SENAT
Report n° 117 (2007-2008) by M. Roland COURTEAU, Senator (for the parliament office for the evaluation of scientific and technological choices) - Appendix to the minutes of the 7 December 2007 session
Disponible au format Acrobat (21 Moctets)
B. A RISK THAT BEGAN TO BE TAKEN SERIOUSLY IN THE OTHER BASINS FOLLOWING THE TSUNAMI OF 26 DECEMBER 2004
While the scientific community and several international organizations 27 ( * ) were already interested in tsunamis phenomena before the Sumatra catastrophe struck, it must be admitted that the general public only became aware of this hazard then.
1. The "shock" of Sumatra
Several factors explain the veritable shock provoked by the tsunami that ravaged the Indian Ocean on 26 December 2004:
- Its uniqueness, with regard to both its size and the number of victims. With a magnitude of 9.3, the earthquake which provoked the tsunami was the second most violent earthquake ever recorded, with a fracture zone 1,200 kilometres long. In addition, the tsunami claimed 250,000 victims and displaced more than one and a half million persons on the coasts of twelve countries.
- The date on which this event occurred and the immense media coverage it attracted: the Christmas season is supposed to be a happy and festive time of the year. Therefore, this natural disaster strongly affected the world's population, generating an unprecedented show of generosity: private individuals donated more than €1.5 billion to humanitarian organizations. The media certainly contributed to this generosity, by broadcasting only hours after the tsunami struck footage for the most part recorded by private individuals via their digital cameras or cell phones, which showed this wave submersing the beaches and seaside resorts. This event, therefore, quickly took on a planetary dimension, all the more so considering the many Western tourists who figured among the tsunami's victims.
Also, the fact that the Indian Ocean had, up until then, been considered a relatively tsunami-safe zone generated increased public awareness.
a) The realization that all basins are vulnerable
Statistically speaking, the Indian Ocean is considered the safest ocean basin with regard to tsunamis, since it accounted for only 4% of tsunamis generated during the 20 th century. However, the tsunami of 26 December 2004 claimed more victims than all other (known) tsunamis combined since ancient times.
In addition, it served as a reminder that certain regions that had not been struck by a tsunami in human memory had nevertheless been completely devastated in the distant past, with the volcanic eruption on Santorini being a good example.
b) Shedding light on the shortcomings of the tsunami-risk prevention system
The Sumatra tsunami above all revealed enormous shortcomings with regard to mitigating the tsunami risk.
First of all, the images showing tourists playing in those areas where the sea had withdrawn revealed the public's complete ignorance of this phenomenon and its manifestations.
Secondly, scientists were surprised by the violence of the earthquake that had generated the tsunami and it became clear that, outside the Pacific zone, the tsunami phenomenon was not well understood due to insufficient research in this domain. For example, few catalogues of past tsunamis per basin had been published and the potential sources of tsunamis had not been systematically recorded and even less frequently analyzed in order to establish tsunami-exposure maps.
Finally, many observed that if a warning system had been in place, thousands of human lives could have been saved. The international community, under the aegis of UNESCO, therefore decided to complete the existing tsunami warning system and extend it to all zones.
* 27 In particular, UNESCO via the IOC.