scholarly journals Hazard-Consistent Earthquake Scenario Selection for Seismic Slope Stability Assessment

2020 ◽  
Vol 12 (12) ◽  
pp. 4977
Author(s):  
Alexey Konovalov ◽  
Yuriy Gensiorovskiy ◽  
Andrey Stepnov
Keyword(s):  
Slope Stability ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Slope Failure ◽  
Probabilistic Approach ◽  
Seismic Loading ◽  
Time Interval ◽  
Total Probability ◽  
Ground Shaking ◽  
Earthquake Scenario

Design ground shaking intensity, based on probabilistic seismic hazard analysis (PSHA) maps, is most commonly used as a triggering condition to analyze slope stability under seismic loading. Uncertainties that are associated with expected ground motion levels are often ignored. This study considers an improved, fully probabilistic approach for earthquake scenario selection. The given method suggests the determination of the occurrence probability of various ground motion levels and the probability of landsliding for these ground motion parameters, giving the total probability of slope failure under seismic loading in a certain time interval. The occurrence hazard deaggregation technique is proposed for the selection of the ground shaking level, as well as the magnitude and source-to-site distance of a design earthquake, as these factors most probably trigger slope failure within the time interval of interest. An example application of the approach is provided for a slope near the highway in the south of Sakhalin Island (Russia). The total probability of earthquake-induced slope failure in the next 50 years was computed to be in the order of 16%. The scenario peak ground acceleration value estimated from the disaggregated earthquake-induced landslide hazard is 0.15g, while the 475-year seismic hazard curve predicts 0.3g. The case study highlights the significant difference between ground shaking scenario levels in terms of the 475-year seismic hazard map and the considered fully probabilistic approach.

Ground motion prediction equations for Arias Intensity using the Kik-net database

2020 ◽  
pp. 875529302093881
Author(s):  
Mahdi Bahrampouri ◽  
Adrian Rodriguez-Marek ◽  
Russell A Green
Keyword(s):  
Ground Motion ◽  
Slope Failure ◽  
Energy Content ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Arias Intensity ◽  
Intensity Measures ◽  
Earthquake Scenario

In seismic design, intensity measures are selected on the basis of how well these parameters correlate with the damage caused by earthquakes and on our ability to predict these intensity measures for a given earthquake scenario. As an index for the energy content of ground motions, Arias Intensity has proved to be efficient in several applications, including the prediction of earthquake-induced slope failure and damage in structures, and to a lesser extent liquefaction triggering. In this article, the Kiban-Kyoshin network (KiK)-net database is used to present ground motion prediction equations (GMPEs) for Arias Intensity of shallow crustal and subduction zone earthquakes. The proposed GMPEs are applicable for M 4-9. The predictive models incorporate the average shear-wave velocity over the upper 30 meters (VS30) for the prediction of site effects. The proposed relationships include additional attenuation for paths that cross the volcanic fronts and different attenuation for forearc and backarc regions of Japan.

Probabilistic Seismic Hazard Analyses for Ground Motions and Fault Displacement at Yucca Mountain, Nevada

2001 ◽  
Vol 17 (1) ◽  
pp. 113-151 ◽  
Author(s):  
◽  
J. Carl Stepp ◽  
Ivan Wong ◽  
John Whitney ◽  
Richard Quittmeyer ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Spent Nuclear Fuel ◽  
Epistemic Uncertainty ◽  
Yucca Mountain ◽  
Expert Elicitation ◽  
Probabilistic Seismic Hazard ◽  
Geologic Repository ◽  
Ground Shaking ◽  
Fault Displacement

Probabilistic seismic hazard analyses were conducted to estimate both ground motion and fault displacement hazards at the potential geologic repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. The study is believed to be the largest and most comprehensive analyses ever conducted for ground-shaking hazard and is a first-of-a-kind assessment of probabilistic fault displacement hazard. The major emphasis of the study was on the quantification of epistemic uncertainty. Six teams of three experts performed seismic source and fault displacement evaluations, and seven individual experts provided ground motion evaluations. State-of-the-practice expert elicitation processes involving structured workshops, consensus identification of parameters and issues to be evaluated, common sharing of data and information, and open exchanges about the basis for preliminary interpretations were implemented. Ground-shaking hazard was computed for a hypothetical rock outcrop at -300 m, the depth of the potential waste emplacement drifts, at the designated design annual exceedance probabilities of 10-3 and 10-4. The fault displacement hazard was calculated at the design annual exceedance probabilities of 10-4 and 10-5.

scholarly journals Large deformation dynamic analysis of progressive failure in layered clayey slopes under seismic loading using the particle finite element method

2021 ◽  
Author(s):  
Liang Wang ◽  
Xue Zhang ◽  
Stefano Tinti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Slope Failure ◽  
Failure Modes ◽  
Slip Surface ◽  
Seismic Loading ◽  
Time Interval ◽  
Particle Finite Element Method ◽  
Layered Slope ◽  
Element Method

AbstractThis paper presents the failure analysis of layered clayey slopes with emphasis on the combined effect of the clay’s weakening behavior and the seismic loading using the particle finite element method (PFEM). Diverse failure mechanisms have been disclosed via the PFEM modelling when the strain-weakening behavior of clay is concerned. In contrast to a single layered slope exhibiting either a shallow or a deep failure mode, a layered slope may undergo both failure modes with a time interval in between. Seismic loadings also enlarge the scale of slope failure in clays with weakening behavior. The failure of a real layered slope (i.e. the 1988 Saint-Adelphe landslide, Canada) triggered by the Saguenay earthquake is also studied in this paper. The simulation results reveal that the choice of the strain-softening value controls the slip surface of the landslide and the amplification effect is important in the triggering of the landslide.

scholarly journals Ground motion simulations for finite-fault earthquake scenarios on the Húsavík-Flatey Fault, North Iceland

2021 ◽  
Author(s):  
Claudia Abril ◽  
Martin Mai ◽  
Benedikt Halldórsson ◽  
Bo Li ◽  
Alice Gabriel ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Large Scale ◽  
Velocity Model ◽  
Fault System ◽  
Fault Rupture ◽  
Ground Shaking ◽  
Earthquake Scenarios ◽  
3D Velocity Model ◽  
Finite Fault

<p>The Tjörnes Fracture Zone (TFZ) in North Iceland is the largest and most complex zone of transform faulting in Iceland, formed due to a ridge-jump between two spreading centers of the Mid-Atlantic Ridge, the Northern Volcanic Zone and Kolbeinsey Ridge in North Iceland. Strong earthquakes (Ms>6) have repeatedly occurred in the TFZ and affected the North Icelandic population. In particular the large historical earthquakes of 1755 (Ms 7.0) and 1872 (doublet, Ms 6.5), have been associated with the Húsavı́k-Flatey Fault (HFF), which is the largest linear strike-slip transform fault in the TFZ, and in Iceland. We simulate fault rupture on the HFF and the corresponding near-fault ground motion for several potential earthquake scenarios, including scenario events that replicate the large 1755 and 1872 events. Such simulations are relevant for the town of Húsavı́k in particular, as it is located on top of the HFF and is therefore subject to the highest seismic hazard in the country. Due to the mostly offshore location of the HFF, its precise geometry has only recently been studied in more detail. We compile updated seismological and geophysical information in the area, such as a recently derived three-dimensional velocity model for P and S waves. Seismicity relocations using this velocity model, together with bathymetric and geodetic data, provide detailed information to constrain the fault geometry. In addition, we use this 3D velocity model to simulate seismic wave propagation. For this purpose, we generate a variety of kinematic earthquake-rupture scenarios, and apply a 3D finite-difference method (SORD) to propagate the radiated seismic waves through Earth structure. Slip distributions for the different scenarios are computed using a von Karman autocorrelation function whose parameters are calibrated with slip distributions available for a few recent Icelandic earthquakes. Simulated scenarios provide synthetic ground motion and time histories and estimates of peak ground motion parameters (PGA and PGV) at low frequencies (<2 Hz) for Húsavík and other main towns in North Iceland along with maps of ground shaking for the entire region [130 km x 110 km]. Ground motion estimates are compared with those provided by empirical ground motion models calibrated to Icelandic earthquakes and dynamic fault-rupture simulations for the HFF. Directivity effects towards or away from the coastal areas are analyzed to estimate the expected range of shaking. Thick sedimentary deposits (up to ∼4 km thick) located offshore on top of the HFF (reported by seismic, gravity anomaly and tomographic studies) may affect the effective depth of the fault's top boundary and the surface rupture potential. The results of this study showcase the extent of expected ground motions from significant and likely earthquake scenarios on the HFF. Finite fault earthquake simulations complement the currently available information on seismic hazard for North Iceland, and are a first step towards a systematic and large-scale earthquake scenario database on the HFF, and for the entire fault system of the TFZ, that will enable comprehensive and physics-based hazard assessment in the region.</p>

scholarly journals Probabilistic assessment of seismic-induced slope displacements: an application in Italy

2021 ◽  
Author(s):  
Fabio Rollo ◽  
Sebastiano Rampello
Keyword(s):  
Ground Motion ◽  
Seismic Performance ◽  
Ground Motions ◽  
Regional Scale ◽  
Probabilistic Approach ◽  
Landslide Hazard ◽  
Slope Instability ◽  
Hazard Maps ◽  
Ground Shaking ◽  
Seismic Landslide

AbstractEarthquake-induced slope instability is one of the most important hazards related to ground shaking, causing damages to the environment and, often, casualties. Therefore, it is important to assess the seismic performance of slopes, especially in the near fault regions, evaluating the permanent displacements induced by seismic loading. This paper applies a probabilistic approach to evaluate the seismic performance of slopes using an updated database of ground motions recorded during the earthquakes occurred in Italy. The main advantage of this approach is that of accounting for the aleatory variability of both ground motions and prediction of seismic-induced displacements of slopes. The results are presented in terms of hazard curves, showing the annual rate of exceedance of permanent slope displacement evaluated using ground motion data provided by a standard probabilistic hazard analysis and a series of semi-empirical relationships linking the permanent displacements of slopes to one or more ground motion parameters. The procedure has been implemented on a regional scale to produce seismic landslide hazard maps for the Irpinia district, in Southern Italy, characterised by a severe seismic hazard. Seismic landslide hazard maps represent a useful tool for practitioners and government agencies for a regional planning to identify and monitor zones that are potentially susceptible to earthquake-induced slope instability, thus requiring further detailed, site-specific studies.

Do PSHA maps overpredict or are there shaking deficits in the historic record?

2021 ◽  
Author(s):  
Leah Salditch ◽  
Seth Stein
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Performance Metrics ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Ground Shaking ◽  
Intensity Mapping ◽  
Time Period ◽  
Probabilistic Forecasts ◽  
The Difference

<p>Probabilistic Seismic Hazard Assessment (PSHA) attempts to forecast the fraction of sites on a hazard map where ground shaking will exceed the mapped value within some time period. Because the maps are probabilistic forecasts, they explicitly assume that shaking will exceed the mapped value some of the time. At a point on a PSHA map, the probability p that during t years of observations shaking will exceed the value on a map with a T-year return period is assumed to be described by the exponential cumulative density function: p = 1 – exp(-t/T). The fraction of sites, f, where observed shaking exceeds the mapped value should behave the same way. To assess the 2018 USGS National Seismic Hazard Model maps for California, we created the California Historical Intensity Mapping Project (CHIMP), a 162-yr long dataset that combines and consistently reinterprets seismic intensity information that has been stored in disparate and sometimes hard-to-access locations (Salditch et al., 2020). We use two performance metrics; M0 based on the fraction of sites where modeled ground motion is exceeded, and M1 based on of the difference between the mapped and observed ground motion at all sites. M0 is implicit in PSHA because it measures the difference between the predicted and observed fraction of site exceedances and is therefore a key indicator of map performance.</p><p>We explore these metrics for CHIMP. Assuming the dataset to be correct, it appears that the hazard maps overpredicted shaking even correcting for the time period involved. Assuming the model is also correct, a shaking deficit exists between the model and observations. Possible reasons for this apparent overprediction/shaking deficit include: 1) the observations in CHIMP are biased low; 2) the observation period has been less seismically active than typical – either by chance or temporal variability due to stress shadow effects; 3) the model overpredicts due to either the earthquake rupture forecast or the ground motion models. Similar overpredictions appear for past shaking data in Italy, Japan, and Nepal, implying that seismic hazards are often overestimated. Whether this reflects too-high models and/or biased data remains an important question.</p>

A probabilistic approach to ground-motion selection for engineering design

1995 ◽  
Vol 85 (3) ◽  
pp. 937-942
Author(s):  
Martin C. Chapman
Keyword(s):  
Time Series ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Response Spectrum ◽  
Probabilistic Approach ◽  
Data Set ◽  
Motion Time ◽  
Wide Range ◽  
Hazard Level

Abstract The solutions of many earthquake engineering problems involve dynamic analyses using ground-motion time series. It is often desirable to base the selection of such motions on a probabilistic estimate of the seismic hazard. The hazard density function evaluated at a chosen hazard level provides the information necessary to determine objectively the most likely earthquake events, defined by magnitude and distance, that contribute to seismic hazard. For a wide range of hazard models it is possible to show that the difference between the median motion at a site, given the occurrence of the most likely event, and the motion value corresponding to a specified hazard level, is due entirely to the modeling of random error in the strong-motion data set. This points to a straightforward approach to selecting ground-motion recordings that represent the most likely time-domain realizations of the hazard model for a given motion parameter and hazard level. Ground-motion time series selection and/or synthesis based upon this approach, for various frequency bands of the response spectrum, can provide an optimum basis for seismic design.

scholarly journals Estimation of seismic ground motions using deterministic approach for major cities of Gujarat

2012 ◽  
Vol 12 (6) ◽  
pp. 2019-2037 ◽  
Author(s):  
J. Shukla ◽  
D. Choudhury
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Probabilistic Approach ◽  
Maximum Magnitude ◽  
Deterministic Approach ◽  
Major City ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Ground Motion Attenuation ◽  
Instrumental Records

Abstract. A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA) and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs) of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b-value, maximum magnitude and ground motion attenuation relations (GMARs). The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002) to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the Kachchh region i.e. Bhuj city and moderate in the Mainland Gujarat, i.e. cities of Surat and Ahmedabad. The seismic ground motion level in the Saurashtra is moderate but marginally differs from that as presently specified in IS:1893-Part I (2002). Based on the present study, the recommended PGA values for the cities studied are 0.13 g, 0.15 g, 0.64 g, 0.14 g and 0.2 g for Ahmedabad city, Surat City, Bhuj City, Jamnagar City and Junagadh city, respectively. The prepared spectra can be further used for seismic resistant design of structures within the above major city boundaries of Gujarat to quantify seismic loading on structures.

scholarly journals A probabilistic seismic hazard assessment for Greece and the surrounding region including site-specific considerations

2009 ◽  
Vol 47 (6) ◽  
Author(s):  
T. M. Tsapanos ◽  
P. Mäntyniemi ◽  
A. Kijko
Keyword(s):  
Seismic Hazard ◽  
Probabilistic Approach ◽  
Region Of Interest ◽  
Seismic Hazard Assessment ◽  
Soil Conditions ◽  
Probabilistic Seismic Hazard Assessment ◽  
Time Interval ◽  
Ground Acceleration ◽  
Design Earthquake ◽  
Seismic Hazard Map

A probabilistic approach was applied to map the seismic hazard in Greece and the surrounding region. The procedure does not require any specification of seismic sources or/and seismic zones and allows for the use of the whole seismological record, comprising both historical and instrumental data, available for the region of interest. The new seismic hazard map prepared for Greece and its vicinity specifies a 10% probability of exceedance of the given Peak Ground Acceleration (PGA) values for shallow seismicity and intermediate soil conditions for an exposure time of 50 years. When preparing the map, the new PGA attenuation relation given by Margaris et al. (2001) was employed. The new map shows a spatial distribution of the seismic hazard that corresponds well with the features of shallow seismicity within the examined region. It depicts the level of seismic hazard in which the exceedance of the PGA value of 0.25 g may be expected to occur within limited areas. The highest estimated levels of seismic hazard inside the territory of Greece are found in the Northern Sporades Islands, where PGA values in excess of 0.50 g are reached at individual sites, and in the Zante Island in Western Greece, where PGA values in the range of 0.35 g to 0.40 g are obtained at more numerous localities. High values are also observed in the sea between the Karpathos and Rhodes islands, near the Island of Amorgos (Cyclades Archipelago) and in the Southwestern Peloponnesus. The levels of seismic hazard at the sites of seven Greek cities (Athens, Jannena, Kalamata, Kozani, Larisa, Rhodes and Thessaloniki) were also estimated in terms of probabilities that a given PGA value will be exceeded at least once during a time interval of 1, 50 and 100 years at those sites. These probabilities were based on the maximum horizontal PGA values obtained by applying the design earthquake procedure, and the respective median values obtained were 0.24 g for Athens, 0.28 g for Jannena, 0.30 g for Kalamata, 0.21 g for Kozani, 0.24 g for Larisa, 0.43 g for Rhodes and 0.35 g for Thessaloniki. The probabilities of exceedance of the estimated maximum possible PGA value were also calculated for the cities to illustrate the uncertainty of maximum PGA assessment.

scholarly journals Probabilistic seismic hazard maps from seismicity patterns analysis: the Iberian Peninsula case

2004 ◽  
Vol 4 (3) ◽  
pp. 407-416 ◽  
Author(s):  
A. Jiménez ◽  
A. M. Posadas ◽  
T. Hirata ◽  
J. M. García
Keyword(s):  
Seismic Hazard ◽  
Cellular Automaton ◽  
Iberian Peninsula ◽  
Probabilistic Approach ◽  
Energy Criterion ◽  
Automata Theory ◽  
Time Interval ◽  
Probabilistic Seismic Hazard ◽  
Data Set ◽  
A Cell

Abstract. Earthquake prediction is a main topic in Seismology. Here, the goal is to know the correlation between the seismicity at a certain place at a given time with the seismicity at the same place, but at a following interval of time. There are no ways for exact predictions, but one can wonder about the causality relations between the seismic characteristics at a given time interval and another in a region. In this paper, a new approach to this kind of studies is presented. Tools which include cellular automata theory and Shannon's entropy are used. First, the catalogue is divided into time intervals, and the region into cells. The activity or inactivity of each cell at a certain time is described using an energy criterion; thus a pattern which evolves over time is given. The aim is to find the rules of the stochastic cellular automaton which best fits the evolution of the pattern. The neighborhood utilized is the cross template (CT). A grid search is made to choose the best model, being the mutual information between the different times the function to be maximized. This function depends on the size of the cells β on and the interval of time τ which is considered for studying the activity of a cell. With these β and τ, a set of probabilities which characterizes the evolution rules is calculated, giving a probabilistic approach to the spatiotemporal evolution of the region. The sample catalogue for the Iberian Peninsula covers since 1970 till 2001. The results point out that the seismic activity must be deduced not only from the past activity at the same region but also from its surrounding activity. The time and spatial highest interaction for the catalogue used are of around 3.3 years and 290x165 km2, respectively; if a cell is inactive, it will continue inactive with a high probability; an active cell has around the 60% probability of continuing active in the future. The Probabilistic Seismic Hazard Map obtained marks the main seismic active areas (northwestern Africa) were the real seismicity has been occurred after the date of the data set studied. Also, the Hurst exponent has been studied. The value calculated is 0.48±0.02, which means that the process is inherently unpredictable. This result can be related to the incapacity of the cellular automaton obtained of predicting sudden changes.

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