Estimation of Peak Ground Acceleration from Horizontal Rigid Body Displacement: A Case Study in Port-au-Prince, Haiti

Abstract

The M 7.0 Haiti earthquake of 12 January 2010 caused catastrophic damage and loss of life in the capital city of Port-au-Prince. The extent of the damage was primarily due to poor construction and high population density. The earthquake was recorded by only a single seismic instrument within Haiti, an educational seismometer that was neither bolted to the ground nor able to record strong motion on scale. The severity of near-field mainshock ground motions, in Port-au-Prince and elsewhere, has thus remained unclear. We present a detailed, quantitative analysis of the marks left on a tile floor by an industrial battery rack that was displaced by the earthquake in the Canape Vert neighborhood in the southern Port-au-Prince metropolitan region. Results of this analysis, based on a recently developed formulation for predicted rigid body displacement caused by sinusoidal ground acceleration, indicate that mainshock shaking at Canape Vert was approximately 0:5g, corresponding to a modified Mercalli intensity of VIII. Combining this result with the weakmotion amplification factor estimated from aftershock recordings at the site as well as a general assessment of macroseismic effects, we estimate the peak acceleration to be ≈0:2g for sites in central Port-au-Prince that experienced relatively moderate damage and where estimated weak-motion site amplification is lower than that at the Canape Vert site. We also analyze a second case of documented rigid body displacement, at a location less than 2 km from the Canape Vert site, and estimate the peak acceleration to be approximately 0:4g at this location. Our results illustrate how observations of rigid body horizontal displacement during earthquakes can be used to estimate peak ground acceleration in the absence of instrumental data.

Three‐dimensional dynamic rupture simulations across interacting faults: TheMw7.0, 2010, Haiti earthquake

“…For stations farther away from the rupture area, we find a PGA of (∼0.15 g) for PRY and PGv and less than 0.1 g for TPM which are still significantly lower than the other studies. In Port-au-Prince, our estimate of ∼0.1 g is close to that of Hough et al [2012], who used a rigid body displacement method to estimate a PGA of ∼0.2 g, significantly lower than those reported by Mavroeidis and Scotti [2013], Olson et al [2011], and the USGS shake map, where PGA is ∼0.3 g. The reason for this discrepancy is because PGA is usually controlled by high frequencies which our models could not generate since the highest frequency of the mesh is 2.3 Hz, and we had to filter the ground acceleration in order to reduce the digital noises. Also, these generated synthetics do not take into account any site effects, which have been shown to be important in Port-au-Prince in particular [Hough et al, 2010[Hough et al, , 2011, but are not considered in our modeling.…”

Simulation of broad-band strong ground motion for a hypothetical Mw 7.1 earthquake on the Enriquillo Fault in Haiti

“…Dynamic rupture studies have shown that complexities, such as fault roughness or stochastic stress asperities, can lead a rupture to reach higher fre-quencies (Oglesby & Day 2002;Shi & Day 2013, Lozos et al 2015. Furthermore, Hough et al (2012) used a rigid body displacement technique and inferred a PGA value of ∼0.2 g in Port-au-Prince, not too far off from that of Douilly et al (2015). The U.S. Geological Survey ShakeMap and Olson et al (2011) estimated the PGA in Port-au-Prince to be of the order of 0.3 g. Goodno et al (2011) correlated average structural damage at specific sites to estimated ground motion from other studies to infer a mean PGA in Port-au-Prince of the order of 0.13-0.47 g. Finally, Mavroeidis & Scotti (2013) used the coseismic slip distribution from Hayes et al (2010) to simulate broad-band ground motions by combining low-frequency synthetics generated using the discrete wavenumber representation method (Bouchon 1979) with high-frequency synthetics generated using the SBM (Papageorgiou & Aki 1983a,b;Papageorgiou 2003).…”

Seismic Design Value Evaluation Based on Checking Records and Site Geological Conditions Using Artificial Neural Networks

“…There exist various types of earthquake problems; a typical case study for estimating peak ground acceleration (PGA) and a detailed review of recent efforts in predictions can be seen in the previous literatures [3,4]. The present study focuses on the topic of using seismic recorded parameters and site soil conditions to evaluate the potential damage resulting from ground strong motions.…”