Earthquake-induced Deformation Research Articles

Prediction on the seismic performance limits of reinforced concrete columns based on machine learning method

The drift ratio or lateral deformation is typically applied as the indicator in order to evaluate the earthquake-induced damage, one of the most important issues is to determine the seismic performance level limits. Therefore, this study presents to predict the seismic performance level limits of RC columns by using the machine learning method. Firstly, a test database of the backbone curves of RC columns was established after collecting 754 specimens under axial and lateral loads. Then the seismic performance level limits of all the collected columns were taken out as the input values of machine learning. The correlations among the geometric, mechanical parameters and the performance limits of RC columns were analyzed based on Pearson correlation analysis and mutual information method. Afterward, regression models of seven machine learning methods were established to predict the performance level limits of RC columns, while the hyperparameters of the machine learning models were optimized by the grid search and cross-validation methods. The generalization ability of the prediction models was verified and evaluated by using mean square error, mean absolute error, maximum error and R square, meanwhile, the accuracy of the applied methods was also analyzed. The seismic performance level limits of RC columns determined by the machine learning method can comprehensively consider the influence of geometric and mechanical parameters of RC columns. Combined with the earthquake-induced deformation of RC columns, the seismic damage of RC columns can be evaluated reasonably, which is of great significance for evaluating the seismic damage of building structures. The discussion on the prediction accuracy among different machine learning algorithms is also beneficial for the deformation prediction of other RC components.

UAV-based investigation of earthquake-induced deformation and landscape changes: a case study of the February 6, 2023 Earthquakes in Hatay, Türkiye

UAV-based investigation of earthquake-induced deformation and landscape changes: a case study of the February 6, 2023 Earthquakes in Hatay, Türkiye

Earthquake-induced deformation at archaeological sites in southeastern Gorny Altai (Siberia, Russia)

Archaeoseismic studies in the Kurai Fault Zone in southeastern Gorny Altai (Siberia, Russia) reveal signatures of deformation caused by paleoearthquakes to burial and memorial sites (mound, khereksur, stone heap, stone enclosures), megaliths (steles), and irrigation ditch (suvak), which were located at the front of fault scarps or in their vicinity. The seismic motions left numerous traces of deformation: displaced of cairns of mound and khereksur; bending, displacement and rotation of parts of the khereksur's walls; bending stone structures at scarp crests; tilted and rotated enclosure's stone slabs; offset irrigation ditch; the displacement is most often directed. Dating of the archaeological site provides lower age bounds to the earthquakes. They all occurred for the past 3000 years, while the youngest events, ∼1.2 ka BP and no older than 1000 CE, were located in the northern Kurai and Kokorya basins, respectively. The deformation features in the mounds have bearing on the coseismic slip geometry.

Probabilistic seismic analyses of earthen levees with finite element modeling

Earthen levees are critical civil infrastructure of coastal regions for flood protection. Earthquakes can cause significant deformation and damage to earthen levees. Seismic performance of such levees under the earthquake hazards is a major concern in their safety evaluation. However, there are significant uncertainties in assessing the seismic behavior of earthen levees and geotechnical uncertainties play a critical role in the probabilistic assessment of earthquake-induced deformation and failures. This paper presents a simplified probabilistic framework for assessing the seismic performance of earthen levees with dynamic analysis and finite element modeling. In this framework, the effects of geotechnical uncertainties are explicitly considered in the uncertainty propagation for probabilistic evaluation of seismic deformations of earthen levees under earthquake hazards. The probability curves are developed to describe the correlations among the probability of exceedance, limiting deformation value, and input peak ground acceleration. The derived probability curves can provide valuable information for risk assessment and risk-informed decision-making of earthen levee infrastructure. The effectiveness of the proposed probabilistic framework is demonstrated through a case study of earthen levee example.

ПРОЯВЛЕНИЯ НЕОТЕКТОНИКИ В КАРСТОВЫХ ПОЛОСТЯХ: ОПЫТ ИДЕНТИФИКАЦИИ НА ПРИМЕРЕ ДЕНИСОВОЙ ПЕЩЕРЫ В ГОРНОМ АЛТАЕ

The article presents preliminary results of the study and characterization of the neotectonic processes manifestations in Denisova Cave, their influence on the formation and post-sedimentation changes of Pleistocene cave deposits. In Denisova Cave, traces of paleoearthquakes are examined in sections of sedimentary strata of the Main, East and South Chambers. The main types of earthquakeinduced deformations are described. A chronological assessment of the episodes of ancient seismic events recorded in the stratigraphic sequence of the cave is given. It was established that as a result of seismic deformations, the displacements of the layers turned out to be insignificant and their boundaries are well correlated. There was no mixing of the substance of different lithological units and, accordingly, the archaeological finds and paleontological material contained in them. We also assume that neotectonic activity could have infl uenced the living conditions of primitive man as one of the environmental factors.

Earthquake-induced risk assessment of cultural heritage based on InSAR and seismic intensity: A case study of Zhalang temple affected by the 2021 Mw 7.4 Maduo (China) earthquake

Earthquakes have been acknowledged as threats to heritages for a long time in the past decades. Many scientific publications and international guidelines have addressed this issue. However, the related reports are still lacking particularly for the 2021 Mw 7.4 Maduo earthquake and its surrounding heritage sites, even though this event was the largest earthquake in China after 2008 with 13 National Key Protected Cultural Relic Units (NKPCRUs) of China located in the surrounding areas within 200 km from the epicenter. On May 21, 2021, an Mw 7.4 earthquake struck Maduo County in Qinghai Province, China. The earthquake was large in magnitude and caused ∼150 km of surface rupture. The integrity and authenticity of cultural heritages near the epicenter are under severe threat, making it critically important to quantify the potential damages and vulnerability of these sites affected by the Mw 7.4 earthquake. Nevertheless, many geological and geophysical studies related to this earthquake have been conducted, but none of them consider the seismic damage to the heritage sites. To fulfill this gap, the Zhalang temple (also known as “Golok Peaceful Liberation Memorial”) which was a Tibetan Buddhist monastery located ∼140 km away from the Mw 7.4 epicenter of the 2021 Maduo earthquake was taken as an example to investigate whether and how the strong earthquake could affect a cultural heritage in such a distance. Collaborative monitoring based on InSAR and seismic intensity was conducted to measure the earthquake-induced deformation and characterize the risks and damages to cultural heritages by earthquakes. First, fast responses within 30 min based on the seismic method were performed. The PGV-vS30 intensity, that was the peak ground velocities (PGV) further site-corrected by the site conditions of the time-averaged shear-wave velocity to 30 m depth (vS30) seismic intensity map was obtained, which provided a general and fast guidance to preliminary determinations of the severe disaster area and the scope of the disaster area. Initial decisions could be made about whether or where a certain location should be taken into further on-site inspection. Then, the Interferometric Synthetic Aperture Radar (InSAR) processing of Sentinel-1 images was performed to define two-dimensional (2D) East-West (E-W) and vertical co-seismic deformation maps near the Zhalang temple. Finally, the measurements obtained by seismic and InSAR methods were validated by unmanned aerial vehicle (UAV) imagery and field surveying. The results showed that: the maximum E-W striking deformation was ∼2.54 cm toward the east and the vertical subsidence was ∼0.01 cm centered on the Zhalang temple, suggesting that the E-W striking deformation significantly affected the surrounding region. Moreover, the spatial heterogeneity indicator of the InSAR deformation maps revealed the locations of underground faults with surface expressions. Further field survey detected surface fractures at Zhalang temple due to secondary effects of the Mw 7.4 earthquake. The genetic process of faulting and fracturing is crucial in terms of hazard assessment and mitigation strategies. In countries with strong environmental and seismic risks, the presented work contributes to the disaster risk reduction (DRR) of heritages in natural-hazard-prone areas and also takes on a social value because it provided supplements for the protection of a heritage that represents the very identity nationwide.

Disentangling factors controlling earthquake-triggered soft-sediment deformation in lakes

In-situ soft sediment deformation structures (SSDS) are commonly used as paleoseismic indicators in marine and lacustrine sedimentary records. Earthquake-related shear can deform sediment in the shallow subsurface through Kelvin-Helmholtz instability. The SSDS related to Kelvin-Helmholtz instability have been used to quantify shaking strength of past earthquakes. However, the relative importance of i) lithology and physical properties, ii) potential basal shear surfaces (e.g. clastic deposits), iii) slope angle, and iv) seismic shaking strength (e.g. peak ground acceleration) for deformation related to Kelvin-Helmholtz instability remains poorly studied. Lake Riñihue (south-central Chile) is chosen as a natural laboratory for disentangling the effect of the aforementioned factors because i) the sediment composition of background sediment varies downcore and ii) volcanogenic clastic deposits are abundant within the sedimentary sequence. A previous study at lake Riñihue identified 25 SSDS intervals induced by historical earthquakes of varying rupture extent in 17 sediment cores taken at slope angles ranging from ~0.2° to ~4.9° (i.e. 16 slope sites and 1 basin site). Our study shows that deformation mostly occurs directly above volcanogenic deposits (i.e. 72 % of SSDS intervals), suggesting that volcanogenic deposits promote earthquake-induced deformation by strain softening, liquefaction or water film formation. Deformation thickness of SSDS increases with higher slope angles (i.e. strong positive correlation). Additionally, deformation thickness commonly corresponds to the stratigraphic depth of the youngest preceding volcanogenic deposit, but for steeper slope angles stratigraphically older volcanogenic deposits can function as basal shear surface. Therefore, we suggest that deformation thickness is primarily regulated by gravitational stress (i.e. slope angle) and secondarily by the stratigraphic depth of volcanogenic deposits. The earthquakes related to strongest shaking caused almost exclusively SSDS with highest deformation degrees (i.e. folds and intraclast breccia) as well as largest spatial extent of SSDS, resulting in highest numbers of related SSDS in the investigated cores. Thinner SSDS have higher deformation degrees at a given shaking strength, as seismically-induced shear energy acts more effectively on thinner deforming sequences. Therefore, we suggest that deformation degree is primarily controlled by shaking strength and secondarily modulated by the thickness of the deforming sequences. We infer that deformation thickness is not a reliable indicator of paleoseismic shaking strength as this relies on many preconditioning factors independent of shaking strength. On the other hand, deformation degree can be a good proxy for shaking strength also in settings with varying lithotypes and intercalated clastic event deposits, provided multiple cores are studied to avoid under- or overestimation of paleoseismic shaking strength.

Earthquake-Induced Ground Deformation Assessment via Sentinel-1 Radar Aided at Darbandikhan Town

Deformation monitoring has conventional increasing consideration in recent years due to its great importance in modern engineering. Darbandikhan town was hit by a strong earthquake on 12th November 2017 which is the Sarpol-e Zahab earthquake. Interferometric Synthetic Aperture Radar (InSAR) technique has been used to investigate Darbandikhan town stability and the surrounding areas of the Kurdistan region in Iraq. The purpose of this research is to estimate the ground vertical displacement induced by the earthquake as well as the east-west deformation components. Moreover, previous research covered more of Iran’s side country that the earthquake had an impact on with little on Iraq’s side (Northern-eastern of Iraq), so it was worth researching on Darbandikhan town and surrounding structures to estimate the displacement on its infrastructures. For this study, two pairs of Sentinel-1 Synthetic Aperture Radar (SAR) images are used from each ascending and descending tracks over the study area to validate the work. Then, two differential interferograms are created from these images, along Darbandikhan town and the surrounding areas. These differential interferograms are then converted to line of sight (LOS) displacements using open source software (SNAP 8.0). The overall vertical displacement of the residential area of Darbandikhan was estimated from -4 to -10 cm after the earthquake, and the overall east-west displacement was ranging from 2 to 6.4 cm. The current study does not only examine the northern east of Iraq but the whole area of Iran and Iraq in general that lies within the influence of the earthquake. This research could be useful to estimate the overall deformation of Darbandikhan town in particular and the whole area in general. Therefore, the authorities and civil engineers could think of more sustainable buildings and structures before they start to plan within the area of earthquake impact.

A fully nonlinear coupled seismic displacement model for earth slope with multiple slip surfaces

For slopes consist of layered soil profiles, the earthquake-induced deformation may occur in various locations and the slope may exhibit a set of plastic slip surfaces. In this paper, a fully nonlinear coupled sliding displacement model is presented to evaluate the seismic performance of slopes considering multiple slip surfaces. Both the nonlinear behavior in the cyclic response of soils and the sliding process at different slip surfaces are described based on a multi-degree-of freedom lumped parameter model. The nonlinear hysteretic soil response is represented by the hyperbolic stress-strain curve and the Masing rules. The yield coefficients obtained from pseudo-static analysis of slopes are used to represent the limit shear strength at each slip surface. The dynamic equations of motion of the system in the cases of various sliding modes at shallow, median and deep slip surfaces are derived, and the sliding displacements at different locations of slopes during the earthquake motion can be computed. The code is validated by degrading the developed model to the conventional seismic site response analysis and seismic sliding analysis models. The sliding displacement at different slip surfaces and the stress-strain results of soil are analyzed to highlight the coupling effects of the plastic shear deformations at different slip surfaces and the cyclic responses of soil. The comparisons of displacement results for different slopes are then performed between the proposed model and the linear soil model and the single sliding analysis model. Finally, an application to the Bainigou slope is presented to evaluate the seismic performance of the slope.

Seismic performance improvement of underground frame structures by changing connection type between sidewalls and slab

Seismic failure mechanism of underground frame structures presents that the collapse of underground structures attributes to the insufficient seismic resistance of central columns. Therefore, researches have been conducted to improve the seismic performance of underground structures by enhancing the loading-carrying capacity of the central columns or decreasing the seismic loads transmitted to central columns. For this purpose, this study proposed a new approach by changing the connection type between sidewalls and slab: setting shock absorbing gap (SAG) between sidewalls and ceiling slab, which aims to decrease seismic loads transmitted to central columns. The proposal and working mechanism of SAG were illustrated detailedly. Afterwards, nonlinear finite element models, in which a developed elastoplastic constitutive model was used to simulate the 3D strength and softening behaviour of surrounding soils, were built for simulating the static and dynamic responses of underground structures. Based on the numerical results, SAG affecting the internal forces of structural components before earthquakes were discussed firstly. Then the seismic efficiency of SAG updating the seismic performance of underground frame structures was analyzed by discussing earthquake-induced damage mode of overall structures, soil pressure on structures, earthquake-induced deformations and internal forces of structural components. Finally, the seismic performance of underground frame structures influenced by the width of SAG and frictional coefficient of the sliding surface was investigated, and advice for reasonably using SAG was suggested.

Late Glacial and postglacial seismicity in the Northeastern Fennoscandian Shield: tectonic position and age of paleo-earthquakes near Murmansk

Earthquake-induced deformations located near Murmansk City were investigated for information on the age, tectonic position and spatial occurrence of paleo-earthquakes. The main earthquake-generating zone is identified to be the system of strike slip faults and reverse-oblique faults trending NNW along the Kola River valley. We used radiocarbon analysis and paleogeographic reconstructions and revealed three episodes of increased seismic activity: from 9500 to 10500 cal BP, from 892 to 1182 cal BP, and from 200 to 300 cal BP. Based on the peak ground velocity estimation method we suggest that an earthquakes with a maximum moment magnitude up to Mw ≈ 6.0–6.5 may have taken place in the studied area. The recorded location of seismogenic deformation near faults indicates area of strong Late Glacial and Holocene earthquakes occurring in the northern Kola Peninsula; this is also consistent with observations concerning the historical events of 1772 and 1873, which took place near the area.Combined with previous data on palaeoseismicity in Kola region, our studies indicate a longer lasting and more complex spatial and temporal history of postglacial seismicity in the Northeastern Fennoscandian Shield area. In contrast to the generally accepted opinion, strong seismic events occurred not only during the deglaciation period or immediately after it, but continued until the late Holocene and the last centuries. Glacial isostasy as a factor giving rise to stresses has become minimal by the present time, while the tectonic factor continues to be felt.

GEOTECHNICAL SEISMIC ISOLATION METHOD USING RUBBER-SOIL MIXTURES

Seismic isolation is a method of protecting a building from earthquake-induced deformations by using isolators and devices under the superstructure. The purpose of the seismic isolation method is to reduce the earthquake forces transferred from the ground to the structure by placing energy-absorbing elements between the foundation and superstructure. Especially in developing countries, the "Geotechnical Seismic Isolation (GSI)" system has been proposed as a new isolation method to reduce earthquake-induced damages on buildings. In this study, it is aimed to reduce the effects of earthquakes in a multi-story building with an isolation layer formed with a mixture of rubber-sand (RSM). For this purpose, a 10-story reinforced concrete building was modeled numerically. A seismic energy absorbent RSM layer was placed beneath the foundation of the building. Geosynthetic layers are used to prevent the contact of the RSM layer with the natural soil. The developed model was tested under real earthquake motions with varying amplitudes. The performance of the developed RSM layer has been evaluated in terms of reducing the earthquake effects on the analyzed building model. The analysis was carried out with the dynamic module of the PLAXIS 2D finite element program.

Delineating the spatial distribution of soil liquefaction potential in a cross-section from limited cone penetration tests

The damage caused by soil liquefaction during earthquakes is substantially affected by the total volume and spatial distribution of the liquefied soils. Therefore, a proper characterization of the spatial distribution of liquefaction potential of subsurface soils plays a critical role in earthquake hazard assessment and mitigation. In engineering practice, in situ tests, such as the cone penetration test (CPT), are widely used for evaluating soil liquefaction potential through, e.g., factor of safety (FS) against liquefaction, and the results of liquefaction assessment in a cross-section are needed for subsequent earthquake hazard analysis and mitigation. Traditional simplified methods only provide the liquefaction potential of soils at individual locations, and the results of liquefaction triggering evaluation at individual locations are often used to represent the whole site. This might lead to an unconservative estimation of earthquake-induced deformations and damage at a site where spatial variation of soil properties is significant. In addition, although CPT provides almost continuous sounding along vertical direction, measurements along horizontal directions are usually limited. This leads to the difficulty in proper application of geostatistical methods in liquefaction potential analysis. To address these challenges, a non-parametric and data-driven method is developed in this study to interpret a cross-section of FS with high spatial resolution directly from sparse CPT soundings. Based on the interpreted cross-section of FS, the predicted total volume and spatial distribution of liquefied soils are estimated. Both simulated and real CPT data are used to demonstrate and validate the proposed method, and the results show that the proposed method performs reasonably well.

Detection and evaluation of earthquake-induced deformation of reclaimed valleys using synthetic aperture radar interferometry, Structure from Motion and Multi-view Stereo technology

Detection and evaluation of earthquake-induced deformation of reclaimed valleys using synthetic aperture radar interferometry, Structure from Motion and Multi-view Stereo technology

A non-linear static approach for the prediction of earthquake-induced deformation of geotechnical systems

This paper illustrates an original and simple method to predict earthquake-induced deformations of geotechnical systems. The method is an extension of static non-linear analysis, and is conceived to predict the behaviour of geotechnical systems, like supported and unsupported excavations, that during the seismic motion accumulate displacements in a single direction. The seismic capacity of the system is described by its capacity curve, obtained either from a numerical push-over analysis or through a simplified procedure. The corresponding seismic demand is described by a combination of the elastic response spectrum, including basic information on the maximum amplitudes of the seismic motion, and a cyclic demand spectrum, that provides additional information about the equivalent number of cycles that contribute to the accumulation of displacements. In the paper, the method is described in detail and is validated through different procedures, namely: comparisons with experimental results obtained in the geotechnical centrifuge; comparison with results of advanced numerical analyses; extensive comparison, using a large database of seismic records, with the results of non-linear time-domain analyses. In its final part, the paper provides guidance for the practical use of the method for design.

Numerical Simulations of Fourth Avenue Landslide Considering Cyclic Softening

Cyclic softening of fine-grained soils poses a significant hazard to geotechnical infrastructure in many parts of the world. Methods to numerically evaluate the cyclic softening and subsequent localization behavior in clays in practice are less developed than techniques to model liquefaction-induced strength loss of granular soils. The PM4Silt constitutive model can model the dynamic response of low-plasticity silts and clays while being relatively easy to calibrate and use. This paper investigates the ability of PM4Silt to model earthquake-induced deformations caused by strain-softening of a mildly sensitive clay. The Fourth Avenue landslide that occurred in Anchorage, initiated by the 1964 Great Alaska Earthquake, is used in this evaluation. Results from previous studies are used to estimate site stratigraphy and relevant soil properties. The model calibration procedures and results are discussed. Simulation results using PM4Silt are compared with the observed displacements and results from previous studies using different constitutive models. The effects of different model calibrations are studied, as well as the influence of input motion and mesh density. The results demonstrate the PM4Silt is able to capture the general response of the Fourth Avenue landslide, although the results are sensitive to the input parameters and show some dependency on mesh size.

Coupled analysis of earthquake-induced permanent deformations at shallow and deep failure planes of slopes

The seismic performance of slopes is commonly evaluated by simplified sliding block analyses. In this paper, an extended sliding block model is developed to compute the earthquake-induced deformations at both shallow and deep failure planes of slopes. The coupled analytical model captures simultaneously the stick-stick, stick-slip and slip-slip behaviors of the lumped mass system of soil profile. The complex interactions between the dynamic response of the soil and the slip episodes at shallow and deep slide planes are revealed. The proposed sliding model is compared to the conventional single base-sliding analyses, and the influence of the presence of shallow failure sliding is emphasized. Then, the dynamic response and permanent displacement of slopes with different locations of the shallow sliding plane and different yield accelerations of shallow and deep sliding planes are examined. The comparisons are also performed for permanent displacements determined from the developed coupled multi-sliding procedure and from the seismic sliding model with multiple rigid blocks. Finally, an example is presented to demonstrate the procedure in the application and the differences of the results from the traditional coupled approach. The coupled model in this study provides a rigorous procedure to combine the shallow and deep failure modes for the assessment of the co-seismic landslide hazard.

Earthquake-induced deformation structures in glacial sediments—evidence on fault reactivation and instability at the Vaalajärvi fault in northern Fennoscandia

Late and postglacial reverse faults and seismically-induced landslides are characteristic features of deglaciated terrain in the northern Fennoscandia. The main focus of this study was to investigate the rupturing history of the reverse Vaalajarvi fault complex in Sodankyla, Finland, based on remote sensing, on-site geophysics and sedimentology in excavations trenched across the faulted terrain. In addition to the previously known NNW–SSE-trending Vaalajarvi segment, we discovered six new SW–NE-trending fault segments that probably belong to the same Vaalajarvi ‘postglacial’ fault complex. Our analysis indicate that the Vaalajarvi fault segment was triggered by stress change caused by ruptures on the surrounding SW–NE-trending reverse faults. In total, at least two to three slip events have taken place in different segments of the Vaalajarvi complex since the Early Weichselian with the most recent event(s) being postglacial in timing. By using the scaling laws of fault surface rupture length and offset and under different scenarios of which segments or systems ruptured in a single or separate event, we estimate that the Vaalajarvi complex potentially hosted an earthquake that ranged between Mw ≈ 6.7–7.0. This magnitude is comparable to the landslide-inferred magnitudes in the Vaalajarvi area.

Numerical Modeling of Wave Feature to Enhance the Performance of Buried Steel Pipelines Subjected to Faulting Displacements

Earthquake-induced permanent ground deformations are among the most important causes of damage to lifelines. Buried pipelines are longitudinal structures that are prone to be exposed to the faulting displacements. Improving the performance of these lifelines is of particular importance. This research numerically investigates the effect of a recently introduced wave feature (segments with rotational and axial flexibilities) on the behavior of buried pipes subjected to the displacement of the strike-slip faulting. Three-dimensional nonlinear finite element simulations were conducted in which the pipe and wave feature were modeled by shell element and peripheral soil was modeled by three-dimensional continuum elements. The accuracy of numerical simulations was examined by comparing the results with large-scale physical experiment. The comparison shows that the results of numerical modeling are in good agreement with experimental results. As an advantage of a calibrated numerical simulation, it is possible to extend the range of predictions and get the generalized response of the system in other geometrical and boundary conditions in which the experimental data are not available. In order to study the effect of the wave feature joint on the behavior of buried pipeline, the results were compared with a pipe with identical conditions in which the wave feature was not installed. It was found that wave feature substantially reduces the longitudinal forces and strains and preserves the cross-sectional area of the pipeline. Therefore, it considerably improves the performance of the pipe against faulting displacements.

Behavior Analysis on Earthquake-Induced Deformation of Quay Wall and Apron in Ground at Youngilman Port Considering Drainage Condition Using FEM Analysis

Behavior Analysis on Earthquake-Induced Deformation of Quay Wall and Apron in Ground at Youngilman Port Considering Drainage Condition Using FEM Analysis