Preliminary conclusions:
Large earthquakes on side-slip fault zones (horizontal separation) like the one in Port-au-Prince which remain inactive for a long time, tend to trigger others, thus producing sequences of destructive events like this. is well documented on the North Anatolia blackout in Turkey. We must therefore deduce that the rupture of the segments of the fault in the East from Léogâne to the south-east of Port-au-Prince and to the West (on the Tiburon Peninsula) is likely to produce further earthquakes in the decades to come.
(See detailed article below.)
Earthquake January 12, 2010
Source: Tectonics Lab. - Institut de Physique du Globe de Paris (IPGP)
Preliminary assessment of the Haiti earthquake of January 12, 2010,
(January 25, 2010)
Preliminary Conclusions:
The earthquake of January 12, 2010 ruptured a segment of the left-side Enriquillo fault, a fault that would account for a significant fraction (~ 7mm / yr [2]) of the movement between the Caribbean and North American plates. To the west of Haiti, the Enriquillo fault extends into the sea towards Jamaica where it becomes the fault of the Jardin de la Banane Plantain. The Enriquillo fault, which extends for about 300 km on the island of South Hispaniola, was already identified as a potential source of earthquakes M> 7 [2].
Before the 2010 event, this anomaly had not produced significant earthquakes for at least two centuries. At least one event (June 3, 1770) of the sequence that rocked southern Hispaniola in the 18th century, probably occurred on the Enriquillo fault, with reported effects resembling those of the 2010 event. Only one The relatively short segment of the fault (~ 30 km, possibly 50 km, Figure 2) appears to have been activated by the event on January 12.
Large earthquakes on side-slip fault zones (horizontal separation) which remain inactive for a long time, tend to trigger others, thus producing sequences of destructive events as is well documented on the Anatolia blackout. North in Turkey. We therefore deduced that the rupture of the segments in the East the source of the January 12 earthquake (i.e. immediately southeast of Port-au-Prince) and the West (on the Tiburon Peninsula) is likely to occur in the decades to come. As of the date of writing (January 25), conclusive evidence to determine the exact length of the fracture segment, the location of surface jumps (if any), and the amount of good coseismic at the surface, is lacking.
However, the first InSAR results may help define the western end of the fracture, which apparently stopped in the eastern region of the extraction-separation of Lake Miragoâne. The lack of evidence of clear co-seismic surface fracture and measurable offsets along the fault, in the available high-resolution images taken after the earthquake, suggests that the surface ground displacement was less than 0.5 - 1 meter or is distributed over a large area. The determination of new limitations of the deformation field (in particular InSAR interferograms covering the eastern part of the fracture and GPS measurements), higher resolution images (aerial photographs, topography acquired with Lidar, for example) and a field survey are obviously necessary.
Finally, the absence of geomorphic studies and the digging of paleo-seismological trenches along the Enriquillo fault, implies that its average rate (of displacement) is not known on the geological time scale, nor its seismic history. is not established with precision.