Analysis of Site Response and Building Damage Distribution Induced by the 31 October 2002 Earthquake at San Giuliano di Puglia (Italy)

2013 ◽  
Vol 29 (2) ◽  
pp. 497-526 ◽  
Author(s):  
Rodolfo Puglia ◽  
Marco Vona ◽  
Peter Klin ◽  
Chiara Ladina ◽  
Angelo Masi ◽  
...  
Keyword(s):  
Seismic Response ◽  
Site Response ◽  
Spectral Element ◽  
Site Amplification ◽  
Damage Distribution ◽  
Numerical Predictions ◽  
Definition Of ◽  
Subsoil Model ◽  
Molise Earthquake ◽  
Input Motion

This paper concerns the analysis of the site amplification that significantly influenced the non-uniform damage distribution observed at San Giuliano di Puglia (Italy) after the 2002 Molise earthquake (MW = 5.7). In fact, the historical core of the town, settled on outcropping rock, received less damage than the more recent buildings, founded on a clayey subsoil. Comprehensive geotechnical and geophysical investigations allowed a detailed definition of the subsoil model. The seismic response of the subsoil was analyzed through 2-D finite-element and 3-D spectral-element methods. The accuracy of such models was verified by comparing the numerical predictions to the aftershocks recorded by a temporary seismic network. After calibration, the seismic response to a synthetic input motion reproducing the main shock was simulated. The influence of site amplification on the damage distribution observed was finally interpreted by combining the predicted variation of ground motion parameters with the structural vulnerability of the buildings.

Simulation-based site amplification model for shallow bedrock sites in Korea

2021 ◽  
pp. 875529302098198
Author(s):  
Muhammad Aaqib ◽  
Duhee Park ◽  
Muhammad Bilal Adeel ◽  
Youssef M A Hashash ◽  
Okan Ilhan
Keyword(s):  
Linear Models ◽  
Site Response ◽  
Site Amplification ◽  
One Dimensional ◽  
Nonlinear Component ◽  
Nonlinear Site Response ◽  
Simulation Based ◽  
Linear And Nonlinear ◽  
Input Motion ◽  
Nonlinear Components

A new simulation-based site amplification model for shallow sites with thickness less than 30 m in Korea is developed. The site amplification model consists of linear and nonlinear components that are developed from one-dimensional linear and nonlinear site response analyses. A suite of measured shear wave velocity profiles is used to develop corresponding randomized profiles. A VS30 scaled linear amplification model and a model dependent on both VS30 and site period are developed. The proposed linear models compare well with the amplification equations developed for the western United States (WUS) at short periods but show a distinct curved bump between 0.1 and 0.5 s that corresponds to the range of site natural periods of shallow sites. The response at periods longer than 0.5 s is demonstrated to be lower than those of the WUS models. The functional form widely used in both WUS and central and eastern North America (CENA), for the nonlinear component of the site amplification model, is employed in this study. The slope of the proposed nonlinear component with respect to the input motion intensity is demonstrated to be higher than those of both the WUS and CENA models, particularly for soft sites with VS30 < 300 m/s and at periods shorter than 0.2 s. The nonlinear component deviates from the models for generic sites even at low ground motion intensities. The comparisons highlight the uniqueness of the amplification characteristics of shallow sites that a generic site amplification model is unable to capture.

Estimation of Site Amplification from Geotechnical Array Data Using Neural Networks

2021 ◽  
Author(s):  
Daniel Roten ◽  
Kim B. Olsen
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Site Response ◽  
Site Amplification ◽  
Data Driven ◽  
Vertical Array ◽  
The Neural Network ◽  
Simplifying Assumptions ◽  
The Mean ◽  
Fully Connected

ABSTRACT We use deep learning to predict surface-to-borehole Fourier amplification functions (AFs) from discretized shear-wave velocity profiles. Specifically, we train a fully connected neural network and a convolutional neural network using mean AFs observed at ∼600 KiK-net vertical array sites. Compared with predictions based on theoretical SH 1D amplifications, the neural network (NN) results in up to 50% reduction of the mean squared log error between predictions and observations at sites not used for training. In the future, NNs may lead to a purely data-driven prediction of site response that is independent of proxies or simplifying assumptions.

Correspondence between Site Amplification and Topographical, Geological Parameters: Collation of Data from Swiss and Japanese Stations, and Neural Networks-Based Prediction of Local Response

2021 ◽  
Author(s):  
Paolo Bergamo ◽  
Conny Hammer ◽  
Donat Fäh
Keyword(s):  
Frequency Response ◽  
Large Scale ◽  
Site Response ◽  
Low Frequency ◽  
Field Measurements ◽  
Site Amplification ◽  
Local Response ◽  
Regional Variability ◽  
Individual Site ◽  
Digital Elevation

ABSTRACT We address the relation between seismic local amplification and topographical and geological indicators describing the site morphology. We focus on parameters that can be derived from layers of diffuse information (e.g., digital elevation models, geological maps) and do not require in situ surveys; we term these parameters as “indirect” proxies, as opposed to “direct” indicators (e.g., f0, VS30) derived from field measurements. We first compiled an extensive database of indirect parameters covering 142 and 637 instrumented sites in Switzerland and Japan, respectively; we collected topographical indicators at various spatial extents and focused on shared features in the geological descriptions of the two countries. We paired this proxy database with a companion dataset of site amplification factors at 10 frequencies within 0.5–20 Hz, empirically measured at the same Swiss and Japanese stations. We then assessed the robustness of the correlation between individual site-condition indicators and local response by means of statistical analyses; we also compared the proxy-site amplification relations at Swiss versus Japanese sites. Finally, we tested the prediction of site amplification by feeding ensembles of indirect parameters to a neural network (NN) structure. The main results are: (1) indirect indicators show higher correlation with site amplification in the low-frequency range (0.5–3.33 Hz); (2) topographical parameters primarily relate to local response not because of topographical amplification effects but because topographical features correspond to the properties of the subsurface, hence to stratigraphic amplification; (3) large-scale topographical indicators relate to low-frequency response, smaller-scale to higher-frequency response; (4) site amplification versus indirect proxy relations show a more marked regional variability when compared with direct indicators; and (5) the NN-based prediction of site response is the best achieved in the 1.67–5 Hz band, with both geological and topographical proxies provided as input; topographical indicators alone perform better than geological parameters.

scholarly journals A hybrid model for mapping simplified seismic response via a GIS-metamodel approach

2014 ◽  
Vol 14 (7) ◽  
pp. 1703-1718 ◽  
Author(s):  
G. Grelle ◽  
L. Bonito ◽  
P. Revellino ◽  
L. Guerriero ◽  
F. M. Guadagno
Keyword(s):  
Seismic Hazard ◽  
Seismic Response ◽  
Hybrid Model ◽  
Computational Models ◽  
Site Response ◽  
Seismic Hazard Assessment ◽  
Physical Parameters ◽  
Seismic Zone ◽  
Acceleration Response ◽  
Good Correspondence

Abstract. In earthquake-prone areas, site seismic response due to lithostratigraphic sequence plays a key role in seismic hazard assessment. A hybrid model, consisting of GIS and metamodel (model of model) procedures, was introduced aimed at estimating the 1-D spatial seismic site response in accordance with spatial variability of sediment parameters. Inputs and outputs are provided and processed by means of an appropriate GIS model, named GIS Cubic Model (GCM). This consists of a block-layered parametric structure aimed at resolving a predicted metamodel by means of pixel to pixel vertical computing. The metamodel, opportunely calibrated, is able to emulate the classic shape of the spectral acceleration response in relation to the main physical parameters that characterize the spectrum itself. Therefore, via the GCM structure and the metamodel, the hybrid model provides maps of normalized acceleration response spectra. The hybrid model was applied and tested on the built-up area of the San Giorgio del Sannio village, located in a high-risk seismic zone of southern Italy. Efficiency tests showed a good correspondence between the spectral values resulting from the proposed approach and the 1-D physical computational models. Supported by lithology and geophysical data and corresponding accurate interpretation regarding modelling, the hybrid model can be an efficient tool in assessing urban planning seismic hazard/risk.

The ground effects of the Skopje July 26, 1963 earthquake

1969 ◽  
Vol 59 (1) ◽  
pp. 1-22
Author(s):  
Apostol Poceski
Keyword(s):  
Resonant Frequency ◽  
Seismic Response ◽  
Abrupt Change ◽  
Soil Layer ◽  
Soil Amplification ◽  
Damage Distribution ◽  
Predominant Period ◽  
Clear Explanation ◽  
Ground Effects

Abstract Damage distribution in Skopje can be explained in terms of the seismic response of surficial soils. There exists a generally good correlation between the distribution of damage, the thickness of the surficial soil layer, and the predominant periods of microtremors. The most heavily damaged region is covered with about 20 to 30 meters of alluvium, and the predominant period of this alluvium is about 0.36 seconds. The alluvium in this heavily damaged region probably was shaken near its resonant frequency, and soil amplification may have reached three. The greatest destruction was recorded along a belt which is defined by an abrupt change of the thickness of the alluvium. However, heavy destruction was also recorded on the shallow alluvium side, and no clear explanation exists for this.

Earthquake site response estimation: A weak-motion case study

1992 ◽  
Vol 82 (6) ◽  
pp. 2283-2307
Author(s):  
E. H. Field ◽  
K. H. Jacob ◽  
S. E. Hough
Keyword(s):  
Site Response ◽  
Spectral Ratio ◽  
Large Degree ◽  
One Dimensional ◽  
Loma Prieta Earthquake ◽  
Cross Spectrum ◽  
Downward Bias ◽  
Dimensional Models ◽  
The Cross ◽  
Input Motion

Abstract Using weak-motion recordings of aftershocks of the 1989 Loma Prieta earthquake recorded in Oakland, California, near the failed Nimitz Freeway, two methods have been applied to estimate the site response of an alluvium site and three mud-over-alluvium sites. The first estimate is the traditional spectral ratio, and the second utilizes the cross spectrum. Recordings obtained at a nearby bedrock site are used as estimates of the sediment site input motions. While the two site response estimates produce similar peaks and troughs, there is an approximate factor of 2 difference in amplitudes. This discrepancy is evidence that there is a much greater level of noise than would be expected from the pre-event ambient noise. We interpret this as signal-generated noise produced by scattering from heterogeneities, which causes the true sediment site input to differ significantly from the bedrock site recording. Given this level of noise, the cross-spectrum estimate suffers a severe downward bias (by a factor of 2 in this study) and should probably not be used when the input motion is estimated from a bedrock site recording. The spectral-ratio estimates are relatively unbiased, but the level of noise introduces a large degree of uncertainty. Therefore, inferences about site response from individual spectral ratios should probably be avoided. On the other hand, ensemble averages of the estimates significantly reduce the scatter to reveal resonances that agree quite well in frequency and overall shape with those of one-dimensional models whose parameters were determined independently. A discrepancy of higher observed amplitudes than predicted by theory remains unexplained but most likely results from the effects of boundary layer topography, which are not accounted for by the simple one-dimensional models.

scholarly journals Physical stratigraphy and geotechnical properties controlling the local seismic response in explosive volcanic settings: the Stracciacappa maar (central Italy)

2020 ◽  
Vol 80 (1) ◽  
pp. 179-199
Author(s):  
M. Moscatelli ◽  
G. Vignaroli ◽  
A. Pagliaroli ◽  
R. Razzano ◽  
A. Avalle ◽  
...  
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Central Italy ◽  
Volcanic Event ◽  
Ground Motion Amplification ◽  
Local Seismic Response ◽  
Single Station ◽  
Seismic Scenarios ◽  
Physical Stratigraphy ◽  
Subsoil Model

AbstractNowadays, policies addressed to prevention and mitigation of seismic risk need a consolidated methodology finalised to the assessment of local seismic response in explosive volcanic settings. The quantitative reconstruction of the subsoil model provides a key instrument to understand how the geometry and the internal architecture of outcropping and buried geological units have influence on the propagation of seismic waves. On this regard, we present a multidisciplinary approach in the test area of the Stracciacappa maar (Sabatini Volcanic District, central Italy), with the aim to reconstruct its physical stratigraphy and to discuss how subsoil heterogeneities control the 1D and 2D local seismic response in such a volcanic setting. We first introduce a new multidisciplinary dataset, including geological (fieldwork and log from a 45-m-thick continuous coring borehole), geophysical (electrical resistivity tomographies, single station noise measurements, and 2D passive seismic arrays), and geotechnical (simple shear tests performed on undisturbed samples) approaches. Then, we reconstruct the subsoil model for the Stracciacappa maar in terms of vertical setting and distribution of its mechanical lithotypes, which we investigate for 1D and 2D finite element site response analyses through the application of two different seismic scenarios: a volcanic event and a tectonic event. The numerical modelling documents a significant ground motion amplification (in the 1–1.5 Hz range) revealed for both seismic scenarios, with a maximum within the centre of the maar. The ground motion amplification is related to both 1D and 2D phenomena including lithological heterogeneity within the upper part of the maar section and interaction of direct S-waves with Rayleigh waves generated at edges of the most superficial lithotypes. Finally, we use these insights to associate the expected distribution of ground motion amplification with the physical stratigraphy of an explosive volcanic setting, with insights for seismic microzonation studies and local seismic response assessment in populated environments.

Significance of site natural period effects for linear site amplification in central and eastern North America: Empirical and simulation-based models

2020 ◽  
Vol 36 (1) ◽  
pp. 87-110 ◽  
Author(s):  
Youssef M. A. Hashash ◽  
Okan Ilhan ◽  
Behzad Hassani ◽  
Gail M. Atkinson ◽  
Joseph Harmon ◽  
...  
Keyword(s):  
North America ◽  
Site Response ◽  
Reference Conditions ◽  
Site Amplification ◽  
Empirical Models ◽  
Response Analysis ◽  
Eastern North America ◽  
Natural Period ◽  
Motion Models ◽  
Simulation Based

This article evaluates linear simulation-based and empirical site amplification models including site natural period dependency parameters to account for the distinctive amplification behavior near site fundamental frequencies resulting from the sharp impedance contrast between soil and underlying hard bedrock in central and eastern North America (CENA). The simulation-based amplification models are developed using 581,685 frequency-domain linear analyses generated from a parametric study and include VS30-scaling and site natural period ( Tnat) parameters. The empirical models are derived from residuals analyses of ground-motion models for two reference conditions: B/C boundary ( VS30 = 760 m/s) and CENA hard-rock condition ( VS = 3000 m/s). The simulation-based and empirical models are compared for 8 site profiles in CENA to measured horizontal-to-vertical (H/V) component response spectral (RS) ratios, the mean of linear simulations for similar sites, and one-dimensional (1D) linear site response analysis for four of these sites. Comparisons between observed and estimated site amplification behaviors highlight model dependency on Tnat in CENA. Model consistencies and differences related to the distinct linear amplification features near site fundamental frequency are discussed.

The 1983 Liege Earthquake: Damage Distribution and Site Effects

1990 ◽  
Vol 6 (4) ◽  
pp. 713-737 ◽  
Author(s):  
D. Jongmans ◽  
M. Campillo
Keyword(s):  
Site Effects ◽  
Large Scale ◽  
Site Response ◽  
Dominant Frequency ◽  
Small Scale ◽  
Eastern United States ◽  
Frequency Range ◽  
Damage Distribution ◽  
Damage Data ◽  
The City

On November 8, 1983, a moderate magnitude (Ml=4.9) earthquake struck Liege (Belgium). A damage study has shown that site effects at different scales have played an important role in amplifying ground motion. On a large scale, the damage distribution has been determined by the presence of a large Carboniferous syncline beneath the city as shown by 2D numerical modeling. On a small scale, the main damage concentrations can be correlated with local superficial deposits which have amplified ground motions in the frequency range of buildings. A geophysical survey was carried out to measure the shear wave velocity of the different formations. Site response computations were made at numerous sites in order to estimate the possible amplification and to compare the results with the damage. It was shown that the spectral amplifications computed in the dominant frequency range of the buildings are consistent with the damage data. In very affected areas, 1D amplifications of 4 to 6 were obtained and in some cases 2D effects may have occurred. The Liege earthquake, taking place in the intraplate region of Northwestern Europe, presents a significant interest to other similar areas as the eastern United States.

Sign in / Sign up

Export Citation Format

Share Document