Probabilistic seismic hazard map for Bulgaria as a basis for a new building code

Abstract. A seismic hazard map proposed as part of a new building code for Bulgaria is presented here on basis of the recommendations in EUROCODE 8. Seismic source zones within an area of about 200 km around Bulgaria were constructed considering seismicity, neotectonic and geological development. The most time consuming work was to establish a homogeneous earthquake catalogue out of different catalogues. The probabilistic seismic hazard assessment in terms of intensities is performed following Cornell (1968) with the program EQRISK (see McGuire, 1976), modified by us for use of intensities. To cope with the irregular isoseismals of the Vrancea intermediate depth earthquakes a special attenuation factor is introduced (Ardeleanu et al., 2005), using detailed macroseismic maps of three major earthquakes. The final seismic hazard is the combination of both contributions, of zones with crustal earthquakes and of the Vrancea intermediate depth earthquakes zone. Calculations are done for recurrence periods of 95, 475 and 10 000 years.

Download Full-text

Probabilistic seismic hazard map for Romania as a basis for a new building code

Natural Hazards and Earth System Science ◽

10.5194/nhess-5-679-2005 ◽

2005 ◽

Vol 5 (5) ◽

pp. 679-684 ◽

Cited By ~ 26

Author(s):

L. Ardeleanu ◽

G. Leydecker ◽

K.-P. Bonjer ◽

H. Busche ◽

D. Kaiser ◽

...

Keyword(s):

Seismic Hazard ◽

Grid Point ◽

Building Code ◽

Probabilistic Seismic Hazard Assessment ◽

Eurocode 8 ◽

Probabilistic Seismic Hazard ◽

Hazard Map ◽

Intermediate Depth ◽

Attenuation Law ◽

Seismic Hazard Map

Abstract. A seismic hazard map proposed as part of a new building code for Romania is presented here on basis of the recommendations in EUROCODE 8. Seismic source zones within an area of about 200 km around Romania were constructed considering seismicity, neotectonics and geological development. The probabilistic seismic hazard assessment in terms of intensities is performed following Cornell (1968) with the program EQRISK (see Mc Guire, 1976), modified by us for use of intensities. To cope with the irregular isoseismals of the Vrancea intermediate depth earthquakes a factor Ω is introduced to the attenuation law (Kövesligethy, 1907). Using detailed macroseismic maps of three earthquakes Ω is calculated by fitting the attenuation law to observed intensities, i.e. to local ground conditions. Strong local variation of Ω is avoided by a gridding of 0.5° in longitude and 0.25° in latitude. The contribution of the Vrancea intermediate depth zone to the seismic hazard at each grid point is computed with the corresponding representative Ω. A seismogenic depth of 120 km is assumed. The final seismic hazard is the combination of both contributions, of zones with crustal earthquakes and of the Vrancea intermediate depth earthquakes zone. Calculations are done for a recurrence period of 95, 475 and 10000 years. All maps show the dominating effects of the intermediate depth earthquakes in the Vrancea zone, also for the capital Bucharest.

Download Full-text

Seismotectonic model and probabilistic seismic hazard assessment for Papua New Guinea

Bulletin of Earthquake Engineering ◽

10.1007/s10518-020-00966-1 ◽

2020 ◽

Vol 18 (15) ◽

pp. 6571-6605 ◽

Cited By ~ 1

Author(s):

Hadi Ghasemi ◽

Phil Cummins ◽

Graeme Weatherill ◽

Chris McKee ◽

Martyn Hazelwood ◽

...

Keyword(s):

Seismic Hazard ◽

Papua New Guinea ◽

Hazard Assessment ◽

Seismic Hazard Assessment ◽

Seismic Source ◽

New Guinea ◽

Building Code ◽

Tectonic Activity ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard

Abstract Papua New Guinea (PNG) lies in a belt of intense tectonic activity that experiences high levels of seismicity. Although this seismicity poses significant risks to society, the Building Code of PNG and its underpinning seismic loading requirements have not been revised since 1982. This study aims to partially address this gap by updating the seismic zoning map on which the earthquake loading component of the building code is based. We performed a new probabilistic seismic hazard assessment for PNG using the OpenQuake software developed by the Global Earthquake Model Foundation (Pagani et al. in Seism Res Lett 85(3):692–702, 2014). Among other enhancements, for the first time together with background sources, individual fault sources are implemented to represent active major and microplate boundaries in the region to better constrain the earthquake-rate and seismic-source models. The seismic-source model also models intraslab, Wadati–Benioff zone seismicity in a more realistic way using a continuous slab volume to constrain the finite ruptures of such events. The results suggest a high level of hazard in the coastal areas of the Huon Peninsula and the New Britain–Bougainville region, and a relatively low level of hazard in the southwestern part of mainland PNG. In comparison with the seismic zonation map in the current design standard, it can be noted that the spatial distribution of seismic hazard used for building design does not match the bedrock hazard distribution of this study. In particular, the high seismic hazard of the Huon Peninsula in the revised assessment is not captured in the current building code of PNG.

Download Full-text

Probabilistic Seismic Hazard Assessment for United Arab Emirates, Qatar and Bahrain

Applied Sciences ◽

10.3390/app10217901 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7901

Author(s):

Rashad Sawires ◽

José A. Peláez ◽

Mohamed Hamdache

Keyword(s):

Seismic Hazard ◽

United Arab Emirates ◽

Hazard Assessment ◽

Return Period ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard ◽

Earthquake Catalog ◽

Intermediate Depth ◽

Seismic Source Models

A probabilistic seismic hazard assessment in terms of peak ground acceleration (PGA) and spectral acceleration (SA) values, for both 10% and 5% probability of exceedance in 50 years, has been performed for the United Arab Emirates, Qatar, and Bahrain. To do that, an updated, unified, and Poissonian earthquake catalog (since 685 to 2019) was prepared for this work. Three alternative seismic source models were considered in a designed logic-tree framework. The discrimination between the shallow and intermediate depth seismicity along the Zagros and the Makran regions was also considered in this assessment. Three alternative ground-motion attenuation models for crustal earthquakes and one additional for intermediate-depth ones have been selected and applied in this study, considering the predominant stress regime computed previously for each defined source. This assessment highlights that the maximum obtained hazard values are observed in the northeastern part of the studied region, specifically at Ras Al-Khaimah, Umm Al-Quwain, and Fujaira, being characterized by mean PGA and SA (0.2 s) pair values equal to (0.13 g, 0.30 g), (0.12 g, 0.29 g), and (0.13 g, 0.28 g), respectively, for a 475-year return period and for B/C National Earthquake Hazards Reduction Program (NEHRP) boundary site conditions. Seismic hazard deaggregation in terms of magnitude and distance was also computed for a return period of 475 years, for ten emirates and cities, and for four different spectral periods.

Download Full-text

Seismic hazard map of Austria

10.5194/egusphere-egu2020-4820 ◽

2020 ◽

Author(s):

Stefan Weginger ◽

Papí Isaba María del Puy ◽

Yan Jia ◽

Wolfgang Lenhardt

Keyword(s):

Seismic Hazard ◽

Seismic Hazard Assessment ◽

Least Square ◽

Probabilistic Seismic Hazard Assessment ◽

Hazard Map ◽

Uniform Hazard Spectra ◽

Statistical Parameters ◽

Smoothed Seismicity ◽

Local Measurements ◽

Seismic Hazard Map

<p>After 25 years, a new seismic hazard map for Austria was created. The improvements in the Probabilistic Seismic Hazard Assessment (PSHA) are based on expanded and updated catalog data with improved depth, source-mechanism and moment magnitudes. Locally adapted ground motion prediction equations (GMPE) were calculated by applying a least square adjustment to the local measurements. A neuronal networks approach was successfully tested. The final selection is carried out by using statistical parameters, like Log-Likelihood and Euclidean Distance Range. Verified calculation methods, like Bayesian Penalized Maximum Likelihood and modified Gutenberg Richter, were used. The uncertainties have been considered by using the covariance matrix according to Stromeyer (2015). The PSHA approach combines a model of seismic zones (area sources), which is composed of zones and superzones, a zone-free model (smoothed seismicity) and a model with geological fault zones. A logic tree function was used to merge the models, the maximum magnitudes (by EPRI-Approach) and the GMPE. The calculations were carried out with the Openquake software framework. The results were compared with the current norm and the results of neighboring countries. Furthermore, the uniform hazard spectra were compared with the new Eurocode draft.</p>

Download Full-text