Systematic source, path and site effects on ground motion variability: the case study of Northern Italy

2017 ◽  
Vol 15 (11) ◽  
pp. 4563-4583 ◽  
Author(s):  
Giovanni Lanzano ◽  
Francesca Pacor ◽  
Lucia Luzi ◽  
Maria D’Amico ◽  
Rodolfo Puglia ◽  
...  
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Northern Italy ◽  
Ground Motion Variability

Seismic Noise-Based Strategies for Emphasizing Recent Tectonic Activity and Local Site Effects: The Ferrara Arc, Northern Italy, Case Study

2019 ◽  
Vol 176 (6) ◽  
pp. 2321-2347 ◽  
Author(s):  
A. Mantovani ◽  
N. Abu Zeid ◽  
S. Bignardi ◽  
G. Tarabusi ◽  
G. Santarato ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Site Effects ◽  
Northern Italy ◽  
Tectonic Activity ◽  
Local Site Effects ◽  
Local Site

scholarly journals Does the One-Dimensional Assumption Hold for Site Response Analysis? A Study of Seismic Site Responses and Implication for Ground Motion Assessment Using KiK-Net Strong-Motion Data

2019 ◽  
Vol 35 (2) ◽  
pp. 883-905 ◽  
Author(s):  
Marco Pilz ◽  
Fabrice Cotton
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Site Response ◽  
Three Dimensional ◽  
Strong Motion ◽  
Site Response Analysis ◽  
Response Analysis ◽  
One Dimensional ◽  
Ground Motion Variability ◽  
The One

The one-dimensional (1-D) approach is still the dominant method to incorporate site effects in engineering applications. To bridge the 1-D to multidimensional site response analysis, we develop quantitative criteria and a reproducible method to identify KiK-net sites with significant deviations from 1-D behavior. We found that 158 out of 354 show two-dimensional (2-D) and three-dimensional (3-D) effects, extending the resonance toward shorter periods at which 2-D or 3-D site effects exceed those of the classic 1-D configurations and imposing an additional amplification to that caused by the impedance contrast alone. Such 2-D and 3-D effects go along with a large within-station ground motion variability. Remarkably, these effects are found to be more pronounced for small impedance contrasts. While it is hardly possible to identify common features in ground motion behavior for stations with similar topography typologies, it is not over-conservative to apply a safety factor to account for 2-D and 3-D site effects in ground motion modeling.

The 2011 Mw 5.2 Lorca earthquake as a case study to investigate the ground motion variability related to the source model

2017 ◽  
Vol 15 (9) ◽  
pp. 3463-3482 ◽  
Author(s):  
Luca Moratto ◽  
Angela Saraò ◽  
Alessandro Vuan ◽  
Marco Mucciarelli ◽  
María-José Jiménez ◽  
...  
Keyword(s):  
Ground Motion ◽  
Source Model ◽  
Lorca Earthquake ◽  
Ground Motion Variability

scholarly journals Assessment of ground motion variability and its effects on seismic hazard analysis: a case study for iceland

2011 ◽  
Vol 9 (4) ◽  
pp. 931-953 ◽  
Author(s):  
Teraphan Ornthammarath ◽  
John Douglas ◽  
Ragnar Sigbjörnsson ◽  
Carlo Giovanni Lai
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Ground Motion Variability

Diffracted wavefield decomposition and multidimensional site effects in the Argostoli valley, Greece

2020 ◽  
Vol 224 (3) ◽  
pp. 1849-1869
Author(s):  
A Imtiaz ◽  
C Cornou ◽  
P-Y Bard ◽  
M Hobiger
Keyword(s):  
Surface Waves ◽  
Ground Motion ◽  
Rayleigh Waves ◽  
Site Effects ◽  
Velocity Structure ◽  
Low Frequency ◽  
Site Amplification ◽  
Processing Technique ◽  
Seismic Ground Motion ◽  
Ground Motion Variability

SUMMARY Effects of seismic ground motion induced by surface geology and geometry are known to be associated with the generation of a substantial proportion of surface waves. As a consequence, surface waves significantly contribute to ground-motion variability and site amplification. There is a growing body of literature recognizing that an understanding of physical patterns of the wavefield crossing a site is the key aspect to characterize and quantify them. However, this task remains technically challenging due to the complexity of such effects as well as the limitations of geophysical investigations, especially in case of small sedimentary valleys. The present study attempts to investigate the waves propagating across two 2-D dense seismic arrays from a number of earthquakes and explore the extent to which they are contributing to the multidimensional site effects. The arrays were deployed in the small-size, shallow alluvial valley of Koutavos-Argostoli, located in Cephalonia Island, Greece, and consisted of three-component velocimeters with interstation distances ranging from 5 to 160 m. A set of 46 earthquakes, with magnitudes between 2 and 5 and epicentral distances up to 200 km, was analysed by using an advanced seismic array processing technique, MUSIQUE. The phase velocity, backazimuth and energy of the dominant waves crossing the array were extracted, and their identification as Love or prograde/retrograde Rayleigh waves was obtained. The results clearly indicate a predominance of scattered surface waves (up to 60 per cent of total energy), mainly from the closest valley edges, above the fundamental frequency (∼1.5 Hz) of the valley. Love waves dominate the low-frequency wavefield (<3 Hz) while Rayleigh waves dominate some high-frequency bands. An excellent consistency is observed, in a given frequency range, among the dominance of the type of diffracted surface waves, group velocities estimated from the ground velocity structure and site amplification. The outcomes of this research provide a better understanding of the contribution of edge-diffracted surface waves and the 2-D/3-D site amplification at small and shallow alluvium valleys like Argostoli. The method applied here can be used to calibrate and validate 3-D models for simulating seismic ground motion.

scholarly journals Integrating dark diversity and functional traits to enhance nature conservation of epiphytic lichens: a case study from Northern Italy

2021 ◽  
Author(s):  
Diego Pires Ferraz Trindade ◽  
Meelis Pärtel ◽  
Carlos Pérez Carmona ◽  
Tiina Randlane ◽  
Juri Nascimbene
Keyword(s):  
Climate Change ◽  
Nature Conservation ◽  
Functional Traits ◽  
Growth Form ◽  
Northern Italy ◽  
Epiphytic Lichens ◽  
Mountain Areas ◽  
High Elevations ◽  
Harsh Conditions

AbstractMountains provide a timely opportunity to examine the potential effects of climate change on biodiversity. However, nature conservation in mountain areas have mostly focused on the observed part of biodiversity, not revealing the suitable but absent species—dark diversity. Dark diversity allows calculating the community completeness, indicating whether sites should be restored (low completeness) or conserved (high completeness). Functional traits can be added, showing what groups should be focused on. Here we assessed changes in taxonomic and functional observed and dark diversity of epiphytic lichens along elevational transects in Northern Italy spruce forests. Eight transects (900–1900 m) were selected, resulting in 48 plots and 240 trees, in which lichens were sampled using four quadrats per tree (10 × 50 cm). Dark diversity was estimated based on species co-occurrence (Beals index). We considered functional traits related to growth form, photobiont type and reproductive strategy. Linear and Dirichlet regressions were used to examine changes in taxonomic metrics and functional traits along gradient. Our results showed that all taxonomic metrics increased with elevation and functional traits of lichens differed between observed and dark diversity. At low elevations, due to low completeness and harsh conditions, both restoration and conservation activities are needed, focusing on crustose species. Towards high elevations, conservation is more important to prevent species pool losses, focusing on macrolichens, lichens with Trentepohlia and sexual reproduction. Finally, dark diversity and functional traits provide a novel tool to enhance nature conservation, indicating particular threatened groups, creating windows of opportunities to protect species from both local and regional extinctions.

Site effects of the Denis-Perron dam (SM-3): A case study in Eastern North America

2021 ◽  
pp. 875529302110194
Author(s):  
Daniel Verret ◽  
Denis LeBœuf ◽  
Éric Péloquin
Keyword(s):  
North America ◽  
Ground Motion ◽  
Site Effects ◽  
Transfer Functions ◽  
Ground Motions ◽  
Published Data ◽  
Eastern North America ◽  
Ground Acceleration ◽  
Large Dams ◽  
Moderate Seismicity

Eastern North America (ENA) is part of a region with low-to-moderate seismicity; nonetheless, some significant seismic events have occurred in the last few decades. Recent events have reemphasized the need to review ENA seismicity and ground motion models, along with continually reevaluating and updating procedures related to the seismic safety assessment of hydroelectric infrastructures, particularly large dams in Québec. Furthermore, recent researchers have shown that site-specific characteristics, topography, and valley shapes may significantly aggravate the severity of ground motions. To the best of our knowledge, very few instrumental data from actual earthquakes have been published for examining the site effects of hydroelectric dam structures located in eastern Canada. This article presents an analysis of three small earthquakes that occurred in 1999 and 2002 at the Denis-Perron (SM-3) dam. This dam, the highest in Québec, is a rockfill embankment structure with a height of 171 m and a length of 378 m; it is located in a narrow valley. The ground motion datasets of these earthquakes include the bedrock and dam crest three-component accelerometer recordings. Ground motions are analyzed both in the time and frequency domains. The spectral ratios and transfer functions obtained from these small earthquakes provide new insights into the directionality of resonant frequencies, vibration modes, and site effects for the Denis-Perron dam. The crest amplifications observed for this dam are also compared with previously published data for large dams. New statistical relationships are proposed to establish dam crest amplification on the basis of the peak ground acceleration (PGA) at the foundation.

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