-------- 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