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Brief introductory note on earthquake hazards in Haiti

Sergio Mora1 Introduction On January 12th 2010, Haiti was struck by a Mw=7.0 earthquake. This seismic event, whose extent has yet to be precisely determined, has caused significant damage in terms of people killed, injured, trauma, social, economic and environmental losses, as well as another step back to the recovery and development process of Haiti. Added to the recent hydro-meteorological and political events occurred during the last two decades at least, this earthquake adds a significant drive towards further suffering of the population and jeopardy to the stability of Haiti. This unfortunate situation must be taken as an opportunity to induce a strong drive towards the improvement of an integral risk management policy, and particularly on earthquakes hazards and vulner-ability. This is not the first time that strong earthquakes strike the island of Hispaniola and Haiti in particular. The following paragraphs will attempt to recall the causes, consequences and history of some of the documented events. The advances already gained in updating and modernizing the National Risk and Disaster Manage-ment Plan, as well and the National Intervention Plan (National Emergency Response Plan) through the World Bank-sponsored Projet d’Urgence de Gestion du Risque et des Désastres, Composante 2 (P090159). Don IDA-H1430-HA – H3530-HA might of course continue to be the main instrument to the cause. Tectonic setting Haiti shares the island of Hispaniola (Quisqueya) with the Dominican Republic, east of Cuba and Jamaica and west of Puerto Rico. This portion of the Greater Antilles is located at the northern edge of the Caribbean tectonic plate, at its boundary with the North-American plate (Figure 1).

Figure 1. Island of Hispaniola. Observe its location near the northern edge of the Caribbean tectonic plate

1 Consultant to the World Bank; sergiomo@hotmail.com

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The limit between the two tectonic plates is defined by a strike-slip left-lateral motion, since the Caribbean plate moves relatively to the east-northeast (Figure 2) and the North-America plate moves relatively to the west. This kind of interaction induces a strong liberation of mechanical energy, typically and frequently ma-terialized as earthquakes.

Figure 2. Relative vectorial displacement of the Caribbean tectonic plate (Calais; 2001)

The boundary between the two plates is not defined by a single border line, but instead by a zone where sev-eral tectonic fault systems have been identified, some of them with evidences of current seismic activity, others showing evidences of historic and/or pre-historic activity (Figure 3).

Figure 3. Main tectonic features at the island of Hispaniola and epicenters showing of the most recent concentrations of

earthquake events.

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There is historic evidence of several destructive earthquakes in the island of Hispaniola. It is to be noticed that according with these records, the January 12th, 2010 earthquake is not, by far, the event with the highest magnitude and intensities. Haiti and Dominican Republic have been struck repeatedly by earthquakes during the last four and a half centuries (Table 1).

Table. Most important seismic events recorded in the island of Hispaniola and Haiti. DATE Type Magnitude Localisation Morts Blessés Affectés Sans logis Commentaires

1564 Séisme (2) 7 + 6,2 Conception de la Vega, Santo Do-mingo

Détruite

1615 Séisme 7,0 Santo Domingo Dégâts

1684 Séisme 6,5 Santo Domingo, Ázua Dégâts

1691 Séisme 7,0 Santo Domingo Dégâts 9 nov 1701 Séisme (2) 6,0 Léogane Dégâts

15 sep 1751 Séisme 8 + 7,5 Port-au-Prince, Santo Domingo, Ázua

Détruites

18-25 oct 1751 Séisme 7,5 Port-au-Prince Dégâts

3 jun 1770 Séisme Port-au-Prince,

Léogane 250 250 Détruite

29 juil 1785 Séisme Port-au-Prince Dégâts 20 nov 1818 Séisme Cap Henri 5 5 Dégâts

7 mai 1842 Séisme et tsuna-mi CapH & Pt-de-Px 2500 2500 150 Détruite

7 mai 1842 Séisme 8,0 Port-au-Prince Dégâts 8 mai 1842 Séisme 6,9 Cap-Haïtien Dégâts

17 jun 1881 Séisme Ile entière Dégâts

23 sep 1887 Séisme (2) et tsunami 7,0 + 7,75 Môle Saint-Nicolas,

Cap Haïtien 5500 Détruites

22-sep 1904 Séisme et tsuna-mi 6,5 Port-de-Paix Dégâts

11 mai 1910 Séisme Cap-Haïtien Dégâts

6 oct 1911 Séisme et liqué-faction 7,1 Hinche, San Juan,

Azua 12 30 Dégâts

6-7 sept 1912 Séisme Plaissance Dégâts 27 mai 1924 Séisme Port-de-Paix 3 3 Dégâts

4 août 1946 Séismes (3), tsunami, liqué-faction

7 + 8,1 + 7,4 Puerto Plata Détruite

27 oct 1952 Séisme Anse à Veau, Nip-pes 6 6 Dégâts

20 avr 1962 Séisme 6,75 Cap Haïtien 0 0 0 0 10-

11mai 1991 Séisme Jean Rabel 3e s. 35 35 Dégâts

16 oct 1992 Secousse Cap-Haïtien 2 déc 1992 Secousse Delmas 0 0 0 0 8 mar 1993 Secousse Carrefour Feuilles 0 0 0 0 19 fév 1994 Secousse Port-au-Prince 0 0 0 0 1 mars 1994 Secousse Port-au-Prince 0 0 0 0

9 aoû 1995 Secousse Port-au-Prince 0 0 0 0 6-7 fév 1996 Séisme Chambellan 0 0 150 150 Dégâts 22-sep 2002 Séisme 6,5 Puerto Plata 12 300 2000 150 Dégâts

12 jan 2010 Séisme 7,0 Port-au-Prince et autres Détruite

Sources: Bulletins de l'Observatoire du Petit Collège Saint-Martial (1906-1966) ; Woodring, 1994 OFDA-USAID, 1984 ; Mora, 1986, 1991 ; Calais, 2001 ; McCann, 2001

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The most important historic earthquakes have been generated along the northern Plate Boundary, the Sub-duction process, Cibao-Septentrional, Ocoa-Cerca la Source and the Enriquillo-Cul de Sac-Plantain fault systems (Figure 4).

Figure 4. Location of the epicenters of the main earthquake events in the island of Hispaniola (Calais 2001).

It is important to notice that earthquakes occurring in the Dominican side of the island can generate damages on the Haitian side and vice-versa (Figure 5).

Figure 5. Examples of isoseismic maps from earthquakes in the island of Hispaniola (Mora 1986a and 1986b)

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The most important earthquake events, that is, the ones with magnitude Ms, Mw ≥ 7.0 (McCann 2001, Calais 2001), produced by the different seismogenic sources in and near the island of Hispaniola are listed in Table 2. It is possible to observe that, regardless of their source, ten major events have occurred since the 16th cen-tury with intervals of 19 to 76 years, and with an average interval of 49.5 years. Sixty-four years had passed since the largest previous earthquake occurred (Puerto Plata, Cibao, 1946; Mw=8.1) before the January 12th 2010 event Table 2. Most important destructive earthquake events having occurred in the island of Hispaniola since the 16th century

(McCann 2001, Calais 2001)

The January 12th, 2010 event was generated by the Enriquillo-Cul de Sac-Plantain fault systems (Figure 6), southwest of Port-of-Prince. Its hypocenter was shallow (less than 10 km) and had a reverse-oblique with a strike-slip sinestral component focal mechanism. These type of shallow events are particularly destructive, since most of its energy is concentrated in a small volume of Earth’s crust and projected upwards rapidly.

Figure 6. Epicenter of the January 12, 2010 (NEIC), produced by one of the main active tectonic faults of southern

Haiti: the Enriquillo-Cul de Sac-Plantain fault system.

Figure 7. Simulated ground deformation derived from the Haiti, January 12th 2010 earthquake (Calais, pers. Com. 2010)

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The maximum intensities (Modified Mercalli) of this event, as surveyed and analyzed be NEIC, range from IMM = II to IX (Figure 8) and concentrate along Haiti’s Southern Peninsula (Departements of Sud and Sud-ouest).

Figure 8. Intensities recorded and analysed (IMM) by NEIC.

Additional information gathered from the newspapers, TV journals and phone interviews in Haiti and Do-minican Republic, correlate well with NEIC’s analysis, although maximum intensities may have reach IMM = X (Figure 9). It is also interesting to notice that there is a relatively high concentration of higher intensities along the areas covered by alluvial, lacustrine, colluvial and marine soils.

Figure 9. Modified Mercalli intensities (IMM) obtained from newscasts and phone interviews

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Extensive damage to reinforced and non-reinforced buildings has started to appear in newscasts. Houses, public services, governmental, private commercial buildings as well as roads, public utilities, infrastructure and productive activities have bear important losses that remain to be assessed and evaluated (Figures 10). Most worrying of all are important damages recorded on hospitals, fire stations, health centers, water, sanita-tion and school facilities.

Figure 9. Palais National d’Haïti

Bibliography Calais, E. 2001. Vers un projet "Aléa sismique en Haïti". CNRS ; Géosciences Azur. Sophia Antipolis, Fran-

ce. Unpublished report; 11pp. Calais, E., Perrot, J., and Mercier de Lépinay, B. 1998. Strike-slip tectonics and seismicity along the

Northern Caribbean plate boundary from Cuba to Hispaniola, Geol. Soc. of Amer. Special Paper 326, Edited by J.F. Dolan and P. Mann,125-142.

DeGraff, J; Bryce, R; Jibson, R; Mora, S; Rogers, C. 1989. Landslides: Their extent in the Caribbean. XXVIII International Geological Congress, Washington, D.C. In: Landslides: extent and economic sig-nificance. Editorial Balkema, Rotterdam.

Dixon, T., F. Farina, C. Demets, P. Jansma, P. Mann, and E. Calais. 1998. Relative motion between the Car-ibbean and North American plates and related boundary zone deformation based on a decade of GPS ob-servations, J. Geophys. Res., 103, 15157-15182.

Mora, S. 1986a. Étude de reconnaissance des menaces naturelles dans le basin du Haut Artibonite, Haïti. Projet Frontalier OEA/DDR/GH-INGEOSA.

Mora, S. 1986b. Estudio de reconocimiento de las amenazas naturales, región fronteriza (occidental), República Dominicana. Proyecto de desarrollo fronterizo. OEA/GobRD; Fase III, ONAPLAN, 90pp.

Mora, S. 1992. Estudio preliminar de la erosión acelerada, localidad de Bánica, Elías Piña, República Dominicana. Proyecto Desarrollo Fronterizo OEA/DDR/ONAPLAN-INDRHI, 96pp.

Mora, S. 1993. Análisis geomorfológico de reconocimiento, sector Dominicano de las cuencas de los ríos Artibonite, Libón y Macasía. Proy. Desarrollo Fronterizo OEA/GRD; ONAPLAN-INDRHI. 80p; 1987.

Mora, S. 2003. La gestión del riesgo en la República Dominicana: Relación y aportes del Banco Interamericano de Desarrollo. Oficina de Evaluación y Representación en República Dominicana. Banco Interamericano de Desarrollo. OVE-RE2/EN2-COF/CDR. 35pp.

Mora, S. 2009. Revison du Plan National d’Intervention (future Plan National de Réponse aux Urgences) de la République d’Haïti. Rapport inédit de mission. Projet d’Urgence de Gestion du Risque et des Désas-tres, Composante 2 (P090159). Don IDA-H1430-HA – H3530-HA. Port-au-Prince, 29 novembre – 5 dé-cembre. 36pp.