scholarly journals Impact of ground motion characterization on conservatism and variability in seismic risk estimates

1996 ◽  
Author(s):  
R.T. Sewell ◽  
G.R. Toro ◽  
R.K. McGuire
Keyword(s):  
Ground Motion ◽  
Seismic Risk ◽  
Risk Estimates ◽  
Motion Characterization

On Canadian methodologies of probabilistic seismic risk estimation

1979 ◽  
Vol 69 (5) ◽  
pp. 1549-1566
Author(s):  
D. H. Weichert ◽  
W. G. Milne
Keyword(s):  
Ground Motion ◽  
Seismic Risk ◽  
Risk Estimation ◽  
Historical Earthquakes ◽  
Extreme Value ◽  
Probabilistic Methods ◽  
Average Value ◽  
Risk Estimates ◽  
The Stability ◽  
Comparison Of The Results

abstract Three probabilistic methods for the estimation of seismic risk have been used in Canada. A reevaluation of the extreme value method shows no advantages over the average value method of Milne and Davenport. Conceptual improvements in the underlying assumptions of the latter method are a constrained release of historical earthquakes from their presumed epicenters and the averaging of earthquake rates over variable periods. Risk estimation can then proceed as suggested by Cornell. Comparison of the results of this modification of the average number method shows similar results as the Milne and Davenport average value method. The stability of risk estimates against new earthquakes is improved, but sensitivities at typical sites toward unavoidable deterministic elements in the model are similar to the older method. For certain site-source-seismicity combinations probabilistic estimates of ground motion could become almost quasi-deterministic.

scholarly journals Current Challenges and Future Trends in Analytical Fragility and Vulnerability Modeling

2019 ◽  
Vol 35 (4) ◽  
pp. 1927-1952 ◽  
Author(s):  
Vitor Silva ◽  
Sinan Akkar ◽  
Jack Baker ◽  
Paolo Bazzurro ◽  
José Miguel Castro ◽  
...  
Keyword(s):  
Ground Motion ◽  
Empirical Data ◽  
Current Practice ◽  
Earthquake Damage ◽  
Future Trends ◽  
Risk Estimates ◽  
Ground Motion Records ◽  
Vulnerability Functions ◽  
Selection Of

The lack of empirical data regarding earthquake damage or losses has propelled the development of dozens of analytical methodologies for the derivation of fragility and vulnerability functions. Each method will naturally have its strengths and weaknesses, which will consequently affect the associated risk estimates. With the purpose of sharing knowledge on vulnerability modeling, identifying shortcomings in the existing methods, and recommending improvements to the current practice, a group of vulnerability experts met in Pavia (Italy) in April 2017. Critical topics related to the selection of ground motion records, modeling of complex real structures through simplified approaches, propagation of aleatory and epistemic uncertainties, and validation of vulnerability results were discussed, and suggestions were proposed to improve the reliability and accuracy in vulnerability modeling.

Contribution for seismic hazard assessment with local scale focus on Durrës (Albania) and damage observation after the ML 5.4, 21st September 2019 earthquake

2020 ◽  
Author(s):  
Marco Mancini ◽  
Iolanda Gaudiosi ◽  
Redi Muci ◽  
Maurizio Simionato ◽  
Klodian Skrame
Keyword(s):  
Seismic Hazard ◽  
Cultural Heritage ◽  
Ground Motion ◽  
Seismic Risk ◽  
Preliminary Results ◽  
Joint Research Project ◽  
Single Station ◽  
Noise Measurements ◽  
The City ◽  
2D Array

<p>The city of Durrës was recentely struck by a Mw 6.2 mainshock event (http://cnt.rm.ingv.it/event/23487611) that caused considerable damage and 51 victims. The city is located on an actively seismotectonic belt where seismic catalogues report few past events with magnitude higher than 6.</p><p>Surface geology is generally considered to influence the ground motion recorded on site. The analysis of the influence of local effects on seismic response at ground surface appears relevant also considering that Durrës is a densely populated city prone to high seismic risk and is characterized by several important archeological and cultural heritage sites.</p><p>Preliminary results obtained from recent geophysical in-situ measurements and geological surveys, carried out in Durrës after the ML 5.4, 21<sup>st</sup> September 2019 event, are presented with the aim of providing new elements for the assessment of local seismic hazard and following a comprehensive approach to the modifications induced by the site.</p><p>Twenty-nine single-station noise measurements, processed through the HVSR technique, two MASW surveys and two 2D array measurements were performed. Results from noise measurements define a zone eastward of the historical centre, where the characteristics of surficial soil layers are responsible for modification to the seismic demand. In particular, HVSR curves in this area show amplification higher than 4 at a period higher than 1s. Moreover, on this location a surface waves-velocity profile obtained from a joint inversion of Rayleigh curves from MASW and 2D array with ellipticity individuates a class D soil, EC8 sensu, corresponding to marshy soil of very poor geotechnical quality. These data may be considered as key elements in the site-specific response analyses, i.e. realized according to the international codes (EC8, NEHRP), which allow to quantify the expected ground motion. These results are potentially useful for  correlating  construction typologies and period vibration of the buildings with the site amplification.</p><p>In addition, a damage survey was carried out in one of the most damaged zones after the 21<sup>st</sup> September 2019 earthquake. Because of the following stronger event of the 26<sup>th</sup> November 2019, we think that these preliminary results may provide useful information for the post-earthquake reconstruction and enhancement of the urban resilience.</p><p>                The activities are carried out wihin the framework of the CNR/MOES Joint research project “Seismic risk assessment in cultural heritage cities of Albania” in the biennium 2018-2019 (https://www.cnr.it/en/bilateral-agreements/agreement/60/moes-ministry-of-education-and-sport-of-the-republic-of-albania).</p>

scholarly journals Hazard-consistent seismic losses and collapse capacities for light-frame wood buildings in California and Cascadia

2021 ◽  
Author(s):  
Robert E. Chase ◽  
Abbie B. Liel ◽  
Nicolas Luco ◽  
Zach Bullock
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Risk ◽  
Ground Motions ◽  
Spectral Shape ◽  
Economic Losses ◽  
Frequency Content ◽  
Crustal Earthquakes ◽  
Design Values ◽  
American Society

AbstractWe evaluate the seismic performance of modern seismically designed wood light-frame (WLF) buildings, considering regional seismic hazard characteristics that influence ground motion duration and frequency content and, thus, seismic risk. Results show that WLF building response correlates strongly with ground motion spectral shape but weakly with duration. Due to the flatter spectral shape of ground motions from subduction events, WLF buildings at sites affected by these earthquakes may experience double the economic losses for a given intensity of shaking, and collapse capacities may be reduced by up to 50%, compared to those at sites affected by crustal earthquakes. These differences could motivate significant increases in design values at sites affected by subduction earthquakes to achieve the uniform risk targets of the American Society of Civil Engineers (ASCE) 7 standard.

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