Earthquake Recurrence Model for the Colombia–Ecuador Subduction Zone Constrained from Seismic and Geodetic Data, Implication for PSHA

2021 ◽  
Author(s):  
Judith Mariniere ◽  
Céline Beauval ◽  
Jean-Mathieu Nocquet ◽  
Mohamed Chlieh ◽  
Hugo Yepes
Keyword(s):  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Geodetic Data ◽  
Probabilistic Seismic Hazard Assessment ◽  
Maximum Magnitude ◽  
Earthquake Recurrence ◽  
Uniform Hazard Spectra ◽  
Deficit Accumulation ◽  
Seismicity Rates ◽  
Recurrence Model

ABSTRACT Probabilistic seismic hazard assessment relies on long-term earthquake forecasts and ground-motion models. Our aim is to improve earthquake forecasts by including information derived from geodetic measurements, with an application to the Colombia–Ecuador megathrust. The annual rate of moment deficit accumulation at the interface is quantified from geodetically based interseismic coupling models. We look for Gutenberg–Richter recurrence models that match both past seismicity rates and the geodetic moment deficit rate, by adjusting the maximum magnitude. We explore the uncertainties on the seismic rates (a- and b-values, shape close to Mmax) and on the geodetic moment deficit rate to be released seismically. A distribution for the maximum magnitude Mmax bounding a series of earthquake recurrence models is obtained for the Colombia–Ecuador megathrust. Models associated with Mmax values compatible with the extension of the interface segment are selected. We show that the uncertainties mostly influencing the moment-balanced recurrence model are the fraction of geodetic moment released through aseismic processes and the form of the Gutenberg–Richter model close to Mmax. We combine the computed moment-balanced recurrence models with a ground-motion model, to obtain a series of uniform hazard spectra representative of uncertainties at one site on the coast. Considering the recent availability of a massive quantity of geodetic data, our approach could be used in other well-instrumented regions of the world.

scholarly journals Planar Seismic Source Characterization Models Developed for Probabilistic Seismic Hazard Assessment of Istanbul

2017 ◽  
Author(s):  
Zeynep Gülerce ◽  
Kadir Buğra Soyman ◽  
Barış Güner ◽  
Nuretdin Kaymakci
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Probabilistic Seismic Hazard Assessment ◽  
Model Parameters ◽  
Probabilistic Seismic Hazard ◽  
Maximum Magnitude ◽  
Source Characterization ◽  
Seismicity Rates

Abstract. This contribution provides an updated planar seismic source characterization (SSC) model to be used in the probabilistic seismic hazard assessment (PSHA) for Istanbul. It defines planar rupture systems for the four main segments of North Anatolian Fault Zone (NAFZ) that are critical for the PSHA of Istanbul: segments covering the rupture zones of 1999 Kocaeli and Düzce earthquakes, Central Marmara, and Ganos/Saros segments. In each rupture system, the source geometry is defined in terms of fault length, fault width, fault plane attitude, and segmentation points. Activity rates and the magnitude recurrence models for each rupture system are established by considering geological and geodetic constraints and are tested based on the observed seismicity that associated with the rupture system. Uncertainty in the SSC model parameters (e.g. b-value, maximum magnitude, weights of the rupture scenarios) is considered in the logic tree. To acknowledge the effect of earthquakes that are not associated with the defined rupture systems on the hazard, a background zone is introduced and the seismicity rates in the background zone are calculated using smoothed-seismicity approach. The state-of-the-art SSC model presented here is the first fully-documented and ready-to-use fault-based SSC model developed for the PSHA of Istanbul.

scholarly journals Planar seismic source characterization models developed for probabilistic seismic hazard assessment of Istanbul

2017 ◽  
Vol 17 (12) ◽  
pp. 2365-2381 ◽  
Author(s):  
Zeynep Gülerce ◽  
Kadir Buğra Soyman ◽  
Barış Güner ◽  
Nuretdin Kaymakci
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Probabilistic Seismic Hazard Assessment ◽  
Model Parameters ◽  
Probabilistic Seismic Hazard ◽  
Maximum Magnitude ◽  
Source Characterization ◽  
Seismicity Rates

Abstract. This contribution provides an updated planar seismic source characterization (SSC) model to be used in the probabilistic seismic hazard assessment (PSHA) for Istanbul. It defines planar rupture systems for the four main segments of the North Anatolian fault zone (NAFZ) that are critical for the PSHA of Istanbul: segments covering the rupture zones of the 1999 Kocaeli and Düzce earthquakes, central Marmara, and Ganos/Saros segments. In each rupture system, the source geometry is defined in terms of fault length, fault width, fault plane attitude, and segmentation points. Activity rates and the magnitude recurrence models for each rupture system are established by considering geological and geodetic constraints and are tested based on the observed seismicity that is associated with the rupture system. Uncertainty in the SSC model parameters (e.g., b value, maximum magnitude, slip rate, weights of the rupture scenarios) is considered, whereas the uncertainty in the fault geometry is not included in the logic tree. To acknowledge the effect of earthquakes that are not associated with the defined rupture systems on the hazard, a background zone is introduced and the seismicity rates in the background zone are calculated using smoothed-seismicity approach. The state-of-the-art SSC model presented here is the first fully documented and ready-to-use fault-based SSC model developed for the PSHA of Istanbul.

scholarly journals Updated Probabilistic Seismic Hazard Assessment of Pakistan

2021 ◽  
Author(s):  
Muhammad Waseem ◽  
Mustafa Erdik
Keyword(s):  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Motion Prediction ◽  
Probabilistic Seismic Hazard Assessment ◽  
Maximum Magnitude ◽  
Spectral Acceleration ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Logic Tree ◽  
Probability Of Exceedance

Abstract Probabilistic seismic hazard assessment of Pakistan is carried out to compute hazard in terms of peak ground acceleration (PGA) and spectral acceleration (SA) for 975 and 2475 years return periods. A composite earthquake catalogue consisting of 32,700 events has been compiled having a magnitude range of Mw 4.0-8.2 in this study and used in the analysis to make computations at a rectangular grid of 5 km in the OpenQuake plateform. Ground motion values have been obtained for flat rock reference seismic site conditions with shear wave velocity of 760 m/s. The epistemic uncertainties inherent in ground motion prediction equations and maximum magnitude potential of seismic sources are taken into account through logic tree. Ground motion prediction equations are assigned equal weights in the logic tree while different various weight are assigned to the maximum magnitude potential models. Results of the study are expressed as ground motion contour maps, mean uniform hazard spectra for important cities in Pakistan. PGA ranges from 0.16 to 0.54g for 10 % of probability of exceedance, 0.23 to 0.72g of probability of exceedance 0.32 to 1.02 g for 2 % of probability of exceedance in 50 years. Spectral acceleration at 0.2 s range from 0.67 to 2.19g for 2% chance of exceedance in 50 years, respectively. While spectral acceleration at 1.0 s values range from 0.09 to 0.52g 2% chance of exceedance in 50 years. Comparison of results of this study with other well regarded references of suggest that results of the study are rational and are reliable.

Probabilistic seismic hazard assessment for Taiwan: TEM PSHA2020

2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 137-159
Author(s):  
Chung-Han Chan ◽  
Kuo-Fong Ma ◽  
J Bruce H Shyu ◽  
Ya-Ting Lee ◽  
Yu-Ju Wang ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Site Amplification ◽  
Motion Prediction ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Seismogenic Structure

The Taiwan Earthquake Model (TEM) published the first version of the Taiwan probabilistic seismic hazard assessment (named TEM PSHA2015) 5 years ago. For updating to the TEM PSHA2020, we considered an updated seismogenic structure database, including the structures newly identified with 3D geometry, an earthquake catalog made current to 2016, state-of-the-art seismic models, a new set of ground motion prediction equations, and site amplification factors. In addition to earthquakes taking place on each individual seismogenic structure, the updated seismic model included the possibility of an earthquake occurring on multiple structures. To include fault memory for illustrating activity on seismogenic structure sources, we incorporated the Brownian passage time model. For the crustal seismicity that cannot be attributed to any specific structure, we implemented both area source and smoothing kernel models. A new set of ground motion prediction equations is incorporated. In addition to the calculation of hazard at engineering bedrock, our assessment included site amplification factors that competent authorities of governments and private companies could use to implement hazard prevention and reduction strategies.

From Ergodic to Region- and Site-Specific Probabilistic Seismic Hazard Assessment: Method Development and Application at European and Middle Eastern Sites

2017 ◽  
Vol 33 (4) ◽  
pp. 1433-1453 ◽  
Author(s):  
Sreeram Reddy Kotha ◽  
Dino Bindi ◽  
Fabrice Cotton
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Method Development ◽  
Site Response ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Site Specific ◽  
Aleatory Variability

The increasing numbers of recordings at individual sites allows quantification of empirical linear site-response adjustment factors ( δS2 S s) from the ground motion prediction equation (GMPE) residuals. The δS2 S s are then used to linearly scale the ergodic GMPE predictions to obtain site-specific ground motion predictions in a partially non-ergodic Probabilistic Seismic Hazard Assessment (PSHA). To address key statistical and conceptual issues in the current practice, we introduce a novel empirical region- and site-specific PSHA methodology wherein, (1) site-to-site variability ( φ S2 S) is first estimated as a random-variance in a mixed-effects GMPE regression, (2) δS2 S s at new sites with strong motion are estimated using the a priori φ S2 S, and (3) the GMPE site-specific single-site aleatory variability σ ss,s is replaced with a generic site-corrected aleatory variability σ0. Comparison of region- and site-specific hazard curves from our method against the traditional ergodic estimates at 225 sites in Europe and Middle East shows an approximate 50% difference in predicted ground motions over a range of hazard levels—a strong motivation to increase seismological monitoring of critical facilities and enrich regional ground motion data sets.

scholarly journals Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe

2012 ◽  
Vol 16 (3) ◽  
pp. 451-473 ◽  
Author(s):  
Elise Delavaud ◽  
Fabrice Cotton ◽  
Sinan Akkar ◽  
Frank Scherbaum ◽  
Laurentiu Danciu ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Logic Tree

scholarly journals Seismic hazard for the Trans Adriatic Pipeline (TAP). Part 2: broadband scenarios at the Fier Compressor Station (Albania)

2021 ◽  
Author(s):  
L. Moratto ◽  
A. Vuan ◽  
A. Saraò ◽  
D. Slejko ◽  
C. Papazachos ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Transfer Functions ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Compressor Station ◽  
Damage Functions ◽  
Worst Case

AbstractTo ensure environmental and public safety, critical facilities require rigorous seismic hazard analysis to define seismic input for their design. We consider the case of the Trans Adriatic Pipeline (TAP), which is a pipeline that transports natural gas from the Caspian Sea to southern Italy, crossing active faults and areas characterized by high seismicity levels. For this pipeline, we develop a Probabilistic Seismic Hazard Assessment (PSHA) for the broader area, and, for the selected critical sites, we perform deterministic seismic hazard assessment (DSHA), by calculating shaking scenarios that account for the physics of the source, propagation, and site effects. This paper presents a DSHA for a compressor station located at Fier, along the Albanian coastal region. Considering the location of the most hazardous faults in the study site, revealed by the PSHA disaggregation, we model the ground motion for two different scenarios to simulate the worst-case scenario for this compressor station. We compute broadband waveforms for receivers on soft soils by applying specific transfer functions estimated from the available geotechnical data for the Fier area. The simulations reproduce the variability observed in the ground motion recorded in the near-earthquake source. The vertical ground motion is strong for receivers placed above the rupture areas and should not be ignored in seismic designs; furthermore, our vertical simulations reproduce the displacement and the static offset of the ground motion highlighted in recent studies. This observation confirms the importance of the DSHA analysis in defining the expected pipeline damage functions and permanent soil deformations.

scholarly journals Probabilistic seismic hazard assessment of Bishkek, Kyrgyzstan, considering empirically estimated site effects

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Shahid Ullah ◽  
Dino Bindi ◽  
Marco Pilz ◽  
Stefano Parolai
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Site Effects ◽  
Response Spectrum ◽  
Seismic Hazard Assessment ◽  
Geological Structure ◽  
Probabilistic Seismic Hazard Assessment ◽  
Site Classification ◽  
Ground Acceleration

<p>It is well known that variability in the surface geology potentially leads to the modification of earthquake-induced ground motion over short distances. Although this effect is of major importance when seismic hazard is assessed at the urban level, it is very often not appropriately accounted for. In this paper, we present a first attempt at taking into account the influence of the shallow geological structure on the seismic hazard assessment for Bishkek, Kyrgyzstan, using a proxy (Vs30) that has been estimated from in situ seismic noise array analyses, and considering response spectral ratios calculated by analyzing a series of earthquake recordings of a temporary seismic network. To highlight the spatial variability of the observed ground motion, the obtained results are compared with those estimated assuming a homogeneous Vs30 value over the whole urban area. The seismic hazard is evaluated in terms of peak ground acceleration (PGA) and spectral acceleration (SA) at different periods (frequencies). The presented results consider the values obtained for a 10% probability of exceedance in 50 years. The largest SA estimated considering a rock site classification of the area (0.43 g) is observed for a period of 0.1 s (10 Hz), while the maximum PGA reaches 0.21 g. When site effects are included through the Vs30 proxy in the seismic hazard calculation, the largest SA, 0.67 g, is obtained for a period of 0.3 s (about 3.3 Hz). In terms of PGA, in this case the largest estimated value reaches 0.31 g in the northern part of the town. When the variability of ground motion is accounted for through response spectrum ratios, the largest SA reaches a value as high as 1.39 g at a period of 0.5 s. In general, considering site effects in the seismic hazard assessment of Bishkek leads to an increase of seismic hazard in the north of the city, which is thus identified as the most hazardous part within the study area and which is more far away from the faults.</p>

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