-------- Original Message -------- Subject: SILS Information Bulletin 10 01 Executive Summary on Haiti Earthquake Date: Fri, 5 Mar 2010 10:35:32 -0700 From: Sheryle J Jackson <[log in to unmask]> To: undisclosed-recipients:; SILS Information Bulletin *Number 10-01 Haiti Earthquake of January 12, 2010* *Date: March 5, 2010* A field reconnaissance in Haiti lead by a five-member team with expertise in seismology and earthquake engineering has revealed a number of factors that led to catastrophic losses of life and property during the January 12, 2010, Mw 7.0 earthquake. The field study was conducted from January 26 to February 3, 2010, and included investigations in Port-au-Prince and the heavily damaged communities to the west, including Léogâne, Grand Goâve, Petite Goâve, and Oliver. The wide range of buildings damaged by the January 12, 2010, earthquake suggests that the ground motions contained seismic energy over a wide range of frequencies. Another earthquake of similar magnitude could strike at any time on the eastern end of the Enriquillo Fault, directly to the south of Port-au-Prince. Reconstruction must take this hazard into account. The four portable seismographs installed by the team recorded a series of small aftershocks. As expected, the ground motions recorded at a hard-rock site contained a greater proportion of high frequencies than the motions recorded at a soil site. Two of the stations continue to monitor seismic activity. It appears that the widespread damage to residences and commercial and government buildings was attributable to a great extent to the lack of earthquake-resistant design. In many cases, the structural types, member dimensions, and detailing practices were inadequate to resist strong ground motions. These vulnerabilities may have been exacerbated by poor construction practices. Reinforced concrete frames with concrete block masonry infill appeared to perform particularly poorly. Structures with light (timber or sheet metal) roofs performed better compared to structures with concrete roofs and slabs. For more of this report which is available only on the web, control and click on the picture above. Additional information is also available through the Earthquake Science Center in Northern California. */_http://quake.wr.usgs.gov_/* For information on other USGS products, contact the USGS Science Information and Library Services (SILS) at: 1-888-ASK-USGS, or online through the USGS store at: */_http://store.usgs.gov_/* Sheryle Girk-Jackson 303 202 4176, FAX 303 202 4633, email: [log in to unmask] <mailto:[log in to unmask]> Sheryle J. Girk-Jackson Technical Information Specialist/Business Acquisitions USGS/ESIC