Deterministic Seismic Hazard Assessment Research Articles

Deterministic seismic hazard assessment of a long mountainous road tunnel: a case study of Lowari Tunnel, Pakistan

Deterministic seismic hazard assessment of a long mountainous road tunnel: a case study of Lowari Tunnel, Pakistan

Unveiling earthquake hazard in Noida, India: a combined probabilistic and deterministic seismic hazard assessment

Unveiling earthquake hazard in Noida, India: a combined probabilistic and deterministic seismic hazard assessment

Unravelling Karachi’s Seismic Potential: Estimating Maximum Ground Shaking in Various Zones

Karachi, a sprawling city spanning over 3500[Formula: see text]sq. km, exhibits significant variability in seismic hazard across its expanse. This study employs a deterministic approach for seismic hazard assessment due to the unavailability of a long-term seismic archive required for a probabilistic approach, given the city’s relatively young age. Furthermore, a novel methodology is employed in this study, utilizing all known faults within Karachi’s seismic vicinity for conducting Deterministic Seismic Hazard Assessment (DSHA). Individual hazards associated with each seismic source are estimated, enabling the determination of the most severe hazard for the development of a seismic zoning map. The resulting DSHA-based seismic hazard assessment categorizes Karachi into four seismic zones, ranging from Zone 2A to Zone 4. This paper concludes that for a vast city like Karachi, relying solely on a single fault source for DSHA does not accurately represent the realistic seismic hazard to the region.

Seismic roulette: Hazards and risks

AbstractThe Neo Deterministic Seismic Hazard Assessment (NDSHA) is the innovative multi‐disciplinary scenario‐physics‐based approach for the evaluation of seismic hazard and risks. When an earthquake occurs, the ground shaking does not depend on its likelihood according to the widespread Probabilistic Seismic Hazard Analysis (PSHA), which estimates are too often wrong. An “unlikely” earthquake can occur at any time and, sooner or later, with 100% probability. Therefore, from a perspective of safety, it is essential that infrastructure and public installations are designed so as to resist future strong earthquakes. NDSHA has proven to both reliably and realistically simulate comprehensive sets of hazardous ground motions in many regions worldwide. Today NDSHA is gaining momentum in spreading worldwide an innovative Paradigm of Reliable Seismic Hazard Assessment (RSHA) that should ultimately change mind‐sets of scientific and engineering communities from disbelief in probabilistic forecasting to optimistic challenging issues of neo‐deterministic predictability of Natural Hazards and Risks.

A deterministic seismic risk macrozonation of Seville

The seismicity of the southwestern Iberian Peninsula is moderate but large events with long return periods occur (≈ 200 years). This exceeds the life of various generations, making the population unacquainted with the seismic hazard. On the one hand, this results in a low demanding seismic code which increases the seismic vulnerability and, therefore, the seismic risk. On the other hand, the local emergency services must be properly prepared to face a destructive seismic event, with emergency plans and mitigation strategies. This assumption enhances the need of assessing the seismic risk of Seville in a civil protection context. For all the aforementioned and for the lack of instrumental data of relevant earthquakes, the assessment of the seismic hazard in this area is challenging. To do this, seismogenic zones of the new seismic hazard map of Spain have been used as sources. The peak ground acceleration (PGA) for each scenario has been calculated by means of ground motion prediction equations (GMPE). To estimate the site effects, in a 1D model environment, a shear wave velocity (Vs) map of the top 5 m has been depicted based on the standard penetration test (SPT). Seville’s building stock has been classified in agreement with the previous works in Lorca and Barcelona to determine its vulnerability. The main goal of this work was to investigate the influence of the soil amplification on the seismic behaviour of different building typologies. Therefore, the final target was to plot the damage scenarios expected in Seville under a maximum credible earthquake by means of a deterministic seismic hazard assessment (DSHA). As outputs, the scenario modelled showed that around 27 000 buildings would experience a moderate damage and that 26 000 would suffer pre-collapse or even collapse. Thus, approximately 10% of the population would lose their dwellings. Regarding the human loses, around 22 000 people would suffer serious injuries and approximately 5 000 people would die. Owing to these conclusions, this research evidences the crucial need by civil protection services to implement a local emergency plan as a tool to mitigate the probable consequences that arise from this threat.

Neo-deterministic seismic hazard assessment of Corsica-Sardinia block

The Corsica-Sardinia lithospheric block is commonly considered as a region of very low seismicity and the scarce reported seismicity for the area has till now precluded the reliable assessment of its seismic hazard. The time-honored assumption has been recently questioned and the historical seismicity of Sardinia has been reevaluated. Even more, several seismogenic nodes capable of M5 + have been recognized in the Corsica-Sardinia block exploiting the morphostructural zonation technique, calibrated to earlier results obtained for the Iberian peninsula, which has structural lithospheric affinities with the Corsica-Sardinia block. All this allows now for the computation of reliable earthquake hazard maps at bedrock conditions exploiting the power of Neo Deterministic Seismic Hazard Assessment (NDSHA) evaluation. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures and generates realistic time series from which several earthquake ground motion parameters can be readily extracted. NDSHA exploits in an optimized way all the available knowledge about lithospheric mechanical parameters, seismic history, seismogenic zones and nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved computing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. The way to this approach has been open by studies focused on continental Italy and Sicily, where the agreement between hazard maps obtained using seismogenic zones, informed by earthquake catalog data, and the maps obtained using only seismogenic nodes are very good.

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

To 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.

Bayesian inference of a physical seismological model for earthquake strong-motion in south Iceland

Earthquake ground motion prediction in Iceland where strong-motion data is scarce poses a challenge as empirical ground motion models (GMM) developed from data in other regions systematically fail to capture the consistently large near-fault peak amplitudes and their rapid attenuation with distance from the earthquake source. Therefore, regional GMMs must be constructed but due to the limited data, and none above Mw6.5, earthquake source scaling is unconstrained at larger magnitudes. Instead, physics-based GMMs should be applied based on realistic earthquake source modeling. For that purpose, a seismological model constructed around the specific barrier model (SBM) has been calibrated in the context of the stochastic method using random vibration theory, to earthquake high-frequency strong-motions in the South Iceland Seismic Zone. The SBM is used as it provides a physically consistent and efficient description of the heterogeneous faulting processes that are responsible for the generation of high-frequency waves. On the basis of the concise point-source representation of radiated spectra from N subevents of the SBM the pseudo-spectral accelerations were modeled and compared with that of data in the spectral domain. Backwards model selection was then carried out using Bayesian inference with Monte Carlo simulations and Markov Chains. The number of parameters in the model inference was reduced to obtain stable Markov chains and posterior probability density functions for each parameter, eliminating parametric cross-correlations to the extent possible. The seismological model has been shown to be unbiased with respect to strong-motions in the SISZ, with a total standard deviation of 0.216 (common logarithm), with only a minor contribution from inter-event variability, suggesting a relatively uniform character of SISZ earthquake strong-motions. We showcase the application of the SBM extended into a finite-fault and model the three Mw6.3-6.5 earthquakes in the dataset, allowing subevents of varying sizes to populate the fault plane and provide a more realistic earthquake source and acceleration ground motion time history modeling. The time domain results are shown to capture the essential characteristics of the ground motions of the three largest earthquakes in the dataset. We present therefore the SBM as a physically consistent source model of SISZ earthquakes for the generation of synthetic strong-motion time histories or peak parameters, with potential applications in scenario simulations and probabilistic or deterministic seismic hazard assessment.

A Macro Seismic Hazard Zonation for Sri Lanka

This paper describes the outcome of a comprehensive study carried out to analyse the seismic hazards affecting Sri Lanka. The main seismic threat is from oceanic earthquakes originating at failed Mannar rift zone and Comorin ridge off the west to south west coast with some secondary influence from South Indian crustal earthquakes. The analyses were performed using Deterministic Seismic Hazard Assessment, Probabilistic Seismic Hazard Assessment and seismic wave propagation using FLAC software ignoring the overburden attenuation within the landmass. The seismic scenario included 100 years earthquake catalogue with an characteristic earthquake of magnitude 6.9 at a distance 90 km from the west coast. Historical records of earthquakes in the vicinity of Sri Lanka indicate that 1615 earthquake was the most significant earthquake that affected Sri Lanka. The analyses show that South West to North West coastal areas are the most vulnerable to seismic hazards. There is also reflection of seismic waves leading to amplification of seismic waves in the central highland. Based on the analyses described above, a seismic hazard map for Sri Lanka dividing the country into two zones of seismic intensity and response spectrum is provided accordingly. The study was constrained by the lack of recorded data of past earthquake responses within the country and a network of seismic stations are proposed in the paper for future data collection.

Seismic Response of Sri Lanka using DSHA Technique

Deterministic seismic hazard assessment developed in 1960s is the oldest method of analysis of seismic ground response. This paper describes the application of seismic hazard assessment to obtain the Peak Ground Acceleration at major cities in Sri Lanka due to an oceanic earthquake. Two earthquakes, occurred in 2011 and 2012 in the above region, were chosen for the validation of suitable attenuation relationships for the region. The comparison shows that, out of the two attenuation relationships investigated, Gitterman et al. (1993) relationship gives the bestprediction.

New 2019 Risk-Targeted Ground Motions for Spectral Design Criteria in Indonesian Seismic Building Code

Indonesia has followed development of new seismic design criteria in the new seismic building codes, from hazard-based in the former SNI-03-1726-2002 to the current risk-based SNI-1726-2012. The major changes in SNI-1726-2012 are using Risk-Targeted Maximum Considered Earthquake (MCER) Spectral Response Acceleration maps. Five years later (2017), the seismic hazard maps have been updated adopting the most recent data and current state of knowledge in probabilistic and deterministic seismic hazard assessment methodologies. To establish the New 2019 Risk Targeted Ground Motion (RTGM) of spectral acceleration (Ss and S1), and risk coefficients (CRS and CR1), for both short (T=0.2s) and 1-second (T=1s) periods, respectively have been developed based on the 2017 Indonesian hazard maps. The RTGM was calculated as the spectral value resulting in 1% probability of building collapse in 50 years through numerical integration of hazard curves and structural capacity. The log-normal standard deviation (?) of the structural capacity envelope has been revised from 0.70 to 0.65. This paper presents the new resulted RTGM maps. Furthermore, the paper also presents revision of seismic amplification factors for 0, 0.2, and 1 second periods (FPGA, Fa, and, Fv) to generate ground surface maximum and design spectra associated with the siteclassifications.

Deterministic seismic hazard assessment of coal fractures in underground coal mine: A case study

Mining seismicity induced by coal fractures can cause strong seismic motions in roadway and result in serious seismic hazards to mining personnel and equipment. In order to assess the seismic hazards induced by coal fractures, a deterministic methodology was proposed based on a coal fracture source model and further developed into a numerical program called Mining-induced Seismic Hazard Assessment software (MSHA). The program accepts user-input material constants of in-situ coal seam and calculates the resultant seismic motions in the roadway; the seismic motions were fully verified by a comparison between the numerical and in situ results. The methodology was further applied to assess the seismic hazards in the panel 92201 of the Sanhejian Coal Mine, the seismic hazards were characterized by the peak particle velocity (PPV) and octahedral shear stress (OSS). The results indicate that the tensile strength of coal constitutes the most significant parameter of the coal fracture source model. Moreover, a general and practical conclusion was obtained that the intensity and scope of seismic hazards in roadway are positively related to the tensile strength of coal, and the left and right sides of the roadway might encounter significant seismic damage under impact of coal fracture. The conclusion is useful for mining engineers to identify the potential seismic hazard in the roadway, and therefore make targeted strategies in mining support system.

DSHA Based Estimation of Peak Ground Acceleration for Madhubani and Supaul Districts Near Bihar–Nepal Region

The districts of Madhubani and Supaul lie near Bihar–Nepal border along foothills of Himalaya. Different attenuation relationships applicable for the Himalayan region have been used to estimate the site-specific Peak Ground Acceleration (PGA) for the Madhubani and Supaul region on the basis of Deterministic Seismic Hazard Assessment (DSHA) study. Seismicity data have been collected from IMD, New Delhi and forty seismotectonic sources were recognized in the region from Seismotectonic Atlas of India (GSI in Seismotectonic atlas of India and its environs, Geological Survey of India, Kolkata, 2000). Hypocentral distances have been measured using ArcGIS software. Maximum Peak ground acceleration value is found to occur for Main Central Thrust fault for both these districts.

A New State‐of‐the‐Art Platform for Probabilistic and Deterministic Seismic Hazard Assessment

ABSTRACTA new computational platform for seismic hazard assessment is presented. The platform, named SeismicHazard, allows characterizing the intensity, uncertainty, and likelihood of ground motions from subduction‐zone (shallow interface and intraslab) and crustal‐zone earthquakes, considering site‐specific as well as regional‐based assessments. The platform is developed as an object‐oriented MATLAB graphical user interface, and it features several state‐of‐the‐art capabilities for probabilistic and deterministic (scenario‐based) seismic hazard assessment. The platform integrates the latest developments in performance‐based earthquake engineering for seismic hazard assessment, including seismic zonation models, ground‐motion models (GMMs), ground‐motion correlation structures, and the estimation of design spectra (uniform hazard spectra, classical conditional mean spectrum (CMS) for a unique tectonic setting). In addition to these standard capabilities, the platform supports advanced features, not commonly found in existing seismic hazard codes, such as (a) computation of source parameters from earthquake catalogs, (b) vector‐probabilistic seismic hazard assessment, (c) hazard evaluation based on conditional GMMs and user‐defined GMMs, (d) uncertainty treatment in the median ground motions through continuous GMM distributions, (e) regional shaking fields, and (f) estimation of CMS considering multiple GMMs and multiple tectonic settings. The results from the platform have been validated against accepted and well‐documented benchmark solutions.

Defining a safe design distance from tectonic structures in urban and regional planning

This study proposed the neotectonics application to urban and regional planning in order to identify high-risk areas by determining fault-related impact zones. This problem requires urgent attention and prompt action because of recent rapid urbanization. As neotectonics can recognize active-seismic faults and associated changes in relief, it can be used to identify areas where natural geological disasters (earthquakes or displacement fractures) are most likely to occur. Seismic activity was studied using neotectonic mapping techniques, empirical equations related to earthquake magnitude and fault length, deterministic seismic hazard assessment based on GIS analysis, and thematic maps showing both areas suitable for human use and exclusion zones in which predicted horizontal acceleration values exceed seismicity thresholds. The main objectives of this study were to minimize the socioeconomic impacts and loss of life associated with seismic activity, to encourage urban development in areas that safeguard life and property, and to improve the safety of existing cities by applying protective measures. Northwestern Greece was selected as an appropriate study area because of the presence of active faults. Large strike-slip faults found in the region could cause significant earthquakes and major disasters, as exemplified by similar fault activations such as the San Andreas Fault in USA.

Seismic sources for southern Pakistan and seismic hazard assessment of Karachi

Karachi is Pakistan’s largest city with population exceeding 18 million and is amongst the top five most congested cities in the world. Karachi has experienced no earthquake related damage in the recorded history of past ~ 175 years. Yet, Karachi is located in a seismically active tectonic setting often compared to Los Angeles with active plate boundary faults and triple junctions within a radius of ~ 150 km. This discrepancy in earthquake history and seismotectonic setting has led to diverse seismic hazard assessments for Karachi ranging from assignment of seismic hazard zones I (least severe) to IV (most severe). Recent assessment adopted in Building Code of Pakistan (2007) assigns an intermediate seismic hazard value of 0.16–0.24 g (Zone IIB) to Karachi, which is broadly accepted but sometimes criticized to be an underestimation (e.g. Bilham et al. Seismol Res Lett 78(6):601–631, 2007). The present study based on a new active faults compilation and seismic sources definition together with incorporation of maximum possible information on historical earthquakes (up to 893AD) has led to a re-assessment of seismic hazard for Karachi using probabilistic and deterministic seismic hazard assessment approaches. According to this study, Karachi is assessed to be prone to ground motions ~ 0.25 g with metropolitan areas having hazard values between 0.21 and 0.25 g for 10% probability of exceedance in 50 years (475-year return period). The deterministic seismic hazard analysis suggest maximum that peak ground acceleration (PGA) varies from 0.19 to 0.99 g in Karachi and its higher values are concentrated around the Nagar Parker fault that is controlling and hazardous for Karachi.

Deterministic seismic hazard assessment for the Makkah region, western Saudi Arabia

Rapid social and industrial development of the Makkah and Jeddah regions emphasizes necessity of reassessment of seismic hazard, results of which are essential for aseismic design, emergency management, and insurance regulations. In this work, the deterministic seismic hazard studies are applied to evaluate level of seismic hazard for the Makkah region using the up-to-date geophysical, geological, and seismological database, and using different techniques. The assessment has been performed in terms of peak ground acceleration (PGA) and presumably active faults are considered as sources of earthquakes. Results of the study show that, in the context of the used models of seismic sources, the level of seismic hazard in the region is controlled by magnitude of earthquakes that may occur at the intersection of NE-SW faults (the Ad Damm fault zone and the Wadi Fatima Shear Zone) and the NNW-oriented faults that run parallel to the Red Sea coast (Red Sea Margin Faults group). It is important to make accurate mapping of faults using up-to-date data and to estimate if the faults are active at present. Particular attention should be given to careful estimation of maximum magnitude of possible earthquakes that can occur along the active fault.

Probabilistic seismic hazard assessment for Bayankhongor aimag of Mongolia

Central Asia is one of the seismically most active regions in the world. Its complex seismicity is due to the collision of the Eurasian and Indian plates, which has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events.The GSHAP project, aiming at hazard assessment on a global scale, indicates that the territory of Bayankhongor aimag, Mongolia, in Central Asia is characterized by maximum bedrock peak ground accelerations for 10% probability of exceedance in 50 years as medium as in range of 80 to 160cm/s2. In this study, which has been carried out within the framework of the project “Seismic microzoning map of center of 12 aimags, Mongolia”, the area source model and different kernel approaches are used for a probabilistic seismic hazard assessment for the Mongolia. The seismic hazard is assessed considering shallow (depth <50 km) seismicity only and employs an updated (with respect to previous projects) earthquake catalogue for the region. The hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the Open Deterministic and Probabilistic Seismic Hazard Assessment (ODPSHA), which is based on the Cornell methodology. The maximum hazard observed in the region reaches 93-98 cm/s2 , which in intensity corresponds to VII in MSK64 scale in the centre of Bayankhongor aimag for 475 years mean return period.

Revisiting seismic hazard assessment for Peninsular Malaysia using deterministic and probabilistic approaches

Abstract. Seismic hazard assessments, both deterministic and probabilistic, for Peninsular Malaysia have been carried out using peak ground acceleration (PGA) data recorded between 2004 and 2016 by the Malaysian Meteorological Department using triaxial accelerometers placed at 19 seismic stations on the peninsula. Seismicity source modelling for the deterministic seismic hazard assessment (DSHA) used historical point sources whereas in the probabilistic (PSHA) approach, line and areal sources were used. The earthquake sources comprised the Sumatran subduction zone (SSZ), Sumatran fault zone (SFZ) and local intraplate (LI) faults. Gutenberg–Richter law b value for the various zones identified within the SSZ ranged between 0.56 and 1.06 (mean=0.82) and for the zones within the SFZ, between 0.57 and 1.03 (mean=0.89). Suitable ground motion prediction equations (GMPEs) for Peninsular Malaysia along with other pertinent information were used for constructing a logic tree for PSHA of the region. The DSHA “critical-worst” scenario suggests PGAs of 0.07–0.80 ms−2 (0.7–8.2 percent g), whilst the PSHA suggests mean PGAs of 0.11–0.55 ms−2 (0.5–5.4 percent g) and 0.20–1.02 ms−2 (1.9–10.1 percent g) at 10 % and 2 % probability of exceedance in 50 years, respectively. DSHA and PSHA, despite using different source models and methodologies, both conclude that the central-western cities of Peninsular Malaysia, located between 2 and 4∘ N, are most susceptible to high PGAs, due to neighbouring active Sumatran sources, SFZ and SSZ. Of the two Sumatran sources, surprisingly, the relatively less active SFZ source with low magnitude seismicity appeared as the major contributor due to its proximity. However, potential hazards due to SSZ mega-earthquakes should not be dismissed. Finally, DSHA performed using the limited LI seismic data from the Bukit Tinggi fault at a reasonable moment magnitude (Mw) value of 5.0 predicted a PGA of ∼0.40 ms−2 at Kuala Lumpur.

Seismic hazard assessment of the Shillong Plateau, India

The Shillong Plateau is an earthquake-prone region in the northeastern India. Based on regional seismotectonic studies, we present here a deterministic seismic hazard assessment (DSHA) and maps of peak horizontal accelerations (PHA) for three largely populated districts – the East Khasi hills, the Ri-Bhoi, and the West Garo hills – within the Shillong Plateau. The hazard analysis methodology is based on the analysis of 72 earthquake sources (active faults) located within 500 km seismotectonic region around the plateau. Using an average sample log-likelihood approach, suitable ground motion prediction equations (GMPEs) are identified. As a variation in hypocentral distances can affect the ranks (or weights) of selected GMPEs, DSHA is performed separately for the three selected districts. Analyses show that the northern part of the East Khasi hills, eastern part of Ri-Bhoi district and the West Garo hills districts exhibit the highest PHA value of 0.46 g at site class A (hard rocks). In addition, response spectra for the Shillong city, Nongpoh, and Tura indicate that the maximum spectral acceleration reaches 0.67 g, 0.77 g, and 0.64 g at 0.1 s, respectively. These assessments indicate that the Barapani, Oldham, and Dauki faults influence significantly the seismic hazard in the studied region.