Friday, February 19, 2010



Earthquake Details

Magnitude 7.0

Date-Time Tuesday, January 12, 2010 at 21:53:10 UTC
Tuesday, January 12, 2010 at 04:53:10 PM at epicenter
Time of Earthquake in other Time Zones

Location 18.457°N, 72.533°W

Depth 13 km (8.1 miles) set by location program

Region HAITI REGION

Distances 25 km (15 miles) WSW of PORT-AU-PRINCE, Haiti
130 km (80 miles) E of Les Cayes, Haiti
150 km (95 miles) S of Cap-Haitien, Haiti
1125 km (700 miles) SE of Miami, Florida

Location horizontal +/- 3.4 km (2.1 miles); depth fixed by
Uncertainty location program

Parameters NST=312, Nph=312, Dmin=143.7 km, Rmss=0.93 sec, Gp=
25°,
M-type=teleseismic moment magnitude (Mw), Version=9

Source USGS NEIC (WDCS-D)

Event ID us2010rja6



USGS Issues Assessment of Aftershock Hazards in Haiti Felt Reports Severe damage and casualties in the Port-au-Prince area. Felt throughout Haiti and the Dominican Republic, in Turks and Caicos Islands, southeastern Cuba, eastern Jamaica, in parts of Puerto Rico and the Bahamas, and as far as Tampa, Florida and Caracas, Venezuela.


Tectonic Summary

The January 12, 2010, Haiti earthquake occurred in the boundary region separating the Caribbean plate and the North America plate. This plate boundary is dominated by left-lateral strike slip motion and compression, and accommodates about 20 mm/y slip, with the Caribbean plate moving eastward with respect to the North America plate.

Haiti occupies the western part of the island of Hispaniola, one of the Greater Antilles islands, situated between Puerto Rico and Cuba. At the longitude of the January 12 earthquake, motion between the Caribbean and North American plates is partitioned between two major east-west trending, strike-slip fault systems -- the Septentrional fault system in northern Haiti and the Enriquillo-Plantain Garden fault system in southern Haiti.

The location and focal mechanism of the earthquake are consistent with the event having occurred as left-lateral strike slip faulting on the Enriquillo-Plantain Garden fault system. This fault system accommodates about 7 mm/y, nearly half the overall motion between the Caribbean plate and North America plate.

The Enriquillo-Plantain Garden fault system has not produced a major earthquake in recent decades. The EPGFZ is the likely source of historical large earthquakes in 1860, 1770, and 1751, though none of these has been confirmed in the field as associated with this fault.

Sequence of events possibly associated with the Enriquillio fault in 1751-1860 are as follows.

October 18, 1751: a major earthquake caused heavy destruction in the gulf of Azua (the eastern end of the Enriquillio Fault) which also generated a tsunami. It is unclear if the rupture occurred on the Muertos thrust belt or on the eastern end of Enriquillio Fault.

Nov. 21, 1751: a major earthquake destroyed Port Au Prince but was centered to the east of the city along the Cul de-Sac plain.

June 3, 1770: a major earthquake destroyed Port Au Prince again and appeared to be centered west of the city. As a result of the 1751 and 1770 earthquakes and minor ones in between, the authorities required building with wood and forbade building with masonry.

April 8, 1860: there was a major earthquake farther west accompanied by a tsunami.

Aftershock Report

As of 12:00 UTC January 28, the USGS NEIC has located 54 aftershocks of magnitude 4.5 or greater. Fifteen of these aftershocks have magnitudes of 5.0 or greater. The two largest aftershocks were each magnitude 5.9. The first M 5.9 aftershock occurred 7 minutes after the main shock on January 12 and the second M 5.9 event occurred at 11:03 UTC on January 20.

Earthquake Information for Caribbean
Tsunami Information Tsunami Information NOAA West Coast & Alaska Tsunami Warning Center NOAA Pacific Tsunami Warning Center The earthquake locations and magnitudes cited in these NOAA tsunami bulletins are very preliminary and may be superceded by USGS locations and magnitudes computed using more extensive data sets.

Tsunami Information Links


USGS Podcast Interview: Michael Blanpied, associate coordinator for the USGS Earthquake Hazards Program, answers questions about the earthquake, its severe shaking, and the possibility of additional hazards, such as landslides and a tsunami.



No comments:

Post a Comment