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Dynamics of Liquefaction During the 1987 Superstition Hills, California, Earthquake
Abstract
Simultaneous measurements of seismically induced pore-water pressure changes and surface and subsurface accelerations at a site undergoing liquefaction caused by the Superstition Hills, California, earthquake (24 November 1987; M = 6.6) reveal that total pore pressures approached lithostatic conditions, but, unexpectedly, after most of the strong motion ceased. Excess pore pressures were generated once horizontal acceleration exceeded a threshold value.
... Gracias a los registros sísmicos y piezométricos obtenidos durante este terremoto, se han verificado varios planteamientos realizados a partir de ensayos de laboratorio y llegado a grandes enseñanzas sobre el comportamiento sísmico de los suelos potencialmente licuables [4], [5], [7], [20], [21], las cuales se presentan de forma compilada a continuación: ...
... Luego, el modelo calibrado fue sometido a más de 30 sismos de diferentes características variando el nivel de aguas freáticas del modelo: con el nivel de aguas freáticas por encima del estrato potencialmente licuable (estado saturado del estrato licuable), y con el nivel de aguas freáticas en la base del estrato potencialmente licuable (estado seco del estrato licuable). Este ejercicio se realizó con el objetivo de cuantificar los principales cambios esperados en la respuesta sísmica de este tipo de depósitos de suelos debido a la saturación del estrato licuable, y que han sido reportados en la literatura, como son: la pérdida de rigidez del estrato potencialmente licuable a medida que el exceso de presión de poros aumenta [5]; los cambios en el periodo predominante de vibración del depósito de suelo [4], [7], [38]; la deamplificación de la aceleración en superficie y la amplificación de los desplazamientos en superficie [62]; el aumento del desplazamiento espectral en superficie para periodos medios y altos [63]; entre otros. ...
... En efecto, el desarrollo de un centro de monitoreo sísmico en este sector de la ciudad será una herramienta importante para los estudios de amenaza y riesgo sísmico, tanto de la PTAP de Puerto Mallarino, como del oriente de la ciudad. 4. Diseño e implementación de un centro de monitoreo sísmico para el estudio de los depósitos de suelos potencialmente licuables de Cali (Colombia) ...
DEVELOPMENT AND IMPLEMENTATION OF A METHODOLOGY TO EVALUATE THE SEISMIC RESPONSE OF SOIL DEPOSITS WITH POTENTIALLY LIQUEFIABLE NON-SHALLOW LAYERS.
Liquefaction poses a significant natural hazard to Cali, Colombia, particularly for the 880 thousand inhabitants residing on the alluvial deposits along the Cauca River. Despite its gravity, studies examining the seismic response of this region have been scarce, mainly due to the challenges in simulating the behavior of deposits containing potentially liquefiable soils. This issue is exemplified in the seismic microzonation study of Cali, where the response spectra obtained for this area show a limited fit with seismic records from the site.
This research aims to develop and implement a methodology to accurately estimate response spectra of Cali soil deposits containing potentially liquefiable layers, to have effective tools to evaluate the different scenarios of seismic hazard and risk to which the inhabitants of areas susceptible to liquefaction in the city are exposed. To develop the methodology, first, a study of the seismic behavior of soil deposits with potentially liquefiable layers was carried out by analyzing data from two seismic monitoring centers that were built for the study of this phenomenon (WLA and GVDA). Subsequently, numerical modeling of one of these centers was used to explore the most appropriate approach to simulate the seismic response of such soil deposits.
Drawing from the findings and conclusions, a methodology was devised and implemented to investigate the seismic response of the alluvial deposits along the Cauca River in Cali. This implementation involved a comprehensive geotechnical and dynamic characterization study, incorporating field tests, laboratory analyses, and examination of seismic records. Based on this characterization and preliminary studies, a seismic monitoring center was designed, constructed, and put into operation specifically for studying potentially liquefiable soil deposits in Cali -marking the first of its kind in Latin America-. Finally, using the geotechnical data and seismic records obtained from the monitoring center, a seismic response model was developed and adjusted for Cali's potentially liquefiable deposits. This model enabled the accurate simulation of the soil's seismic response and the generation of realistic response spectra for the studied area.
... During liquefaction, a weakly consolidated (contractive) and saturated granular soil loses, entirety or partially, its shear strength. This phenomenon is associated with the softening that these soils exhibit when the frequency contents and amplitude of the earthquake trigger an excessive increase in porewater pressure [17]. At the point when pore pressure ratio |r u | (the ratio of the excess pore pressure to the initial effective confining stress) equals or is close to unity, or when some threshold of cyclic shear strain amplitude is reached, liquefaction is said to occur. ...
Several probabilistic liquefaction triggering approaches, or liquefaction manifestation severity approaches, have been developed to consider the uncertainties related to liquefaction and its manifestations. Probabilistic approaches are essential for vulnerability and risk models that considers the consequences of liquefaction on building performance. They may be incorporated into a performance-based earthquake engineering framework through a fully probabilistic liquefaction hazard assessment. The objective is to effectively incorporate spatial interaction of two concurrent hazards, specifically earthquake-induced shaking, and liquefaction, and to develop a robust multi-hazard framework applicable to regions with limited input data. For this purpose, it is necessary to establish, according to the available probabilistic liquefaction triggering or manifestation severity assessment approaches, which set of approaches aligns optimally with vulnerability and risk models. Thus, this paper discusses the current methodologies on the ongoing probabilistic liquefaction hazard assessment approaches with the aim of defining a reliable model specific for areas with a non-liquefiable surface layer over a liquefiable layer.
... The 1987 Superstition Hills Earthquake was the only liquefaction event captured by the site instrumentation which was also evidenced by surface manifestations. The 1981 liquefaction event was only evidenced by surface manifestation of ejecta [21,31,[36][37][38]. While the site was also subjected to the 7.2 M w El Mayor-Cucupah earthquake in 2010, the site did not liquefy, based on both the instrumentation as well as the lack of ejecta. ...
... Ground motion records, which are the direct result of massive earthquakes and offer important insight into the ground motion features, are fundamental study data for seismology and earthquake engineering [1]. Since earthquake hazard assessment studies have been used to look into nonlinear soil reactions and geological disasters like sand liquefaction and tsunamis, in addition to the causes of structural damage in strong earthquakes, an understanding of the mechanism underlying acceleration spikes in ground motion is beneficial [2][3][4][5]. Due to developments in strong motion observation technology, seismologists and engineers are becoming increasingly concerned about the collection of strong motion records, particularly the PGA greater than 1 g [6][7]. These anomalous records with acceleration spikes are extremely valuable for investigating near-surface nonlinear behavior to better understand the soil response and the process of anomalous acceleration spike generation, as well as to minimize damage from devastating earthquakes. ...
Strong motion records with acceleration spikes have occurred frequently in recent major earthquakes, acceleration spikes contribute to the peak ground accelerations (PGAs) and the amplitudes are significantly higher than the predicted values based on present attenuation relation. The generation mechanism of acceleration spikes is revealed based on long-term monitoring after the 2008 Mw 8.0 Wenchuan earthquake. The horizontal accelerogram with obvious spikes from the Mw 9.0 Tohoku-Oki earthquake is reproduced by using numerical simulation, and it’s found that the dilatancy cyclic mobility (DCM) mechanism can explain the generation of acceleration spikes. The support vector machine (SVM) is used to efficiently identify DCM sites. We found that the spatial distribution of DCM sites is parallel to the earthquake source fault and the corresponding PGAs of ground motions recorded in DCM sites differ significantly from those recorded in non-dilatancy cyclic mobility (NDCM) sites.
... Typical predictions with the above simplified methodologies are shown in Figures 4a & b, for two field case studies: the Superstition Hills (1987, Mw = 6.6) earthquake recorded at the Wildlife liquefaction array (WLA) in USA (Holzer et al. 1989) and the Kobe (1995, Mw = 6.9) earthquake recorded at the Port Island downhole array (PIDA) in Japan (Iwasaki and Tai 1996). In both cases, acceleration time-histories were recorded at the ground surface, as well as below the liquefied layer. ...
The common design practice for the foundation of heavy structures, such as bridge piers, in liquefaction prone areas is to use piles in order to transfer the foundation loads to deeper non-liquefiable soil layers. In parallel, it is often required to improve the liquefiable soil layers between and around the piles so that bending moments and pile head deflections do not become excessive. Nevertheless, recent experimental and theoretical studies suggest that the existence of a natural or artificially created (i.e. by ground improvement) surface “crust” of non-liquefiable soil, may mitigate the consequences
of liquefaction in the subsoil, so that the use of shallow foundations becomes also permissible. In view of the above, a four-year research project was undertaken, aiming at extending and rationalizing the above findings into a novel practically oriented methodology for the seismic design of low cost surface foundations on liquefiable soils covered by a non-liquefiable “crust” of improved ground. Apart from replacing the more expensive pile foundation, this new design concept has the additional advantage of drastically reducing the inertia forces acting on the superstructure, as the unimproved liquefiable soil layers (below the crust) will act as a natural seismic isolation system. This paper presents the milestones of the performed research, with emphasis on assumptions and results, as well as on references for further study. The anticipated benefits from the new design approach are evaluated by means of a pilot application for relatively heavy superstructure conditions, namely for three common bridge types with different construction material and structural system: a statically determinate RC bridge; a statically indeterminate RC bridge; and an arch steel bridge.
... Experimental studies related to dynamic characteristics and liquefaction resistance of unreinforced and different geosynthetic material-reinforced pond/fly ash are reported by Singh and Singh (2022), Ram and Mohanty (2021), Chowdhury and Patra (2022), Chattaraj and Sengupta (2017), Vijayasri et al. (2016), Samal et al. (2016), Mohanty and Patra (2014), Jakka et al. (2010b), Dey and Gandhi (2008) and Boominathan and Hari (2002). Previously several researchers performed numerical investigations on liquefaction-influenced deformation of sloping ground and earth/gravity dams under earthquake excitation (Li et al. 2021;Rampello et al. 2009;Parra 1996;Zeghal and Elgamal 1994;Holzer et al. 1989;Seed 1979). In India, most earthquakes are generated from the Himalayan Frontal Front (HFF) and affect different sites along the Indo-Gangetic Plain. ...
In the present study, pond ash from Panki thermal power plant, India (seismic zone III), has been reinforced with geogrid layers and the influence of reinforcement on dynamic shear modulus, material damping ratio, degradation index and resistance to liquefaction of pond ash samples has been investigated. The static and dynamic properties of ash samples without and with geogrid reinforcement have been determined by laboratory experiments. Further, these properties have been used in the dynamic response analysis of the two-dimensional domain of the Panki pond ash deposit that is pond ash column reinforced without and with geogrid. The OpenSees (Open System for earthquake engineering simulation) software is used to perform the analysis. Three moderate magnitude earthquakes (Chamba, Chamoli and Uttarkashi) of Himalayan origin have been considered to study the variations of acceleration, displacement and excess pore water pressure ratio with time for different layers of pond ash columns without and with geogrid reinforcement. Cyclic triaxial experiments show that due to the provision of geogrid reinforcement, the dynamic shear modulus increases about 13% to 81.6% and the liquefaction resistance increases about 91–162%. The dynamic response analysis shows that for geogrid-reinforced pond ash column, the peak ground acceleration (PGA) value decreases about 32–33%, 17–22% and 13.5–18% and the peak ground displacement (PGD) value decreases about 23.5–39%, 18.5–20% and 13–17% as compared to unreinforced pond ash column for Chamba, Chamoli and Uttarkashi earthquakes, respectively.
The residual shear strength of liquefiable soil plays an important role in evaluating the displacement magnitude of lateral spreading when applying the Newmark sliding block method. Currently, the empirical model is a mainstream alternative method for estimating the residual shear strength. In this study, a database of well-documented lateral spreading cases is used to establish an exponential function for residual shear strength evaluation correlated with the vertical effective stress and normalized standard penetration test blow counts for liquefied soil. A comparative analysis with two other empirical models is conducted, and the lateral spreading of the Wildlife Site during the Superstition Hills earthquake in 1987 is estimated using the Newmark sliding block method. The model exhibits good performance for soil residual shear strength estimation in cases of liquefaction-induced lateral spreading. The average estimated value of the residual shear strength may be appropriate for deterministic analyses in engineering practice.
There is a strong correlation between Arias intensity and the possibility of earthquake-induced landslides. Since landslides have distinct sliding directions, it is necessary to investigate the directional characteristics of Arias intensity. The free-field recordings from 40 stations within 200 km of fault distance in the Wenchuan Mw 7.9 earthquake were selected for this study. We discovered that the fluctuation of Arias intensity with azimuth exhibits distinct features of cosine (or sine) curve with a period of 180◦, and we proposed a theoretical expression (Eq. 3) of Arias intensity considering directionality using the maximum value (Ia100), the minimum value (Ia00), and the polarization direction (Amax). The maximum-to-minimum ratios of Arias intensity (Ia100/Ia00) decrease as fault distance increases and can be represented as a piecewise linear decreasing relationship that declines significantly faster in the near-middle field than in the middle-far field. The polarization directions (Amax) for stations near the epicenter are consistent with the coseismic displacement directions, which should be further validated by testing various faulting styles; an estimated equation for the azimuth of the projection of the trace of fault movement on the ground surface was employed to predict Amax using the fault’s strike, dip, and rake. Finally, we provided a framework for constructing empirical directional model of Arias intensity using the traditional attenuation relationship, the empirical relationship of Ia100/Ia00, and the estimated equation of Amax, as well as thereby a method for predicting Newmark displacement considering directionality. There is an imperfect solution for Amax estimation, other than our work would still serve as a point of reference for future research into the regional directionality of Arias intensity.
In light of inherent errors associated with the existing methods for predicting lateral spreading of liquefied soil during earthquakes, a novel approach has been proposed. Based on the Newmark sliding block method, a neural network model has been trained to calculate lateral liquefaction displacement, which was achieved by compiling a substantial dataset and establishing a comprehensive seismic motion database. Taking into consideration six input features to train the sensitivity model, based on the sensitivity analysis, a predictive model for liquefaction-induced lateral spreading was developed include three parameters, moment magnitude, peak ground acceleration and yield acceleration. This model was then compared to empirical lateral spreading prediction models. The results demonstrate that this model shows notable concurrence with the existing empirical models. Additionally, using 22 well-documented cases of liquefaction-induced lateral spreading, three high-quality models were employed to predict residual shear strength of the soil. Notably, this novel model surpasses the performance of empirical liquefaction-induced lateral spreading prediction models.
In the 90 days following the Oroville, California, earthquake (August 1, 1975; ML = 5.7), 313 positively identified strong-motion accelerograms were obtained for 86 different aftershocks. This set of records samples a wide range of magnitude (1.8 ≦ ML ≦ 5.2), focal depth (2 ≦ h ≦ 12 km), and site conditions (Holocene alluvium to Mesozoic crystalline basement). Most of these records were written at hypocentral distances R ≦ 15 km, a distance range for which relatively few strong-motion accelerograms had previously been available. Equally significant is the completeness of coverage (seven or more positively identified records) available for each of 12 well-recorded aftershocks (2.8 ≦ ML ≦ 4.9). One hundred and sixty-five peak acceleration values at 6.7 ≦ R ≦ 15 km for 33 aftershocks (3.0 ≦ ML ≦ 4.9) are the basis of an investigation of the dependence of peak acceleration on magnitude at R ≃ 10 km. These observations are supplemented with one datum for the main shock, 6 observations for two ML ≧ 5 aftershocks, and 61 null observations. Peak accelerations at sites on bedrock or minor sedimentary thicknesses are consistently higher than those at sites on several hundred meters or more of sedimentary rocks. Mean values for both site classes of data increase fairly rapidly with magnitude for 3 ≦ ML < 5, but the little available data for ML ≧ 5 suggest this magnitude dependence abruptly terminates at ML ≃ 5. The magnitude dependence of the sedimentarysite data is apparently stronger than for the bedrock-site data. Much if not all of the apparent magnitude dependence of these data can be attributed to properties of the path and not the source, consistent with the hypothesis that the amplitude of the peak acceleration phase, as it leaves the source region, does not depend on source strength although the predominant frequency of this phase increases as the duration and magnitude of the earthquake decreases.
Eight records of seismic-induced pore-water pressure and corresponding acceleration records were gathered from aftershocks of the 25 to 27 May 1980, Mammoth Lakes, California, earthquake sequence. The records were obtained from lakeshore sediments at Convict Lake that had undergone liquefaction and subsequent lateral-spreading failure. The pore-pressure records showed several similarities to corresponding strong-motion acceleration records. The pore-pressure traces show clear P- and S-wave phases and are in phase with corresponding P-wave components of the acceleration records. S-wave components of pore-pressure records appear most similar in waveform to one or the other of the corresponding horizontal acceleration components. Although the P-wave portions of pore pressure are in phase with their acceleration counterparts, the amplitudes are not related by a strictly proportional factor. S-wave portions of the porepressure records show a phase lag compared to the S wave of the respective acceleration trace. In most cases, the frequency of the pore-pressure S-wave components are also about 5 Hz lower in frequency than the acceleration S waves.
An analytical procedure is presented for evaluating the general characteristics of pore-water pressure buildup and subsequent dissipation in sand deposits both during and following a period of earthquake shaking. It is shown that in layers of fine sand, excess hydrostatic pressures may persist for an hour or more after an earthquake. However evidence of subsurface liquefaction may not appear at the ground surface until several minutes after the shaking has stopped and the critical condition at the ground surface may not develop until 10 min-30 min after the earthquake. However, for coarse sands and gravels with an impedance of drainage due to the presence of sand seams or layers, pore pressures generated by earthquake shaking may dissipate so rapidly that no detrimental build-up of pore pressure or a condition approaching liquefaction can develop. Improving the drainage capability of a sand deposit may thus provide an effective means of stabilizing a potentially unstable deposit. Analyses of the type described also provide the means for assessing whether subsurface liquefaction will have any serious effects on structures supported near the ground surface.
Following the successful measurements of accelerations and pore water pressure rise during the 1980 September 25 earthquake, a new set of piezometers embedded in the sand deposit on the Owi No. 1 Island in Tokyo Bay was again installed at the same site in a bid to monitor pore water pressures awaiting a reasonably large earthquake to come. On October 4, 1985, an earthquake of magnitude of 6. 2 shook the area of Tokyo Bay and pore water pressure rise was again monitored, together with the accelerations on the ground surface and in the deposit at a depth of 10 m. The maximum ground surface acceleration recorded was 71 gal and the pore water pressure increase at depths of 6 m and 14 m was 4. 5% and 5. 3% of the mean effective confining pressure, respectively. On the basis of the laboratory test results performed previously on undisturbed soil specimens, an estimate was made of the pore water pressures that might be produced in the deposit by the seismic shaking with a maximum acceleration of 71 gal. The estimated values of pore water pressure were shown to be somewhat larger than that registered during the earthquake.
Every constituent of nuclear power plants is classified into three ranks ; of A, B, and C from the point of safety. Aseismatic design method is adopted ; corresponding to the importance of each constituent. ASME Section III classifies ; the piping into Class-1 and Class-2. The design of the Class-1 piping is applied ; to A class piping, and that of Class-2 piping is applied to B class one. The ; ASME Section III defines five conditions of Design, Normal, Upset, Emergency and ; Faulted for the Class-1 piping components, and decides allowable stress ; corresponding to the sort of the stress. For the dynamical analysis of pipings, ; there is the method to treat the pipings as continuuan (DINAPS) and there is the ; method to treat the pipings as models consisting of material points and elastic ; rods. The dynamic analysis contains eigenvalue analysis and earthquake response ; analysis. The eigenvalue analysis of complex structures is performed by using a ; large matrix method and transfer matrix method. A code DIANA III, which Japan ; Atomic Power Corporation has developed, uses the transfer matrix method, which is ; described. The earthquake response analysis is classified into time-history ; analysis and modal analysis is used for the response analysis of pipings. (JA);
Late Holocene marsh deposits composing a terrace about 55 km northeast of Los Angeles, California, contain geologic evidence of many large seismic events produced by slip on the San Andreas fault since the sixth centrury A.D. I excavated several trenches into the deposits in order to study this evidence. The principal indicators of past events are (1) sandblows and other effects of liquefaction, (2) the termination of secondary faults at distinct levels within the stratigraphic section, and (3) sedimentary deposits and faulted relationships along the main fault. The effects upon the marsh deposits of six of the eight prehistoric events are comparable to those of the great (Ms=81/4+) 1857 event, which is the youngest of the nine events disturbing the strata and is associated with about 41/2 m of right lateral slip nearby. Two large events may be smaller than this. Radiocarbon dates indicate that the events occurred in the nineteenth, eighteenth, fifteenth, thirteenth, late twelfth, tenth, ninth, seventh, and sixth centuries A.D. Recurrence intervals average 160 years but vary from 1/2 century to about 3 centuries. The dates may indicate a fairly systematic pattern of occurrence of large earthquakes.
Data from 40 historical world-wide earthquakes were studied to determine the characteristics, geologic environments, and hazards of landslides caused by seismic events. This sample of 40 events was supplemented with intensity data from several hundred United States earthquakes to study relations between landslide distribution and seismic parameters. Fourteen types of landslides were identified in the earthquakes studied. The most abundant of these were rock falls, disrupted soil slides, and rock slides. The greatest losses of human life were due to rock avalanches, rapid soil flows, and rock falls. Correlations between magnitude (M) and landslide distribution show that the maximum area likely to be affected by landslides in a seismic event increases from approximately 0 at M ≅ 4.0 to 500,000 km2 at M = 9.2.
Threshold magnitudes, minimum shaking intensities, and relations between M and distance from epicenter or fault rupture were used to define relative levels of shaking that trigger landslides in susceptible materials. Four types of internally disrupted landslides—rock falls, rock slides, soil falls, and disrupted soil slides—are initiated by the weakest shaking. More coherent, deeper-seated slides require stronger shaking; lateral spreads and flows require shaking that is stronger still; and the strongest shaking is probably required for very highly disrupted rock avalanches and soil avalanches.
Each type of earthquake-induced landslide occurs in a particular suite of geologic environments. These range from overhanging slopes of well-indurated rock to slopes of less than 1° underlain by soft, unconsolidated sediments. Materials most susceptible to earthquake-induced landslides include weakly cemented rocks, more-indurated rocks with prominent or pervasive discontinuities, residual and colluvial sand, volcanic soils containing sensitive clay, loess, cemented soils, granular alluvium, granular deltaic deposits, and granular man-made fill. Few earthquake-induced landslides reactivate older landslides; most are in materials that have not previously failed.
The purpose of this paper is to clarify the meaning of the values of standard penetration resistance (SPT) used in correlations of field observations of soil liquefaction with values of N//1 measured in SPT tests. The field data are reinterpreted and plotted in terms of a newly recommended standard, (N//1)//6//0, determined in SPT tests where the driving energy in the drill rods is 60% of the theoretical free-fall energy. Energies associated with different methods of performing SPT tests in different countries and with different equipment are summarized and can readily be used to convert any measured N-value to the standard (N//1)//6//0 value. Liquefaction resistance curves for sands with different (N//1)//6//0 values and with different fines contents are proposed.
The nearly conincident forms of the relations between seismic moment Mo and the magnitudes ML, Ms, and Mw imply a moment magnitude scale M=2/3 log Mo-10.7 which is uniformly valid for 3