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) The commitment of the Ministry of Ecology
In December 2004, Nelly Olin, then French minister of ecology and sustainable development, presented during a Cabinet meeting the main lines of the Programme National de Prévention du Risque Sismique ("National Seismic-Risk Prevention Programme") . Following the Sumatra tsunami, a fourth theme, dedicated to tsunami-risk prevention, was added to this programme, after it was observed that the French coasts were vulnerable to tsunamis "in several locations, in particular along France's West Indian and Mediterranean coasts".
Initiated in 2005 and placed under the direction of the Pollution and Risk Prevention Department ("Pollution and Risk Prevention Department"), this programme of action extends until 2011 and is structured around 3 main themes: evaluating the hazard, setting up a warning system, and raising public awareness.
The Pollution and Risk Prevention Department has commissioned BRGM to carry out two studies in order to better understand the French coasts' vulnerability to tsunamis.
(1) The creation of a tsunami database
BRGM was commissioned to create a computerized database on tsunamis to have touched France's départements (in metropolitan France, Guadeloupe, Martinique and La Réunion 49 ( * ) ). This catalogue may be consulted over the Internet and provides the following information for each tsunami:
- The date and time of the phenomenon;
- Its geographical location;
- The original cause of the phenomenon; BRGM established 8 categories: earthquakes, explosions, meteorites, landslides, volcanic eruptions, meteorological events, and unknown events. The meteorological criterium was chosen in order to distinguish between "real" tsunamis and tidal waves provoked by sea surges or cyclonal swells which are of meteorological origin; BRGM thereby avoids giving the impression of having overlooked these events;
- Its impact: the severity of damages is broken down into 5 categories;
- Its intensity, according to the international Sieberg-Ambraseys Tsunami Intensity Scale which rates tsunami intensity on a scale from 1 to 6 ("unknown" to "disastrous");
- The concerned basin (the Mediterranean, the Atlantic, etc.).
A "tsunami-observation window" allows users to indicate where the tsunami's impact was observed and to describe its dynamic effects (wave number and height, retreat distance and height, inundation distance and height, run-up height).
Another window indicates the epicentral characteristics of the earthquake that caused the tsunami. This information is taken from databases on France's seismic history managed by BRGM.
Finally, a bibliographical window was included, specifying the type of source used, its name, date of publication, title, author and place of publication, as well as the page(s) referring to the tsunami.
In late 2006, 21 events were integrated into the database. This catalogue is meant to contribute to the evaluation of the frequency and intensity of tsunamis on France's coasts.
* 49 French Polynesia was not included in the study.