A reliable computerized litho-morphometric model for development of 3D maps of Topographic Aggravation Factor (TAF): the cases of East Mountain (Utah, USA) and Port au Prince (Haiti)

Grelle, G.; Wood, Charles D.; Bonito, L.; Sappa, Giuseppe; Revellino, Paola; Rahimi, Salman; Guadagno, Francesco M.

doi:10.1007/s10518-017-0272-x

Cited by 8 publications

(10 citation statements)

References 55 publications

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“…Indeed, according to the well-accepted (and proven) rule established by [28], the amplified wavelength is similar to the entire width of a hill (with free slopes to both sides of the crest), which is here equal to 700 m. Considering the likely average Vs of 1100-1300 m/s beyond a 30-m depth for the hill material (as measured by [29]), the frequency over which the hill amplifies ground motion is in the order of 1.6-1.9 Hz. This reasoning partly fits with the results from [8], who predicted a topographical frequency peak at 2.5-3 Hz with an amplification factor of two. Around the HM station (Figure 13), the Tromino HVSR noise curves generally display larger amplitudes between 1.5 Hz and 20 Hz.…”

Section: S-waves Hvsr Resultssupporting

confidence: 89%

“…They highlighted a significant variability in the amplification distribution of the layers below Hotel Montana. More recently, Grelle et al [8] proposed models computing both the topographical aggravation factor and soil amplification, which were implemented for two locations in Haiti: the station HCEA and the station HHMT. They also argued that the amplification at Hotel Montana is due to topographical and soft soil amplification.…”

Section: Introductionmentioning

confidence: 99%

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Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part A: Geophysical-Seismological Survey Results

Ulysse

Boisson

Prépetit³

et al. 2018

Geosciences

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Abstract:After the M = 7.0 Haiti earthquake in 2010, many teams completed seismic risk studies in Port-au-Prince to better understand why this not extraordinarily strong event had induced one of the most severe earthquake disasters in history (at least in the Western World). Most highlighted the low construction quality as the main cause for the disaster, but some also pointed to possible soil and topographic amplification effects, especially in the lower and central parts of Port-au-Prince (e.g., close to the harbor). However, very detailed local studies of such site effects have not been completed yet. A Belgian-Haitian collaboration project was established in order to develop a detailed local seismic hazard study for Gros-Morne hill located in the district of Pétion-Ville, southeast of Port-au-Prince. In order to have a better understanding of the amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, site effects were investigated by using near surface geophysical methods. The horizontal to vertical spectral ratio technique was applied to ambient vibrations and earthquake data, and multichannel analysis of surface waves and P-wave refraction tomography calculation were applied to seismic data. Standard spectral ratios were computed for the S-wave windows of the earthquake data recorded by a small temporary seismic network. Electrical resistivity tomography profiles were also performed in order to image the structure of the subsurface and detect the presence of water, if any. The spectral ratio results generally show low to medium (1.5-6) resonance amplitudes at one or several different resonance frequencies (for the same site), between 0.5 and 25 Hz. At most of the investigated sites, the fundamental resonance frequency varies between 7 and 10 Hz. By using the multichannel surface wave analyses of the seismic data, we were able to determine shear wave velocities ranging between 200 and 850 m/s, up to a depth of about 15-20 m. From the refraction analysis, we were able to delineate P-waves velocities of 500 to 1500-2000 m/s at the studied sites. The outputs were locally compared with the resistivity data from the electrical profiles. Thus, the overall data indicate a moderate site effect at Gros-Morne hill, with a great variability in site amplification distribution. Initial estimates of local site effects were made on the basis of those outputs and the earthquake recordings. Our results are finally discussed with respect to outputs and interpretations that had been published earlier for the same site. Those results only partly confirm the strong seismic amplification effects highlighted by previous papers for this hill site, which had been explained by the effects of the local topographic and soil characteristics.

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Section: S-waves Hvsr Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part A: Geophysical-Seismological Survey Results

Ulysse

Boisson

Prépetit³

et al. 2018

Geosciences

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“…In order to account for possible topography-related amplification effects, a number of seismic codes, as Eurocode 8 (CEN 2004) and NTC18 in Italy (Ministero delle Infrastrutture e dei Trasporti 2018), have introduced topographic amplification coefficients for simplified morphological conditions. Recently the efforts are focused on the development of more sophisticated estimators, based on the availability of digital elevation models (DEM) and equivalent uniform rock stiffness estimates (Grelle et al 2018). Zhou et al (2020) adopt the back-propagation neural network technique for the derivation of a ground motion amplification model based on topographic geometrical features estimated from the DEM.…”

Section: Introductionmentioning

confidence: 99%

Investigation of topographic site effects using 3D waveform modelling: amplification, polarization and torsional motions in the case study of Arquata del Tronto (Italy)

Baron

Primofiore

Klin

et al. 2021

Bull Earthquake Eng

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The combined effect of topography and near-surface heterogeneities on the seismic response is hardly predictable and may lead to an aggravation of the ground motion. We apply physics-based numerical simulations of 3D seismic wave propagation to highlight these effects in the case study of Arquata del Tronto, a municipality in the Apennines that includes a historical village on a hill and a hamlet on the flat terrain of an alluvial basin. The two hamlets suffered different damage during the 2016 seismic sequence in Central Italy. We analyze the linear visco-elastic seismic response for vertically incident plane waves in terms of spectral amplification, polarization and induced torsional motion within the frequency band 1–8 Hz over a 1 km2 square area, with spatial resolution 25 m. To discern the effects of topography from those of the sub-surface structure we iterate the numerical simulations for three different versions of the sub-surface model: one homogeneous, one with a surficial weathering layer and a soil basin and one with a complex internal setting. The numerical results confirm the correlation between topographic curvature and amplification and support a correlation between the induced torsional motion and the topographic slope. On the other hand we find that polarization does not necessarily imply ground motion amplification. In the frequency band above 4 Hz the topography-related effects are mainly aggravated by the presence of the weathering layer, even though they do not exceed the soil-related effects in the flat-topography basin. The geological setting below the weathering layer plays a recognizable role in the topography-related site response only for frequencies below 4 Hz.

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“…For this site, several previous studies referred to possible site amplification in order to explain the severe damage in some zones on top of GrosMorne hill, and along the southern slope caused by the 2010 main event, as evidenced by [5]. References [5][6][7][8] argue that local amplification effects are likely to have contributed to severe shaking and related destruction, such as the collapse of Hotel Montana on top of the hill (see location in Figure 1b); they attribute those effects both to topographical and soft soil amplification. In addition, reference [7] highlights the significant variability in soil response that is probably related to a complex subsurface structure.…”

Section: Introductionmentioning

confidence: 99%

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

Ulysse

Boisson

Prépetit³

et al. 2018

Geosciences

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This paper presents the general results in terms of maps, as well as geological and numerical models of a site effect study, that aimed at a better understanding of the ground motion amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, Haiti, which might have influenced the 2010 event damage pattern in that area. These maps and models are based on multiple geophysical-seismological survey outputs that are presented, in detail, in Part A of this publication. Those outputs include electrical resistivity tomography sections, P-wave velocity profiles, S-wave logs, estimates of the fundamental resonance frequency for many locations, as well as earthquake recordings at three sites and associated site amplification assessment for the top of the hill. Related results are discussed in Part A with respect to outputs and interpretations that had been published earlier by other research teams for the same site. Our results only partly confirm the strong seismic amplification effects highlighted by some of the previous studies for this hill site, which had been attributed to the influence of local topographic and soil characteristics on seismic ground motion. Here, we focus on the imaging of different site effect components over the entire survey area; we present maps of shear wave velocity variations, of changing fundamental resonance frequencies, and of related estimates of soft soil/rock thickness, of peak spectral amplitudes, and of ambient ground motion polarization. Results have also been compiled within a 3D surface-subsurface model of the hill, which helps visualize the geological characteristics of the area, which are relevant for site effect analyses. From the 3D geomodel, we extracted one 2D geological section along the short-axis of the hill, crossing it near the location of Hotel Montana on top of the hill, which had been destroyed during the earthquake, and has now been rebuilt. This cross-section was used for dynamic numerical modelling of seismic ground motion, and for related site amplification calculation. The numerical results are compared with the site amplification characteristics that had been estimated from the ambient vibration measurements and the earthquake recordings.

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A reliable computerized litho-morphometric model for development of 3D maps of Topographic Aggravation Factor (TAF): the cases of East Mountain (Utah, USA) and Port au Prince (Haiti)

Cited by 8 publications

References 55 publications

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part A: Geophysical-Seismological Survey Results

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part A: Geophysical-Seismological Survey Results

Investigation of topographic site effects using 3D waveform modelling: amplification, polarization and torsional motions in the case study of Arquata del Tronto (Italy)

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

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