watched in amazement, how the tide appeared to rush out very fast. The girl, however, having recently heard about Tsunamis when the teacher had explained earthquakes and related natural phenomena, realized what this unusual event meant, and alerted everyone in reach. The beach and the nearby hotel were evacuated immediately before the giant wave crashed ashore.

Telecommunication was not involved - all communication was verbal. The early warning was based on nothing but local observation and its interpretation, using recently acquired information. This interpretation led to immediate live-saving action.

In most cases, however, the knowledge necessary to interpret an observation is not locally available.

Early warning is possible only, if observations can be communicated to those who have the knowledge to interpret them, and if public warnings can then be communicated to those potentially vulnerable.

Telecommunication is not likely to reach each individual, but the multiplication factor shown in the above example was more than hundredfold. Many popular beaches have cellular phone coverage, and each tourist having his or her phone switched on while on such a beach, will warn everyone within reach. A technology, ready available, for such early warning will be discussed in a later module of this course.