Site Characterization and Site Response in Port-au-Prince, Haiti

Abstract

Waveform analysis of aftershocks of the M w 7.0 Haiti earthquake of 12 January 2010 reveals amplification of ground motions at sites within the Cul de Sac valley in which Port-au-Prince is situated. Relative to ground motions recorded at a hard-rock reference site, peak acceleration values are amplified by a factor of approximately 1.8 at sites on low-lying Mio-Pliocene deposits in central Portau-Prince and by a factor of approximately 2.5-3 on a steep foothill ridge in the southern Port-au-Prince metropolitan region. The observed amplitude, predominant periods, variability, and polarization of amplification are consistent with predicted topographic amplification by a steep, narrow ridge. A swath of unusually high damage in this region corresponds with the extent of the ridge where high weak-motion amplifications are observed. We use ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) imagery to map local geomorphology, including characterization of both near-surface and of smallscale topographic structures that correspond to zones of inferred amplification.

Rapid Damage Mapping for the 2015Mw 7.8 Gorkha Earthquake Using Synthetic Aperture Radar Data from COSMO–SkyMed and ALOS-2 Satellites

“…Because of the sensitivity of DPM over urban and vegetated areas is different, the profile was selected only within urban area identified with the Global Urban Footprint derived from the German Aerospace Center's (DLR's) X-band TerraSAR-X SAR data. age and topography as was observed in Port-au-Prince after the 2010 M w 7.0 Haiti earthquake (Hough et al, 2010(Hough et al, , 2011. Figure 8 shows the profiles of ALOS-2 DPM before taking a threshold and the SRTM DEM in an urban area north of Kathmandu, masked using the Global Urban Footprint (Esch et al, 2013).…”

Critical Parameters Affecting Bias and Variability in Site-Response Analyses Using KiK-net Downhole Array Data

“…Site-response analyses are used to estimate the ground motion at the surface, as a function of the properties of the soil profile and the bedrock ground motion at the base of the soil profile (Kramer, 1996). As observed in many historic and recent earthquakes, the softer materials near the free surface influence damage patterns over short distances (Borcherdt, 1970;Boatwright et al, 1991;Hanks and Brady, 1991;Bakir et al, 2002;Bradley and Cubrinovski, 2011;Hough et al, 2011). Accurate modeling of nonlinear soil behavior is an important component of seismic hazard assessment.…”

Challenges in Predicting Seismic Site Response with 1D Analyses: Conclusions from 114 KiK‐net Vertical Seismometer Arrays

“…The influence of near-surface geologic materials on seismic wave amplitudes -site response -can greatly influence damage patterns over short distances (Borcherdt, 1970;Boatwright et al, 1991;Hanks and Brady, 1991;Bakir et al, 2002;Hough et al, 2011;Bradley and Cubrinovski, 2011). Site-specific analyses of near-surface ground-motion amplification are required to quantify the seismic hazard for many engineering design projects.…”