Ground Motion Intensity Research Articles

Reducing the uncertainties in the NGA-West2 ground motion models by incorporating the frequency and amplitude of the fundamental peak of the horizontal-to-vertical spectral ratio of surface ground motions

Ground motion models (GMMs) are developed empirically to predict ground motion intensity measures. The site effects in GMMs are usually addressed using time-averaged shear-wave velocity for the upper 30 m of the site (VS30) and shear-wave isosurface depth (i.e. Z1.0 and Z2.5). However, the former does not include the effect of layered soil structure on the site’s response, and the latter is generally inferred. Many studies have shown that site fundamental frequency can be used as an additional site proxy. Using horizontal-to-vertical spectral ratio (HVSR), one can estimate the site fundamental frequency in a fast and inexpensive way. In this article, a model is developed to incorporate site fundamental frequency and its corresponding amplification factor in the Next Generation Attenuation (NGA)-West2 GMMs to reduce the uncertainties. First, a subset of the NGA-West2 database consisting of 14,636 recordings from 298 events is selected after a two-step screening procedure and used to compute the horizontal-to-vertical response spectral ratio (HVSRPSA) of recorded surface ground motions. Second, automated methodologies previously developed by the authors are used to obtain maximum likelihood estimates of site fundamental frequency (fml), its corresponding amplitude (Aml), and associated uncertainties. Third, a mixed-effect maximum likelihood approach is implemented for residual analysis and site-term residual calculation. Finally, an HVSR-based model is developed for the NGA-West2 dataset considering the relationship between site-term residual and the HVSR-based proxies (i.e. fml and Aml). In this model, Aml is as important as fml in reducing the uncertainties. Results show that using a single HVSR-based model can consistently reduce the site-to-site variability ([Formula: see text]) for all NGA-West2 GMMs, which already include the effect of VS30, Z1.0, or Z2.5. Besides, the reduction in [Formula: see text] is period-dependent, with an average of 13% reduction. As a result of the reduction in [Formula: see text], total standard deviation ( σ) decreases by 3.5% on average.

Probabilistic urban cascading multi-hazard risk assessment methodology for ground shaking and post-earthquake fires

A probabilistic methodology is presented for assessing cascading multi-hazard risk for ground shaking and post-earthquake fires at a regional scale. The proposed methodology focuses on direct economic losses to buildings caused by the combined effect of ground shaking and post-earthquake fires and evaluates the exceedance probability of the regional shaking–fire losses in a predefined future time period by comprehensively considering the effects of various uncertain factors on the losses via Monte Carlo simulations. Probabilistic seismic risk assessments are extended by integrating post-earthquake fire models with seismic activity models, ground motion prediction equations, and seismic fragility functions. The fire models include post-earthquake ignition models, a weather model, a physics-based urban fire spread model, and a fire brigade response model. This integrated modeling enables the incorporation of the following uncertain factors with causal relationships into the assessments: earthquake occurrence, ground motion intensity distribution, damage to buildings resulting from ground shaking, post-earthquake ignition occurrence and occupant firefighting, weather condition, fire brigade response time including time to detection, and damage to buildings resulting from post-earthquake urban fire spread. To demonstrate the methodology, a realistic case study is conducted for a historical urban area with closely spaced wooden buildings in Kyoto, Japan, focusing on possible large earthquakes along major active faults. Contrary to conventional single-hazard approaches, the results highlight the impact of multi-hazard consideration on risk assessments. This indicates that the methodology can be a useful tool for more appropriately understanding earthquake risk and promoting risk-informed decision-making in urban communities for risk reduction.

Exceedance of design seismic actions during the 2016-2017 central Italy seismic sequence: sensitivity to two seismic hazard models

In Italy, seismic ground motion intensity for structural design relies on probabilistic seismic hazard analysis (PSHA). Research has shown that, even in the case of a moderate magnitude earthquake, it is expected that ground motion intensities larger than the design counterparts are observed at some sites in the epicentral region. The area where such an exceedance has possibly occurred can be assessed via ShakeMap. In the case of seismic sequences, ShakeMap envelopes allow to identify the fraction of the region of interest subjected to at least one exceedance of design seismic actions. For the 2016-2017 central Italy sequence, ShakeMap envelopes reveal that exceedance of the design intensity enforced by the current building code occurred in an area covering thousands of square kilometers, depending on the spectral and exceedance return period of the design intensity. This study quantifies the exceedance area of ground motion intensity according to the PSHA results based on two alternative PSHA models for Italy. One is that at the basis of the official PSHA for Italy adopted by the current building code, known as MPS04; the other relies on a grid-seismicity source model deriving from a set of source models recently developed for a new PSHA study for the country (MPS19). Looking at ShakeMap envelopes, it is found that the estimated exceedance area is of the same order of magnitude for the two hazard models, at least for the spectral and exceedance return periods considered herein.

Fragility models for RC frames with masonry infills and analysis of the efficiency of different IMs

The Italian territory is historically known as a seismic zone, but insufficient attention to seismic design in the past years has led to a high vulnerability of the existing building stock. Fragility models have become important tools for assessing the seismic vulnerability of existing buildings. This work aims to contribute to the assessment of fragility models for reinforced concrete (RC) frames with masonry infills. Based on an analysis of census data on existing buildings and on AeDES forms following the 2012 earthquake in Emilia, a representative 4-storey RC building was defined and modelled with finite elements. A concentrated plasticity approach has been adopted and infill panels have been schematized through an equivalent strut model. Structural capacity has been determined conducting a series of pushover analysis, considering the uncertainties in the mechanical characteristics by means of a Latin Hypercube Sampling. Displacement demand has been evaluated through a multi-stripe non-linear dynamic analysis on the equivalent single degree of freedom systems, by using a set of recorded accelerograms. Fragility curves have been evaluated by means of a regression model on the exceedance of each damage state, defined according to the EMS-98 scale. Particular attention was given to comparing the efficiency of various ground motion Intensity Measures (IMs) in correlating with displacement demand and in describing damage evolution in the building.

Observed damage and empirical predictive model of the school building heritage of the Marche region

The 2016 seismic sequence that struck Central Italy, with its three mainshocks and numerous aftershocks, caused widespread damages to building heritage. Among the buildings that suffered damages, schools are considered relevant structures from multiple points of view. Educational institutes, indeed, host children and young people during their training years in facilities that are often old and realized without recent safety Standards becoming, therefore, non-resilient, nor robust structures towards multiple natural hazards. In this paper, a database containing information regarding the geolocation of individual buildings, no. of floors, the floor surface, the construction period, the structural type and the potential presence of landscape or hydrogeological constraints, has been realized with reference to the schools of the Marche region, by merging different sources of information. In addition, the database also collects information regarding observed damages and recorded seismic intensities to schools during the 2016 Central Italy earthquake.Once built up the database, an empirical predictive model, known in literature and already used for the evaluation of potential post-earthquake scenarios to cultural heritage, is applied to school buildings located into the seismic crater of the Marche region, by estimating the parameters of the model through inference techniques. The probabilistic model applied, relates a measure of the ground motion intensity to an overall damage index, continuous in the range [0,1]. Moreover, if one integrates the partial information related to damaged buildings often provided by the post-earthquake surveys, with the data related to the undamaged and/or collapsed structures, the model can provide a full risk assessment procedure. Finally, fragility curves are also derived, to make it possible the use of the research outcomes in risk frameworks based on a discrete description of the consequences.

Ground Motion Analysis Toolbox and Seismic Scenarios Toolbox: software tools for seismic damage scenarios assessment in the Emilia-Romagna Region

After an earthquake, it is essential to have estimates of the potential destructiveness of ground motions and predictions of damage scenarios. These rely on the knowledge of specific features of the potentially affected area, both in terms of intrinsic characteristics (e.g. morphology, near surface geology, etc.) and elements at risk (e.g. building typologies, population distribution, etc.). Within this context, this paper describes a series of software tools developed that allow to analyze recorded accelerograms, create shake maps in terms of different ground motion intensity measures, and estimate damage scenarios. In particular, ground-motion recordings from the Italian National Accelerometric Network are processed to compute a number of ground motion Intensity Measures (IMs), while acceleration spectra are used to compare displacement demands for a series of equivalent single degree of freedom systems, derived from pushover analyses on a series of representative buildings, by using simplified methods (e.g. N2, CSM, IN2, etc.). The IMs calculated from the recordings at the various stations are used, together with attenuation and spatial correlation models, to obtain shake maps, using different criteria for quantifying site effects. These maps are used together with regional census data and various fragility models to estimate damage scenarios, using a Monte Carlo simulation approach.

Seismic retrofit of reinforced concrete frames by direct loss-based design

This paper introduces a procedure for the retrofit design of reinforced concrete (RC) frame buildings to achieve the desired target level of earthquake-induced loss for a given seismic hazard profile. The methodology is “direct” because the loss target is specified in the first step of the procedure, and, in principle, no design iterations are required. The target loss level is defined based on designer/client preferences and/or external constraints (e.g., foundation capacity). The proposed procedure relies on a simplified loss assessment enabled by a surrogate model defining the probability distribution of the seismic deformation demands of single degree of freedom (SDoF) systems given different ground-motion intensity levels. Combined with a hazard curve and a building-level damage-to-loss model, such a surrogate model is used to map candidate SDoF force-displacement curves to their earthquake-induced loss by assuming a given retrofit strategy. In this case, the considered retrofit strategy involves changing the frame's local hierarchy of strength to ensure a global plastic structure mechanism. Under such assumptions, a designer can select a design force-displacement curve among those that comply with the chosen loss target. The detailing of the retrofitted frame is carried out according to the direct displacement-based design principles and the Simplified Lateral Mechanism Analysis (SLaMA). The procedure is applied to an under-designed RC frame building retrofitted with concrete jacketing. A benchmark loss estimate is calculated using non-linear time-history analyses for loss assessment purposes. The proposed procedure shows satisfactory compliance with the benchmark loss, emphasising the procedure's effectiveness in practice.

Predictive models for the run-out distance of clay slopes based on material point method

This paper aims to propose run-out distance predictive models for clay slopes using the material point method (MPM), which can simulate the progressive failure process of slopes considering the strain softening effect of soils. A suite of 100 ground motions is selected from the NGA-West2 database and then scaled for conducting the dynamic analysis of slopes. The permanent slope displacements (D) can be classified into two categories, namely the “un-failure” category with D smaller than 0.4 m and the “failure” category with D in the range of 10 m to 15 m. It is found that peak ground velocity (PGV) exhibits the highest correlation with D for the “un-failure” category, whereas all ground-motion intensity measures (e.g., PGV, peak ground acceleration) are less correlated with D for the “failure” category. Therefore, the run-out distance of collapsed clay slopes is more related to the failure model rather than the triggering shaking intensities. Moreover, thousands of slope models with various slope angles, slope heights (H), soil densities, and peak and residual strength parameters are developed based on MPM. The run-out distances for the slopes being collapsed are then collected. Predictive models for different slope angles are proposed, which predict the run-out distance as a function of H, unit weight, residual cohesion, and residual friction angle. The proposed models are applicable for clay slopes with slope angles in the range of 30° to 45° and H in the range of 10 m to 30 m.

Gaussian process regression-based surrogate modelling for direct loss-based seismic design of low-rise base-isolated structures

Seismic base isolation has gained popularity in the last decades. As a result, many structures are now equipped with base isolation systems to offer enhanced seismic performance and meet the needs of risk-aware stakeholders. However, a robust performance-based seismic design of these types of structures is generally not carried out due to the iterative nature of common design approaches and the time/computational resources required for such iterations, which are incompatible with the preliminary design phase. Indeed, seismic risk/loss is often just assessed at the end of the design process as a final verification step. This paper offers an overview of a simplified methodology for the seismic design of low-rise structures equipped with a base isolation system to achieve a predefined level of earthquake-induced economic loss while complying with a predefined minimum level of structural reliability. The main advantage of the proposed methodology is that it requires no design iterations. The procedure is enabled by Gaussian-process-regression-based surrogate probabilistic seismic demand modelling of equivalent single degree of freedom systems (i.e., the probability distribution of peak horizontal displacements and accelerations on top of the isolation layer conditional on different ground-motion intensity levels). Combined with simplified loss models for the base isolation system and the structural and non-structural components of the superstructure, this approach allows mapping a range of structural configurations to their resulting seismic loss. A designer can then select one of the identified combinations of the strength of the superstructure and properties of the isolation system conforming with the loss target, and reliability requirements, and consequently detail the superstructure and isolation system accordingly. This paper introduces the implemented surrogate probabilistic seismic demand models and provides an overview of a tentative Direct Loss-based Design procedure for low-rise base-isolated structures.

The Over-Prediction of Seismically Induced Soil Liquefaction during the 2016 Kumamoto, Japan Earthquake Sequence

Following the M7.0 strike-slip earthquake near Kumamoto, Japan, in April of 2016, most geotechnical engineering experts believed that there would be significant soil liquefaction and liquefaction-induced infrastructure damage observed in the densely populated city of Kumamoto during the post-event engineering reconnaissance. This belief was driven by several factors including the young geologic environment, alluvially deposited soils, a predominance of loose sandy soils documented in publicly available boring logs throughout the region, and the high intensity ground motions observed from the earthquake. To the surprise of many of the researchers, soil liquefaction occurred both less frequently and less severely than expected. This paper summarizes findings from our field, laboratory, and simplified analytical studies common to engineering practice to assess the lower occurrence of liquefaction. Measured in situ SPT and CPT resistance values were evaluated with current liquefaction triggering procedures. Minimally disturbed samples were subjected to cyclic triaxial testing. Furthermore, an extensive literature review on Kumamoto volcanic soils was performed. Our findings suggest that current liquefaction triggering procedures over-predict liquefaction frequency and effects in alluvially deposited volcanic soils. Volcanic soils were found to possess properties of soil crushability, high fines content, moderate plasticity, and unanticipated organic constituents. Cyclic triaxial tests confirm the high liquefaction resistance of these soils. Moving forward, geotechnical engineers should holistically consider the soil’s mineralogy and geology before relying solely on simplified liquefaction triggering procedures when evaluating volcanic soils for liquefaction.

Seismic Fragility of Aging Elevated Water Tank with Smooth Bars Considering Soil Structure Interaction

The functionality of elevated water tanks is pivotal to assure after an earthquake as water supply is expected to be uninterrupted. Although elevated water tanks with deformed bars are widely studied, limited works exist for water tanks with smooth bars, although such tanks comprise a considerable fraction, even in the high seismic regions. To quantify the seismic vulnerability of aging elevated water tanks with smooth bars, we created analytical fragility functions for full, half, and empty reservoir conditions, considering fluid–structure and soil–structure interactions. The sum of findings reflects that soil flexibility and the amount of water present in the tank have a significant effect on overall seismic fragility, especially at higher damage states. The tanks are found to be most vulnerable when they are fully filled with water. The effect of soil flexibility is more pronounced at higher damage states. The difference between the fragility of flexible base and fixed base structures is found to increase with increasing ground motion intensity and it is the highest for the empty tank condition.

A Real-Time and Data-Driven Ground-Motion Prediction Framework for Earthquake Early Warning

ABSTRACTThe ShakeAlert earthquake early warning system in the western United States characterizes earthquake source locations and magnitudes in real time, issuing public alerts for areas where predicted ground-motion intensities exceed a threshold value. Although rapid source characterization methods have attracted significant scientific attention in recent years, the ground-motion models used by ShakeAlert have received notably less. This study develops a data-driven framework for earthquake early warning-specific ground-motion models by precomputing and incorporating site-specific corrections, while using a Bayesian approach to estimate event-specific corrections in real time. The study involves analyzing a quality-controlled set of more than 420,000 seismic recordings from 1389 M 3–7 events in the state of California, from 2011 to 2022. We first compare the observed ground motions to predictions from existing ground-motion models, namely the modified Boore and Atkinson (2008) and active crustal Next Generation Attenuation (NGA)-West2 ground-motion prediction equations, before implementing a new Bayesian model optimized for a real-time setting. Residual analysis of peak ground acceleration and peak ground velocity metrics across a host of earthquake rupture scenarios from the two ground-motion models show that the active crustal NGA-West2 model is better suited for ShakeAlert in California. In addition, the event-terms calculated using our Bayesian approach rapidly converge such that errors from earthquake magnitude estimation can be corrected for when forecasting shaking intensity in real time. Equipped with these improved ground-shaking predictions, we show that refined ShakeAlert warnings could be issued to the public within as soon as 5 s following ShakeAlert’s initial warning. This approach could be used both to reduce prediction uncertainties and thus improve ShakeAlert’s alerting decision.

Probabilistic prediction of ground-motion intensity for regions lacking strong ground-motion records

Probabilistic prediction of ground-motion intensity in regions lacking strong ground-motion records is a vital issue for seismic structural design. Several approaches have been suggested for this purpose, and nearly all of them directly import and adjust the ground-motion prediction equation (GMPE) of ground-motion measures such as the peak ground acceleration (PGA) or spectral acceleration (SA) from data-rich regions. However, as the transmissions of PGA and SA from the source to the site correspond to nonlinear processes, this import and adjustment may lead to an unrealistic evaluation of ground motion. In this study, a novel probabilistic prediction method of ground-motion intensity for such regions is proposed. In contrast to the current approach wherein the GMPE of ground-motion measures such as PGA or SA is directly used, a Fourier amplitude spectral (FAS) model is suggested to express the seismic transmission process from the source to the site. The ground-motion intensities of PGA or SA are obtained from the FAS model using the random vibration theory. The exceedance probability of ground-motion intensity is calculated based on Monte Carlo simulations. As the FAS conforms to the linear system theory and the determination of FAS model does not require too many ground-motion records, the proposed method should be convenient for the probabilistic prediction of ground-motion intensity in regions lacking strong ground-motion records.

Improving soil liquefaction prediction through an extensive database and innovative ground motion characterization: A case study of Port Island liquefied site

Liquefaction is a phenomenon in which soils lose their strength and stiffness significantly during earthquake shakings. It is very important to accurately predict the liquefaction triggering and permanent displacement of liquefied sites under different seismic conditions. This study systematically investigates the effect of ground motion characteristics on the evolution of important physical quantities during the liquefaction process, while the relative capacity of various ground motion intensity measures (IMs) in predicting the pore-pressure generation and the permanent deformation in liquefiable soils are studied. An extensive database containing 501 three-component ground motion records is established to improve soil liquefaction prediction under different earthquake scenarios. A significant number of fully nonlinear dynamic analyses are performed for the Port Island liquefied site, where advanced constitutive models are used to realistically characterize the nonlinear soil behaviors. Results from numerical simulations demonstrate that the energy-related IMs such as CAV5 have a superior predictive capacity than the peak ground acceleration in predicting the liquefaction initiation and permanent displacement, but the predictions based on scalar IMs are not sufficient because residuals are strongly depended on earthquake magnitude and rupture distance. On the other hand, vector IMs that incorporate both energy and peak value characteristics of ground motions can improve the predictive capabilities regarding pore pressure generation and permanent deformation in liquefiable soils. The study helps lay down the basis towards an improved procedure for liquefaction hazard evaluation and mitigation.

On the choice of ground motion intensity measure and the number of records for cloud analysis-based seismic demand assessment

Cloud analysis has emerged as a popular tool for the seismic demand/fragility assessment of structures. The output of cloud analysis is a seismic demand model which relates an Engineering Demand Parameter (EDP) indicative of structural distress to an Intensity Measure (IM) signifying the severity of ground shaking. IMs commonly used for probabilistic seismic demand assessment are quite heterogenous with respect to their “efficiency”, i.e. their degree of correlation with a specific EDP. This feature has serious implications on the number of ground motion records that must be used to perform cloud analysis on a given structure in order to accurately describe the distribution of the EDP at various IM levels. In the current study, demand models for maximum interstorey drift (?max), based on a wide spectrum of IMs, are developed from the cloud analyses of a five-storey RC bare frame structure using a suite of fifty unscaled natural ground motion records. The method of bootstrap resampling is used to investigate the convergence of the regression coefficients in the demand model with the size of the bootstrap subsamples, each comprising of a limited subset of records drawn from the original suite with repetitions allowed. This procedure helps determine the minimum number of ground motion records necessary for the calibration of demand models without compromising its accuracy in predicting the drift demands. Results from the study indicate a strong correlation between the efficiency of various IMs and the optimal number of records required to produce reliable seismic demand models.

Non-linear Dynamic Analysis of RC Structures Under Earthquake Sequences

Earthquakes in active seismic regions usually occur in a series of medium to strong intensity ground motions at small intervals of times. A large intensity mainshock (MS) is often followed by a series of aftershocks (AS) or even preceded by smaller foreshocks. This sequence type of mainshock-aftershock (MS-AS) ground motions with varying intensity pose major seismic hazard as there is limited scope of repair and retrofitting between seismic events. Due to continuous and repeated seismic ground motions over a brief period of time, the damages in the structure gets accumulated and structure collapse. This study navigates the behaviour of reinforced concrete structures under such seismic sequences. For this purpose, the nonlinear response of three 12 storey reinforced concrete buildings (regular plan, mass irregularity and diaphragm irregularity) is evaluated. The buildings are subjected to five real seismic sequences from previous earthquakes. Nonlinear dynamic analyses are carried out to study the response of buildings under MS and MS-AS sequences considering: a) material and geometric non linearities and b) irregularities. A single highest aftershock is considered in the present study. The results in this study indicates that MS-AS seismic sequence considering both material and geometric nonlinearities has significant effect on the response of structure. It also showed that seismic sequences significantly alter the response of irregular structure.

Large‐scale ground motion simulation of the 2016 Kumamoto earthquake incorporating soil nonlinearity and topographic effects

AbstractA large‐scale physics‐based simulation is conducted to investigate ground motion distribution in the Mw 7.0 2016 Kumamoto earthquake, Japan. The model simulates the earthquake scenario from fault rupture to wave propagation, and localized site response with consideration of the combined effect of soil nonlinearity and topographic amplification. The simulation domain is 51 km × 43 km × 25 km, and the obtained ground motion time histories are compared satisfactorily with recordings from KiK‐net and K‐NET. Ground motion distribution considering nonlinear soil response and topographic amplification is presented. A 3D equivalent linear model is developed to mimic the soil nonlinearity, and it is demonstrated that neglecting soil nonlinearity could over‐predict peak ground acceleration (PGA) and underestimate peak ground velocity (PGV) near the fault. The topographic amplification factors (TAFs) of PGA and PGV are found between 0.5 and 2.0, with a correlation coefficient of 0.7 between them. Predictive equations are proposed to correlate TAFs of PGA and PGV with topographic features, which are represented by relative heights obtained at different length scales. Finally, major earthquake damages are summarized with reference to the obtained ground motion intensity map.

Optimal intensity measures for probabilistic seismic demand models of steel moment frames

Selecting an optimal ground motion intensity measure (IM) is a vital step in the earthquake fragility analysis of building structures using probabilistic seismic demand models (PSDMs). This study proposes optimal IMs among 20 considered for seismic fragility analysis of structural steel moment frames in PSDMs. Five steel frames of different heights were selected to propose optimal IMs for steel frames between 2 and 20 stories. The IMs were evaluated using two engineering demand parameters (maximum interstory and roof drifts). Two characteristics of ground motions were investigated (pulse and non-pulse). The results revealed that velocity-related parameters (Housner intensity (HI) and peak ground velocity (PGV)) and spectral pseudo-acceleration at the first natural period (PSa(T1)) tend to be optimal IMs for steel moment frames. For maximum interstory drift, HI is suggested as the optimal IM for steel frames of 2–12 stories for both types of ground motions, while PGV is suggested for steel frames from 12 to 20 stories. Under maximum roof drift, PSa(T1) is the optimal IM for steel frames of all investigated stories subjected to either ground motion type. Peak ground acceleration, which is widely used as a ground motion IM, was observed to be unsuitable for all steel moment frames investigated in this study.

A Simplified Method for Performing Vector-Valued Probabilistic Seismic Hazard Analysis

ABSTRACT For a seismic risk analysis, the seismic hazard results are usually combined with fragility functions to calculate the probability of seismic losses. Because vector-valued ground-motion intensity measures (IMs) are increasingly used by researchers and practicing engineers to evaluate fragility functions, seismic hazard calculations in terms of vector-valued IMs are required, which are determined by vector-valued probabilistic seismic hazard analysis (PSHA). However, the large computational cost associated with vector-valued PSHAs impedes the application of vector-valued IMs in performing a seismic risk analysis. The study presents a simplified method for conducting vector-valued PSHAs. This simplified method is developed using proposed equivalent earthquakes that are derived from conventional seismic hazard deaggregation. Formulas for performing vector-valued PSHAs using the simplified method are also proposed. Based on a numerical example, this study demonstrates the accuracy and efficiency of the proposed method.

Ground Motion Models for Non-Spectral Intensity Measures Based on the Iranian Database

ABSTRACT An Iranian earthquake database has been employed to propose local empirical equations to predict non-spectral ground motion intensity measures, including Arias intensity, cumulative absolute velocity and duration of ground motions. The significant duration models have been considered 5% – 75% and 5% – 95% of Arias intensity in analyses. The bracketed and uniform duration models were proposed for absolute or relative acceleration thresholds, including 0.025g, 0.05g, 0.1g 0.025PGA, 0.05PGA and 0.1PGA. In this study, we used an updated dataset consisting of 2965 three-component time histories from 654 seismic events with the magnitude range 3.5 to 7.7 at distances less than 300 km recorded between 1975 and 2019. The functional form of the proposed models consists of some variables, including moment magnitude (Mw), Joyner-Boore distance (RJB), average velocity of shear waves for the upper 30-m depth (Vs30), and faulting mechanisms. The random-effects algorithm is used for conducting the regression analysis, which considers inter-event and intra-event error terms, separately. To verify the trend of attenuation in the proposed models, some comparisons have been made between the proposed models in the current study and those developed for other similar regions.