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TitreNew observations of earthquake site response and seismic attenuation in Haiti
AuteurCassidy, J F; Al-Khoubbi, I; Rogers, G C; Bent, A; McCormack, D; Andrews, C
SourceSeismological Society of America Annual Meeting, Abstracts; Seismological Research Letters vol. 81, no. 3, 2010, 1 pages
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100014
RéunionSeismological Society of America Annual Meeting; Portland, OR; US; avril 21-23, 2010
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetssecousses séismiques; magnitudes des séismes; risque de tremblement de terre; dégât causés par les tremblements de terre; géophysique
ProgrammeÉvaluations ciblées des dangers dans l'Ouest du Canada, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
On January 12, 2010, a devastating magnitude 7 earthquake struck near Port au Prince, Haiti. This earthquake caused widespread destruction, killing more than 200,000 people. Some of the key questions to be addressed in the coming months and years are: what contributed to the damage distribution? What was the role of local site response? What was the role of seismic attenuation? What was the role of earthquake source effects? In this study we utilise three-component broadband data, and strong motion recordings from three recently-deployed Canadian seismograph stations in Haiti to examine the potential contributions of local site effects and seismic attenuation. H/V ratios computed for more than 25 earthquakes of magnitude 1 to 5 show consistent site response. At Leogane, closest to the mainshock and on young, soft, Quaternary soils (and one of the hardest hit areas), several significant resonant peaks are observed in H/V ratios at frequencies between 1 and 5 Hz. In contrast, a bedrock (thin-soil) site on a hillside near Port au Prince shows relatively flat response. In Jacmel, resonant peaks are observed at higher frequencies (7-10 Hz). A preliminary comparison with damage patterns shows that the amplification peaks at lower frequencies may be associated with higher damage. Preliminary comparisons of ground shaking as a function of distance suggests that attenuation relationships derived for the nearby islands of Jamaica and Puerto Rico are applicable to Haiti.