From Source to Building Fragility: Post-event Assessment of the 2013 M7.1 Bohol Philippines Earthquake

2019 ◽  
pp. 101716EQS173M
Author(s):  
Muriel Naguit ◽  
Phil Cummins ◽  
Mark Edwards ◽  
Hadi Ghasemi ◽  
Bartolome Bautista ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Source Model ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Effective Implementation ◽  
Ideal Candidate ◽  
Post Disaster ◽  
Disaster Exposure

We use ground motion simulations of the 2013 Bohol Philippines earthquake along with a new post-disaster exposure/damage database to constrain building fragility and vulnerability. The large number of damaged buildings (>70,000) and the wide spread of seismic intensities caused by this earthquake make it an ideal candidate for such a study. An extensive survey was conducted leading to a robust description of over 25,000 damaged and undamaged structures. Ground motion fields were simulated using ground motion prediction equations and stochastic modeling, and the estimated and observed values were compared. The finite source model used in the simulation was based on the analysis of aftershocks and SAR data. The ground motions were associated with the empirical database to derive fragility and vulnerability models. Results indicate that the pattern of damage is best captured in the stochastic simulation. Constraints were placed on seismic building fragility and vulnerability models, which can promote more effective implementation of construction regulations and practices.

From Source to Building Fragility: Post-Event Assessment of the 2013 M7.1 Bohol, Philippines, Earthquake

2017 ◽  
Vol 33 (3) ◽  
pp. 999-1027 ◽  
Author(s):  
Muriel Naguit ◽  
Phil Cummins ◽  
Mark Edwards ◽  
Hadi Ghasemi ◽  
Bartolome Bautista ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Source Model ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Effective Implementation ◽  
Ideal Candidate ◽  
Post Disaster ◽  
Disaster Exposure

We use ground-motion simulations of the 2013 Bohol, Philippines, earthquake along with a new post-disaster exposure/damage database to constrain building fragility and vulnerability. The large number of damaged buildings (>70,000) and the wide spread of seismic intensities caused by this earthquake make it an ideal candidate for such a study. An extensive survey was conducted leading to a robust description of over 25,000 damaged and undamaged structures. Ground-motion fields were simulated using ground-motion prediction equations and stochastic modeling, and the estimated and observed values were compared. The finite source model used in the simulation was based on the analysis of aftershocks and SAR data. The ground motions were associated with the empirical database to derive fragility and vulnerability models. Results indicate that the pattern of damage is best captured in the stochastic simulation. Constraints were placed on seismic building fragility and vulnerability models, which can promote more effective implementation of construction regulations and practices.

scholarly journals Ground motions in urban Los Angeles from the 2019 Ridgecrest earthquake sequence

2021 ◽  
pp. 875529302110039
Author(s):  
Filippos Filippitzis ◽  
Monica D Kohler ◽  
Thomas H Heaton ◽  
Robert W Graves ◽  
Robert W Clayton ◽  
...  
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Ground Motions ◽  
Earthquake Sequence ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Velocity Models ◽  
Spectral Accelerations

We study ground-motion response in urban Los Angeles during the two largest events (M7.1 and M6.4) of the 2019 Ridgecrest earthquake sequence using recordings from multiple regional seismic networks as well as a subset of 350 stations from the much denser Community Seismic Network. In the first part of our study, we examine the observed response spectral (pseudo) accelerations for a selection of periods of engineering significance (1, 3, 6, and 8 s). Significant ground-motion amplification is present and reproducible between the two events. For the longer periods, coherent spectral acceleration patterns are visible throughout the Los Angeles Basin, while for the shorter periods, the motions are less spatially coherent. However, coherence is still observable at smaller length scales due to the high spatial density of the measurements. Examining possible correlations of the computed response spectral accelerations with basement depth and Vs30, we find the correlations to be stronger for the longer periods. In the second part of the study, we test the performance of two state-of-the-art methods for estimating ground motions for the largest event of the Ridgecrest earthquake sequence, namely three-dimensional (3D) finite-difference simulations and ground motion prediction equations. For the simulations, we are interested in the performance of the two Southern California Earthquake Center 3D community velocity models (CVM-S and CVM-H). For the ground motion prediction equations, we consider four of the 2014 Next Generation Attenuation-West2 Project equations. For some cases, the methods match the observations reasonably well; however, neither approach is able to reproduce the specific locations of the maximum response spectral accelerations or match the details of the observed amplification patterns.

A Ground-Motion Logic-Tree Scheme for Regional Seismic Hazard Studies

2017 ◽  
Vol 33 (3) ◽  
pp. 837-856 ◽  
Author(s):  
Özkan Kale ◽  
Sinan Akkar
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Motion Prediction ◽  
Motion Model ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Logic Tree ◽  
Ground Motion Model ◽  
The One

We propose a methodology that can be useful to the hazard expert in building ground-motion logic trees to capture the center and range of ground-motion amplitudes. The methodology can be used to identify a logic-tree structure and weighting scheme that prevents the dominancy of a specific ground-motion model. This strategy can be useful for regional probabilistic seismic hazard since logic-trees biased by a specific ground-motion predictive model (GMPE) may cause disparities in the seismic hazard for regions represented by large number of sites with complex seismic features. The methodology first identifies a suit of candidate ground-motion prediction equations that can cover the center, body and range of estimated ground motions. The GMPE set is then used for establishing alternative logic-trees composed of different weighting schemes to identify the one(s) that would not be biased towards a particular GMPE due to its sensitivity to the weights. The proposed methodology utilizes visual and statistical tools to assess the ground motion distributions over large areas that makes it more practical for regional hazard studies.

Ground Motions prediction Equations from a stochastic simulation approach for in-slab intermediate-depth earthquakes along the Hellenic subduction zone

2020 ◽  
Author(s):  
Harris Kkallas ◽  
Costas Papazachos ◽  
Dominikos Vamvakaris
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Large Magnitude ◽  
Intermediate Depth ◽  
Back Arc

<p>We have used a stochastic approach to simulate a large number of scenarios for in-slab intermediate-depth earthquakes in the southern Aegean Sea Hellenic subduction region, by applying an extended-source model using the EXSIM code. A large database of synthetic ground motion recordings for events with magnitudes in the range <strong>M</strong>6.0-8.5 has been compiled, covering the whole southern Aegean Benioff zone. For the stochastic simulations, we followed the approach developed in our previous works (Kkallas et al., 2018a,b), where we used the anelastic attenuation from the GMPEs modeling developed by Skarlatoudis et al. (2013) to constrain the different attenuation patterns and properties for the back-arc and fore-arc area. Simulation model parameters, such as stress parameters and attenuation parameters were also adopted from previous works, while for fault parameters we adopted the typical average focal mechanisms proposed by Papazachos et al. (2000), in agreement with the regional subduction tectonics. Estimates of expected ground motion measurements (PGA and PGV values) at different distances from different earthquakes have been employed to generate hybrid Ground-Motion Prediction Equations (GMPE). More specifically, we attempt to modify the existing Ground-Motion Prediction Equations (GMPE) from Skarlatoudis et al. (2013) for intermediate-depth earthquakes along the Hellenic Arc for large magnitude events (<strong>M</strong>>6.5), so that they can be efficiently used for Seismic Hazard assessment, as the original strong-motion dataset used for their development was lacking data in this magnitude range. Peak ground accelerations and velocities predicted by the EXSIM code are generally in very good agreement with the available GMPE results for magnitudes less than <strong>M</strong>7. However, significantly lower ground motions than those predicted by the GMPEs are predicted for large-magnitude events (<strong>M</strong>>7). Using the previous results, we propose a magnitude-dependent correction for the GMPE results both back-arc and along-arc ground motions. Moreover, we demonstrate how the final earthquake ground motion scenarios, as well as the modified GMPEs affect both deterministic and probabilistic seismic hazard analysis. This work has been partly supported by the HELPOS (MIS 5002697) project.</p>

Estimating Unknown Input Parameters when Implementing the NGA Ground-Motion Prediction Equations in Engineering Practice

2011 ◽  
Vol 27 (4) ◽  
pp. 1219-1235 ◽  
Author(s):  
James Kaklamanos ◽  
Laurie G. Baise ◽  
David M. Boore
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Distance Measures ◽  
Motion Prediction ◽  
Engineering Practice ◽  
Unknown Input ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Input Parameters

The ground-motion prediction equations (GMPEs) developed as part of the Next Generation Attenuation of Ground Motions (NGA-West) project in 2008 are becoming widely used in seismic hazard analyses. However, these new models are considerably more complicated than previous GMPEs, and they require several more input parameters. When employing the NGA models, users routinely face situations in which some of the required input parameters are unknown. In this paper, we present a framework for estimating the unknown source, path, and site parameters when implementing the NGA models in engineering practice, and we derive geometrically-based equations relating the three distance measures found in the NGA models. Our intent is for the content of this paper not only to make the NGA models more accessible, but also to help with the implementation of other present or future GMPEs.

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