Pub Date : 2024-09-19DOI: 10.1177/87552930241272612
Da Pan, Hiroyuki Miura
This study proposed a deep-neural-network (DNN) model for seismic ground motion prediction by utilizing a unified strong motion database by the National Research Institute for Earth Science and Disaster Resilience, and earthquake horizontal-to-vertical spectral ratio (EHVR) database in Japan. The model aims to enhance the accuracy of predictions by incorporating the EHVRs for complementing site effects, and utilizing existing ground motion prediction equations (GMPE) as the base model for source and propagation path effects. The hybrid approach enables the prediction of peak ground accelerations (PGAs), peak ground velocities (PGVs), and 5% damped absolute acceleration response spectra (SAs). After classifying the training and test sets from the database, the trained DNN models were applied on the test set to evaluate the performance of the predicted results. The accuracy assessment by the residuals, R-squared ( R2), and root mean square error (RMSE) between the predicted and observed values in the test set revealed the superior performance of the proposed model compared with the traditional GMPE with proxy-based site effects such as V S30s especially in predicting both the spectral amplitude and shape of SAs.
{"title":"Deep-neural-network model for predicting ground motion parameters using earthquake horizontal-to-vertical spectral ratios","authors":"Da Pan, Hiroyuki Miura","doi":"10.1177/87552930241272612","DOIUrl":"https://doi.org/10.1177/87552930241272612","url":null,"abstract":"This study proposed a deep-neural-network (DNN) model for seismic ground motion prediction by utilizing a unified strong motion database by the National Research Institute for Earth Science and Disaster Resilience, and earthquake horizontal-to-vertical spectral ratio (EHVR) database in Japan. The model aims to enhance the accuracy of predictions by incorporating the EHVRs for complementing site effects, and utilizing existing ground motion prediction equations (GMPE) as the base model for source and propagation path effects. The hybrid approach enables the prediction of peak ground accelerations (PGAs), peak ground velocities (PGVs), and 5% damped absolute acceleration response spectra (SAs). After classifying the training and test sets from the database, the trained DNN models were applied on the test set to evaluate the performance of the predicted results. The accuracy assessment by the residuals, R-squared ( R<jats:sup>2</jats:sup>), and root mean square error (RMSE) between the predicted and observed values in the test set revealed the superior performance of the proposed model compared with the traditional GMPE with proxy-based site effects such as V<jats:sub> S30</jats:sub>s especially in predicting both the spectral amplitude and shape of SAs.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"7 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents the results of a research that is part of a larger collaborative effort between the Lawrence Berkeley National Laboratory and the Pacific Earthquake Engineering Research Center, funded by the US Department of Energy Office of Cybersecurity, Energy Security and Emergency Response. The main objective of this study is to assess a suite of near and far-field simulated ground motions obtained from 20 realizations of an M7 Hayward Fault earthquake in the San Francisco Bay Area, California USA, and inform the selection of rupture simulation parameters leading to strong motions. To this aim, comparisons are conducted with NGA-W2 and directivity ground-motion models and a selected population of records. An archetypal steel moment-resisting frame is utilized to assess infrastructure response distributions. The analyses carried out for each simulated event and subdomain with consistent properties in terms of shallow shear-wave velocity proved to be instrumental for better interpreting the differences between simulated motions and empirical models. The main reasons identified for variances between simulations and empirical relationships included (1) directivity effects fully captured by the simulations across the full breadth of rupture models; (2) site vicinity to ruptures that incorporate large-slip patches, particularly if these are in the forward-directivity direction; and (3) presence of geologic structures that can “trap” seismic waves and produce ground motions with large amplitude and long signal duration. The analyses carried out in this work provide a path for interpreting ground-motion site and event specificity obtained from a suite of physics-based simulations, differing only in the rupture model characterization, to inform the selection of simulation scenarios for site-specific engineering analyses under strong excitations. Evidence from this work points to the possibility that current hazard models may underestimate ground-motion intensities in areas where the combined effect of directivity and site conditions results in large ground-motion amplitudes.
{"title":"Ground-motions site and event specificity: Insights from assessing a suite of simulated ground motions in the San Francisco Bay Area","authors":"Floriana Petrone, Arsam Taslimi, Majid Mohammadi Nia, David McCallen, Arben Pitarka","doi":"10.1177/87552930241265132","DOIUrl":"https://doi.org/10.1177/87552930241265132","url":null,"abstract":"This article presents the results of a research that is part of a larger collaborative effort between the Lawrence Berkeley National Laboratory and the Pacific Earthquake Engineering Research Center, funded by the US Department of Energy Office of Cybersecurity, Energy Security and Emergency Response. The main objective of this study is to assess a suite of near and far-field simulated ground motions obtained from 20 realizations of an M7 Hayward Fault earthquake in the San Francisco Bay Area, California USA, and inform the selection of rupture simulation parameters leading to strong motions. To this aim, comparisons are conducted with NGA-W2 and directivity ground-motion models and a selected population of records. An archetypal steel moment-resisting frame is utilized to assess infrastructure response distributions. The analyses carried out for each simulated event and subdomain with consistent properties in terms of shallow shear-wave velocity proved to be instrumental for better interpreting the differences between simulated motions and empirical models. The main reasons identified for variances between simulations and empirical relationships included (1) directivity effects fully captured by the simulations across the full breadth of rupture models; (2) site vicinity to ruptures that incorporate large-slip patches, particularly if these are in the forward-directivity direction; and (3) presence of geologic structures that can “trap” seismic waves and produce ground motions with large amplitude and long signal duration. The analyses carried out in this work provide a path for interpreting ground-motion site and event specificity obtained from a suite of physics-based simulations, differing only in the rupture model characterization, to inform the selection of simulation scenarios for site-specific engineering analyses under strong excitations. Evidence from this work points to the possibility that current hazard models may underestimate ground-motion intensities in areas where the combined effect of directivity and site conditions results in large ground-motion amplitudes.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"1 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1177/87552930241262788
Yvonne Merino, Luis Ceferino, Sebastian Pizarro, Juan C de la Llera
Injured people require hospital emergency services and timely medical treatment after extreme earthquakes. Earthquake-related patients often have trauma injuries and stress-linked (ischemic) ailments that require multiple healthcare procedures, such as minor orthopedic treatment, surgical treatment of fractures, and thrombolysis or thrombectomy. Hospital operation models have been proposed to examine these healthcare procedures; however, they exhibit two fundamental gaps that hinder their ability to assess critical service areas after earthquakes. First, these models rest heavily on emergency procedures based on injury severity rather than type. Second, healthcare demands are often modeled from injury profiles after moderate earthquakes in the United States without including epidemiology data after large earthquakes globally. This approach has led to oversimplified hospital emergency services and resource utilization representation. This research presents a new hospital operations model based on patient injury type and worldwide earthquake epidemiology to fill these gaps. We build the model using discrete-event simulations to capture dynamic metrics on hospital operational outcomes after the earthquake, such as patient time-to-treatment and unassisted patient ratio. We then studied how these metrics vary with different levels of functional capacity in the specific hospital resources. Our results showed that waiting times for emergency department (ED)-level patients vary non-linearly with changes in the number of functional service areas. Also, significant reduction in the waiting time for hospital-level procedures was found for relatively small decrease in the bed occupancy rate, for example, if reverse triage procedures are activated (i.e. a discharge of non-critical patients admitted before the earthquake). Our findings provide a valuable tool for decision-making in hospital preparedness as they explicitly measure the impacts of functional capacity on key healthcare metrics for specific earthquake-related patients.
{"title":"Modeling hospital resources based on global epidemiology after earthquake-related disasters","authors":"Yvonne Merino, Luis Ceferino, Sebastian Pizarro, Juan C de la Llera","doi":"10.1177/87552930241262788","DOIUrl":"https://doi.org/10.1177/87552930241262788","url":null,"abstract":"Injured people require hospital emergency services and timely medical treatment after extreme earthquakes. Earthquake-related patients often have trauma injuries and stress-linked (ischemic) ailments that require multiple healthcare procedures, such as minor orthopedic treatment, surgical treatment of fractures, and thrombolysis or thrombectomy. Hospital operation models have been proposed to examine these healthcare procedures; however, they exhibit two fundamental gaps that hinder their ability to assess critical service areas after earthquakes. First, these models rest heavily on emergency procedures based on injury severity rather than type. Second, healthcare demands are often modeled from injury profiles after moderate earthquakes in the United States without including epidemiology data after large earthquakes globally. This approach has led to oversimplified hospital emergency services and resource utilization representation. This research presents a new hospital operations model based on patient injury type and worldwide earthquake epidemiology to fill these gaps. We build the model using discrete-event simulations to capture dynamic metrics on hospital operational outcomes after the earthquake, such as patient time-to-treatment and unassisted patient ratio. We then studied how these metrics vary with different levels of functional capacity in the specific hospital resources. Our results showed that waiting times for emergency department (ED)-level patients vary non-linearly with changes in the number of functional service areas. Also, significant reduction in the waiting time for hospital-level procedures was found for relatively small decrease in the bed occupancy rate, for example, if reverse triage procedures are activated (i.e. a discharge of non-critical patients admitted before the earthquake). Our findings provide a valuable tool for decision-making in hospital preparedness as they explicitly measure the impacts of functional capacity on key healthcare metrics for specific earthquake-related patients.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"59 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1177/87552930241270562
Christopher A de la Torre, Brendon A Bradley, Robin L Lee, Ayushi Tiwari, Liam M Wotherspoon, Joel N Ridden, Anna E Kaiser
Analysis of prediction–observation residuals from the empirical ground-motion models (GMMs) used in the 2022 New Zealand National Seismic Hazard Model (NZ NSHM) update indicates a general underprediction of ground motions in the period range of [Formula: see text] s for soft sedimentary basin sites in Wellington. This study uses residual analysis to quantify this underprediction, understand the spatial distribution of these residuals and the specific conditions that cause them, and investigate options for the development of non-ergodic site-response adjustments to the GMMs. All 15 GMMs used in the NZ NSHM were evaluated, and the variability in site-response residuals between different models and different tectonic types of earthquake sources was quantified. Sites are regionalized based on different geomorphic features, such as individual basins and valleys. For example, average site terms are calculated for Te Aro, Thorndon, Miramar, Lower Hutt, Upper Hutt, and several smaller valleys. The period at which maximum underprediction occurs at these sedimentary basin and valley sites was found to correlate well with the fundamental site period of the soil profile [Formula: see text], suggesting improvements can be made to regionalized GMMs by incorporating site period into the site-response prediction for sedimentary basin sites.
{"title":"Analysis of site-response residuals from empirical ground-motion models to account for observed sedimentary basin effects in Wellington, New Zealand","authors":"Christopher A de la Torre, Brendon A Bradley, Robin L Lee, Ayushi Tiwari, Liam M Wotherspoon, Joel N Ridden, Anna E Kaiser","doi":"10.1177/87552930241270562","DOIUrl":"https://doi.org/10.1177/87552930241270562","url":null,"abstract":"Analysis of prediction–observation residuals from the empirical ground-motion models (GMMs) used in the 2022 New Zealand National Seismic Hazard Model (NZ NSHM) update indicates a general underprediction of ground motions in the period range of [Formula: see text] s for soft sedimentary basin sites in Wellington. This study uses residual analysis to quantify this underprediction, understand the spatial distribution of these residuals and the specific conditions that cause them, and investigate options for the development of non-ergodic site-response adjustments to the GMMs. All 15 GMMs used in the NZ NSHM were evaluated, and the variability in site-response residuals between different models and different tectonic types of earthquake sources was quantified. Sites are regionalized based on different geomorphic features, such as individual basins and valleys. For example, average site terms are calculated for Te Aro, Thorndon, Miramar, Lower Hutt, Upper Hutt, and several smaller valleys. The period at which maximum underprediction occurs at these sedimentary basin and valley sites was found to correlate well with the fundamental site period of the soil profile [Formula: see text], suggesting improvements can be made to regionalized GMMs by incorporating site period into the site-response prediction for sedimentary basin sites.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"42 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1177/87552930241266741
Peter M Powers, Jason M Altekruse, Andrea L Llenos, Andy J Michael, Kirstie L Haynie, Peter J Haeussler, Adrian M Bender, Sanaz Rezaeian, Morgan P Moschetti, James A Smith, Richard W Briggs, Robert C Witter, Charles S Mueller, Yuehua Zeng, Demi L Girot, Julie A Herrick, Allison M Shumway, Mark D Petersen
US Geological Survey (USGS) National Seismic Hazard Models (NSHMs) are used extensively for seismic design regulations in the United States and earthquake scenario development, as well as risk assessment and mitigation for both buildings and infrastructure. This 2023 update of the long-term, time-independent Alaska NSHM includes substantial changes to both the earthquake rupture forecast (ERF) and ground motion models (GMMs). The ERF includes numerous additions to the finite-fault model, considers two deformation models, and introduces updated declustering and smoothing algorithms in the gridded background seismicity model. For the Alaska–Aleutian subduction zone, megathrust earthquakes occur on an updated structural and segmentation model, and the moment magnitude (M) 8+ rupture and rate model include a logic tree branch that considers slip rates derived from geodetic models of interface coupling. The megathrust model considers multiple models of down-dip width, and magnitudes are computed using newly developed scaling relations. For subduction intraslab events and subduction interface events with M < 7, the 2023 update uses a smoothed seismicity model with rupture depths derived from Slab2. The 2023 model updates GMMs in all tectonic settings using the recently published Next Generation Attenuation Subduction (NGA-Sub) GMMs for subduction interface and intraslab events, and the NGA-West2 GMMs for active crustal settings. Collectively, additions and updates to the Alaska NSHM result in hazard increases across most of south-central Alaska relative to the previous model, published in 2007. These changes are primarily due to the adoption of updated rate models for the large-magnitude interface events and the NGA-Sub GMMs that have much higher aleatory variability (sigma), consistent with global observations, and that include models of epistemic uncertainty.
{"title":"The 2023 Alaska National Seismic Hazard Model","authors":"Peter M Powers, Jason M Altekruse, Andrea L Llenos, Andy J Michael, Kirstie L Haynie, Peter J Haeussler, Adrian M Bender, Sanaz Rezaeian, Morgan P Moschetti, James A Smith, Richard W Briggs, Robert C Witter, Charles S Mueller, Yuehua Zeng, Demi L Girot, Julie A Herrick, Allison M Shumway, Mark D Petersen","doi":"10.1177/87552930241266741","DOIUrl":"https://doi.org/10.1177/87552930241266741","url":null,"abstract":"US Geological Survey (USGS) National Seismic Hazard Models (NSHMs) are used extensively for seismic design regulations in the United States and earthquake scenario development, as well as risk assessment and mitigation for both buildings and infrastructure. This 2023 update of the long-term, time-independent Alaska NSHM includes substantial changes to both the earthquake rupture forecast (ERF) and ground motion models (GMMs). The ERF includes numerous additions to the finite-fault model, considers two deformation models, and introduces updated declustering and smoothing algorithms in the gridded background seismicity model. For the Alaska–Aleutian subduction zone, megathrust earthquakes occur on an updated structural and segmentation model, and the moment magnitude (M) 8+ rupture and rate model include a logic tree branch that considers slip rates derived from geodetic models of interface coupling. The megathrust model considers multiple models of down-dip width, and magnitudes are computed using newly developed scaling relations. For subduction intraslab events and subduction interface events with M < 7, the 2023 update uses a smoothed seismicity model with rupture depths derived from Slab2. The 2023 model updates GMMs in all tectonic settings using the recently published Next Generation Attenuation Subduction (NGA-Sub) GMMs for subduction interface and intraslab events, and the NGA-West2 GMMs for active crustal settings. Collectively, additions and updates to the Alaska NSHM result in hazard increases across most of south-central Alaska relative to the previous model, published in 2007. These changes are primarily due to the adoption of updated rate models for the large-magnitude interface events and the NGA-Sub GMMs that have much higher aleatory variability (sigma), consistent with global observations, and that include models of epistemic uncertainty.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"9 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1177/87552930241262775
Arsam Taslimi, Floriana Petrone
This study investigates the vulnerability of long-span suspension bridges to spatially variable vertical ground motions (SV-VGMs). While of recognized importance, a comprehensive understanding of this topic has been traditionally limited by the unavailability of an adequate number of arrays of motions. In this work, 10 simulations of a large-magnitude Hayward Fault earthquake are utilized to perform site-specific structural response assessments of a suspension bridge under different load scenarios. A detailed nonlinear model representative of the West San Francisco-Oakland Bay Bridge is employed as the case study structure. Four sets of nonlinear time-history analyses are performed with and without VGMs and with and without the incorporation of spatial variability to offer the basis for a complete comparison of the demand distributions across different load cases. Results indicate that VGMs largely influence the response of the bridge decks in the vertical direction, with an increase in drifts up to 2× for the case of synchronous input and up to 2.5× for the case of asynchronous inputs. The analysis of the bridge response in the time and frequency domain across all load cases reveals a high sensitivity of the decks’ response to minor time lags in input motions of comparable amplitude, which are seen to activate the contribution of higher modes to the structural response. Evidence from this study points to the potential of severely underestimating structural demands if the (even limited) spatial variability of the input motions is not incorporated correctly. For the case study structure, the probability of exceeding the onset of nonlinearity in the short decks at the design earthquake level is seen to increase by a factor of about two when considering SV-VGMs as opposed to synchronous horizontal motions only.
{"title":"Vulnerability of suspension bridges to spatially variable vertical ground motions","authors":"Arsam Taslimi, Floriana Petrone","doi":"10.1177/87552930241262775","DOIUrl":"https://doi.org/10.1177/87552930241262775","url":null,"abstract":"This study investigates the vulnerability of long-span suspension bridges to spatially variable vertical ground motions (SV-VGMs). While of recognized importance, a comprehensive understanding of this topic has been traditionally limited by the unavailability of an adequate number of arrays of motions. In this work, 10 simulations of a large-magnitude Hayward Fault earthquake are utilized to perform site-specific structural response assessments of a suspension bridge under different load scenarios. A detailed nonlinear model representative of the West San Francisco-Oakland Bay Bridge is employed as the case study structure. Four sets of nonlinear time-history analyses are performed with and without VGMs and with and without the incorporation of spatial variability to offer the basis for a complete comparison of the demand distributions across different load cases. Results indicate that VGMs largely influence the response of the bridge decks in the vertical direction, with an increase in drifts up to 2× for the case of synchronous input and up to 2.5× for the case of asynchronous inputs. The analysis of the bridge response in the time and frequency domain across all load cases reveals a high sensitivity of the decks’ response to minor time lags in input motions of comparable amplitude, which are seen to activate the contribution of higher modes to the structural response. Evidence from this study points to the potential of severely underestimating structural demands if the (even limited) spatial variability of the input motions is not incorporated correctly. For the case study structure, the probability of exceeding the onset of nonlinearity in the short decks at the design earthquake level is seen to increase by a factor of about two when considering SV-VGMs as opposed to synchronous horizontal motions only.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"21 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1177/87552930241263618
Kendra Johnson, Thomas Chartier, Marco Pagani, Yesica Perez, Vladimir Guzmán, Maria Betania Roque de Medina, Richard Styron, Catalina Yepes-Estrada
The Dominican Republic experiences moderate to high seismic hazard mostly caused by oblique convergence at the Caribbean/North American plate boundary that manifests as subduction zones, less-pronounced subduction-like trenches with thrust faulting, long strike-slip faults parallel to the plate boundary, and onshore deformation. Historical earthquakes have damaged the Dominican Republic’s large cities and those in neighboring Haiti, once requiring relocation. Given this, the Dominican Republic joined the “Training and Communication for Earthquake Risk Assessment” (TREQ) project funded by the United States Agency for International Development, which aimed to increase earthquake risk assessment capacity in Latin American cities. The TREQ project was the basis for developing an openly available probabilistic seismic hazard model for the Dominican Republic. The input model was developed from two main datasets: a homogenized earthquake catalog and an active faults database that combines results of recent local projects with a global database. The seismic source characterization used these to constrain source geometries and occurrence rates for active shallow crustal earthquakes, subduction interfaces and subduction-like thrusts, and intraslab earthquakes. Shallow crustal earthquakes, including those on subduction-like thrusts, are modeled by smoothed seismicity and fault sources, the latter using pre-defined geometries that permit multi-fault ruptures. Seismicity on the Puerto Rico Trench subduction interface is modeled as a fault source, while intraslab sources use pre-defined gridded ruptures inside the intraslab volume. The source characterization applies epistemic uncertainties to modeling assumptions affecting occurrence rates and maximum magnitudes. The ground motion characterization used residual analyses from past regional projects as a basis, updating some components with more recent ground motion models. Computed hazard results reinforce those from recent studies in terms of geographical hazard patterns and levels. For 475-year return periods, peak ground acceleration (PGA) in Santiago de los Caballeros reaches 0.50 g, controlled by the Septentrional Fault, while all tectonic region types contribute to the PGA 0.31 g computed for Santo Domingo.
{"title":"Probabilistic seismic hazard analysis for the Dominican Republic","authors":"Kendra Johnson, Thomas Chartier, Marco Pagani, Yesica Perez, Vladimir Guzmán, Maria Betania Roque de Medina, Richard Styron, Catalina Yepes-Estrada","doi":"10.1177/87552930241263618","DOIUrl":"https://doi.org/10.1177/87552930241263618","url":null,"abstract":"The Dominican Republic experiences moderate to high seismic hazard mostly caused by oblique convergence at the Caribbean/North American plate boundary that manifests as subduction zones, less-pronounced subduction-like trenches with thrust faulting, long strike-slip faults parallel to the plate boundary, and onshore deformation. Historical earthquakes have damaged the Dominican Republic’s large cities and those in neighboring Haiti, once requiring relocation. Given this, the Dominican Republic joined the “Training and Communication for Earthquake Risk Assessment” (TREQ) project funded by the United States Agency for International Development, which aimed to increase earthquake risk assessment capacity in Latin American cities. The TREQ project was the basis for developing an openly available probabilistic seismic hazard model for the Dominican Republic. The input model was developed from two main datasets: a homogenized earthquake catalog and an active faults database that combines results of recent local projects with a global database. The seismic source characterization used these to constrain source geometries and occurrence rates for active shallow crustal earthquakes, subduction interfaces and subduction-like thrusts, and intraslab earthquakes. Shallow crustal earthquakes, including those on subduction-like thrusts, are modeled by smoothed seismicity and fault sources, the latter using pre-defined geometries that permit multi-fault ruptures. Seismicity on the Puerto Rico Trench subduction interface is modeled as a fault source, while intraslab sources use pre-defined gridded ruptures inside the intraslab volume. The source characterization applies epistemic uncertainties to modeling assumptions affecting occurrence rates and maximum magnitudes. The ground motion characterization used residual analyses from past regional projects as a basis, updating some components with more recent ground motion models. Computed hazard results reinforce those from recent studies in terms of geographical hazard patterns and levels. For 475-year return periods, peak ground acceleration (PGA) in Santiago de los Caballeros reaches 0.50 g, controlled by the Septentrional Fault, while all tectonic region types contribute to the PGA 0.31 g computed for Santo Domingo.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"39 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1177/87552930241262753
Egemen Sönmez, Mario E Rodriguez
The February 2023 earthquakes in Türkiye caused widespread devastation and fatalities, highlighting the critical contrast in the seismic performance of reinforced concrete (RC) buildings with moment-resistant frames and those with structural walls. This study employs analyses of nonlinear single-degree-of-freedom (SDOF) systems using selected accelerograms from the earthquakes to evaluate the behavior of these structural systems. Three SDOF systems representing flexible and stiffer frame buildings, alongside RC wall buildings, were examined. The results highlighted the susceptibility of frame buildings to severe damage and collapse compared with the excellent performance of RC wall buildings. Moreover, the study emphasizes a shift of design focus from life safety to functional recovery. It also identifies potential scenarios regarding consecutive earthquake effects. Overall, the findings advocate adequately designed RC wall buildings for enhanced seismic performance and immediate occupation following major earthquakes.
{"title":"Frame buildings are not an answer for earthquakes: The case of the February 2023 earthquakes in Türkiye","authors":"Egemen Sönmez, Mario E Rodriguez","doi":"10.1177/87552930241262753","DOIUrl":"https://doi.org/10.1177/87552930241262753","url":null,"abstract":"The February 2023 earthquakes in Türkiye caused widespread devastation and fatalities, highlighting the critical contrast in the seismic performance of reinforced concrete (RC) buildings with moment-resistant frames and those with structural walls. This study employs analyses of nonlinear single-degree-of-freedom (SDOF) systems using selected accelerograms from the earthquakes to evaluate the behavior of these structural systems. Three SDOF systems representing flexible and stiffer frame buildings, alongside RC wall buildings, were examined. The results highlighted the susceptibility of frame buildings to severe damage and collapse compared with the excellent performance of RC wall buildings. Moreover, the study emphasizes a shift of design focus from life safety to functional recovery. It also identifies potential scenarios regarding consecutive earthquake effects. Overall, the findings advocate adequately designed RC wall buildings for enhanced seismic performance and immediate occupation following major earthquakes.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"52 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1177/87552930241266742
Jeannette Sutton, Savanah Crouch, Nicholas Waugh, Michele M Wood
Ridgecrest, CA, experienced the Searles Valley earthquake sequence in 2019 and a “false” earthquake alert in 2020, providing a unique opportunity to examine the effects of earthquake experience on future responses to informational cues to action (i.e., earthquake alert), as well as reactions to a “false” alert. We conducted in-depth interviews with 41 residents using the protective action decision-making model as a theoretical framework. Interviewees reported a variety of environmental cues that signaled the onset of an earthquake, including sensing a foreshock, hearing the earth rumble, hearing objects fall to the floor and break, and observing unusual animal behavior. Fewer individuals received social cues to action. More individuals reported performing “drop, cover, and hold on,” and fewer reported standing in a doorway in response to the 2020 alert than had done so in the prior 2019 earthquake. Several respondents reported maintaining protective actions well after the “false” alert was issued, and many waited more than 5 min before determining there was no threat present. Prior experience of the 2019 earthquake series affected perceptions of the earthquake alert and what actions to take; however, there was limited knowledge of how the ShakeAlert system worked to monitor, detect, and model earthquakes via earthquake early warning to persons at risk. Findings indicate there is a need for additional public education about ShakeAlert-powered earthquake early warning, including how far in advance one can expect to receive an alert, as well as the protective actions one should take and when to take them.
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