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CURRENT EVENTS at the OVSG

Volcanological and seismological Observatory of Guadeloupe


FOND-SAINT-DENIS, MARTINIQUE - LE HOUËLMONT, GUADELOUPE - 25 MARS 2010

Nouvelles avancées vers la création du système d’alerte aux tsunamis dans la Caraïbe.

Au Nicaragua, s’est tenue du 15 au 17 mars dernier, la cinquième session du Groupe de coordination intergouvernementale du système d’alerte aux tsunamis dans la Caraïbe(1). Un an après la dernière session qui s’était tenue en Martinique, cette rencontre apporte de nouvelles avancées vers la concrétisation de ce système d’alerte.

A Managua, les délégations des 28 pays et dépendances du bassin Caribéen ont acté la création du Programme d’alerte aux tsunamis pour la Caraïbe (CTWP – Caribe Tsunami warning Program) hébergé par l’Université de Porto Rico.

Ce Programme d’alerte préfigure la création d’un futur centre régional d’alerte aux tsunamis à Porto-Rico. Le Venezuela et le Nicaragua travaillent aussi à la mise en place d’un centre équivalant sur leur territoire.

Afin d’évaluer les capacités d’alerte actuelles, le Groupe de coordination intergouvernementale invite les pays de la zone à participer au prochain exercice de simulation de tsunami « CARIBE WAVE 2011 » qui aura lieu le 23 mars 2011.

Les Observatoires volcanologiques et sismologiques de Guadeloupe et de Martinique prévoient d’installer, d’ici à fin 2011, 6 marégraphes et 14 stations sismologiques répartis sur les îles de l’arc Antillais, dont 4 en partenariat avec le Seismic Research Center de l’Université des West Indies de Trinidad et Tobago. Le premier marégraphe(2) va d’ailleurs être mis en service dans le port de la Désirade dans les tous prochains mois. En plus des stations sismologiques de Fort-de-France en Martinique, et de Deshaies en Guadeloupe, ces équipements viendront compléter la contribution des îles Françaises au système d’alerte.

Enfin, en acceptant d’assurer une vice-présidence du Groupe de coordination intergouvernementale pour le système d’alerte aux tsunamis dans la Caraïbe, la France s’engage à promouvoir et à participer plus activement encore à ce processus de création auprès de la Commission océanographique intergouvernementale de l’UNESCO (COI).

La sixième réunion de ce Groupe de coordination intergouvernementale se tiendra en République Dominicaine, après l’exercice « CARIBE WAVE » fin mars 2011.
-FIN-

(1). Groupe de Coordination Intergouvernementale du système d’alerte aux Tsunamis et autres Risques Côtiers dans la Caraïbe et les Régions Adjacentes (ICG/CARIBE EWS-V).

(2). Marégraphe : instrument permettant de mesurer le niveau de la mer à un endroit donné utilisé pour valider ou non l’existence et la propagation d’un tsunami.



**La Guadeloupe et la Martinique subissent des chutes de cendres en provenance du volcan Soufriere Hills de Montserrat. Communique 12/02/2010 14h00 (GMT-4)**




Monthly bulletins of the OVSG



Official statements from the OVSG


Volcan

This page presents the ast official statement from the Volcanological and seismological Observatory of Guadeloupe (OVSG-IPGP), sent to a broad list of recipients:
Authorities and local communities, scientific organizations, media and private individuals registered on our e-mail list. The official statements provides mainly information on the seisms felt (of tectonic or volcanic origin) or an unusual telluric activity (Montserrat for example). For more complete information on the seismic and volcanic activity in Guadeloupe, consult our monthly bulletins. You can also consult the archives of the official statements from the OVSG.
To receive the OVSG official statements regularly please make a request to info@ovsg.univ-ag.fr



If you feel an Earthquake in Guadeloupe...


Apart from the periods of crisis, the OVSG records a monthly average of 60 regional Earthquake of tectonic origin, some of which can be felt.

Even if the principal characteristics of these seisms are known in the hour following the movement (epicenter localization, approximate magnitude and intensities), it is impossible to determine the real and in-situ intensity of seism in the various zones of the Guadeloupe, i.e. its exact effects on the population and the buildings in each place, without witness testimonies or an investigation on the ground. If you felt an Earthquake, you are invited to take a few minutes to report:

- At the OVSG by Tel.: 05 90 99 11 33, fax: 05 90 99 11 34 or e-mail: seisme@ovsg.univ-ag.fr

- Via the macro seism form at the BCSF on http://www.franceseisme.fr/

The data collected will also be used to improve our knowledge on the comportment of the various types of ground and buildings of Guadeloupe when subjected to earthquakes.


Note on the official statements regarding earthquakes


Since the beginning of the year 2005 and thanks to the development of a seismic waves attenuation law (baptized "B-Cubic" [ Beauducel et al, 2004 ]) the OVSG produces semi-automatic official statements (entitled "preliminary earthquakes report for Guadeloupe") with the objective to specify the probable maximum effects of a earthquakes on the people and buildings.

The B-Cubic law was integrated in an automatic calculation routine which starts as soon as a new event is located by the observatory. A document is thus produced and printed automatically if at least one commune in Guadeloupe suffers a maximum theoretical acceleration equal to 2 Mg (equivalent to intensity between I and II). The official statement is validated by the seismologist in duty and then sent to the authorities, communities and news media by e-mail or fax.

A preliminary reports has he following information:


- The date and hour, magnitude, location and the type of seism (tectonic or volcanic): this corresponds to the physical identification of the phenomenon;

- The closest commune to the epicenter and the distance to the hypocenter, as well as the value of the theoretical ground acceleration and the corresponding maximum intensity;

- The values of acceleration and intensity are estimated for all the communes in Guadeloupe where the earthquake could be felt and presented in descending order;

- A chart of the minor Antilles placing the earthquake's epicenter as well as the values of acceleration estimated by a color code;

- A table indicates the scale of human perceptions, the probable damage, accelerations and the intensities with an associated color code (largely inspired on the "Shake Maps" of the USGS [ 2001]).


The values of ground acceleration are given as an indication: they theoretical, maximum (Peak Ground Acceleration, for the "bad" grounds only) and are announced in order to sensitize the population to this physical indicator, less known, for example and by analogy, that the wind speed for the cyclones.

The values of intensity (modified MSK Scale) are also given as an indication: they express the probable effects of the earthquake on the people and the buildings in a given place. The actual values of intensity will be known only after analysis of collected reports and might require a detailed field investigation, since it depends on a great number of parameters mostly unknown at the time the preliminary official statement is drafted

The code of color associated to the intensity allows to visually translate the effects of the earthquake as well as possible: progressive color tone change along the whole of the scale, with blue for weak human perception with moderated effects, yellow-orange for the first property damages, and red for the more important damage.



Other current events


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Outre les communiqués d'information et les bulletins mensuels, l'OVSG vous propose:

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