scholarly journals Preliminary seismic hazard assessment of the Arctic Gakkel ridge and surrounding

2019 ◽  
Vol 1 (1) ◽  
pp. 35-45
Author(s):  
Bela Assinovskaya ◽  
Natal’ia Panas ◽  
Galina Antonovskaya
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Industrial Development ◽  
Seismic Hazard Assessment ◽  
The Arctic ◽  
Primary Data ◽  
Seismogenic Zone ◽  
Earthquake Catalog ◽  
Gakkel Ridge ◽  
Study Region

This study describes primary data, methods of estimation and final results of the preliminary seismic hazard assessment in the region of the Gakkel Ridge that is a northernmost seismogenic zone of the Earth. According to geological data, the region is considered potentially oil and gas, but its industrial development has not yet begun. These authors for the Baltic Sea did the similar work earlier. At the first stage of this study, the earthquake catalog unified in magnitude Mw was compiled for the period from 1912 to 2014. Information on seismic events from historical sources and the ISC catalog was used, as well as the results of observations of the Arkhangelsk seismic network in the Arctic for 2014–2018. The representative part of earthquake data was revealed and the seismic regime has been studied. By seismicity origin, the region is divided into the highly active rift zone of the Gakkel Ridge and the continental slopes of the Barents, Kara and eastern Laptev seas with weaker activity, separated and framed by aseismic areas like the Nansen, Amundsen basins and the Lomonosov Ridge. The seismic zoning of the study region was carried out based on structural analysis of geological and geophysical data. The mapping of probabilistic seismic hazard in terms of maximum accelerations of PGA soil movements for a return period of 500 and 100 years (10% probability of exceedance in the next 50 and 10 years) was conducted using the CRISIS program. As expected, the most dangerous was the Gakkel zone about 200 km wide.

scholarly journals Analysis the 1978–2008 crustal and sub-crustal earthquake catalog of Vrancea region

2012 ◽  
Vol 12 (5) ◽  
pp. 1321-1325 ◽  
Author(s):  
L. Telesca ◽  
V. Alcaz ◽  
I. Sandu
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Earthquake Catalog ◽  
B Values ◽  
Crustal Earthquake ◽  
Quarry Blast ◽  
Vrancea Region ◽  
Completeness Magnitude

Abstract. The crustal and sub-crustal seismicity that occurred in the Vrancea area from 1978 to 2008 is investigated. Due to quarry blast contamination, the analysis of the crustal seismicity was restricted to events that occurred between 20 km and 60 km, considering sub-crustal events as all those that occurred at depths larger than 60 km. The completeness magnitude was estimated between 2.3 and 2.5 for the crustal seismicity and between 2.9 and 3.1 for the sub-crustal one. The Gutenberg-Richter b-values show clear differences between crustal and sub-crustal seismicity, with values around 0.9 and 1.3–1.4, respectively. The analysis performed in this study represents a preliminary issue for the seismic hazard assessment of surrounding regions like Moldova, for which the earthquakes generated in Vrancea represent an important threat.

scholarly journals An updated and unified earthquake catalog from 1787 to 2018 for seismic hazard assessment studies in Mexico

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rashad Sawires ◽  
Miguel A. Santoyo ◽  
José A. Peláez ◽  
Raúl Daniel Corona Fernández
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Large Earthquake ◽  
Seismic Source ◽  
Earthquake Catalog ◽  
Magnitude Conversion ◽  
Seismic Source Models ◽  
Source Models ◽  
Definition Of

Abstract Here we present a new updated and unified Poissonian earthquake catalog for Mexico. The details about the catalog compilation, the removal of duplicate events, unifying the magnitude scales, removal of dependent events through the declustering process and its completeness analysis are presented. Earthquake and focal mechanism data have been compiled from various local, regional and international sources. Large earthquake events (MW ≥ 6.5) have been carefully revised for their epicentral locations and magnitudes from trusted publications. Different magnitude-conversion relationships, compatible with available local and regional ones, has been established to obtain unified moment magnitude estimates for the whole catalog. Completeness periods for the declustered catalog were estimated for the definition of appropriate seismic source models for the whole territory. The final unified Poissonian earthquake catalog spans from 1787 to 2018, covering a spatial extent of 13° to 33°N and 91° to 117°W. This catalog is compatible with other published catalogs providing basis for new analysis related to seismicity, seismotectonics and seismic hazard assessment in Mexico.

Effect of Earthquake Catalog Declustering on Seismic Hazard Assessment

2019 ◽  
Vol 55 (1) ◽  
pp. 59-69
Author(s):  
N. A. Galina ◽  
V. V. Bykova ◽  
R. N. Vakarchuk ◽  
R. E. Tatevosian
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Earthquake Catalog

scholarly journals Neo-deterministic seismic hazard assessment of Corsica-Sardinia block

2021 ◽  
Author(s):  
Enrico Brandmayr ◽  
Franco Vaccari ◽  
Giuliano Francesco Panza
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Earthquake Ground Motion ◽  
Earthquake Catalog ◽  
Hazard Maps ◽  
Source Information ◽  
Deterministic Seismic Hazard ◽  
Seismogenic Nodes

AbstractThe 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 Assessment in Australia: Can Structured Expert Elicitation Achieve Consensus in the “Land of the Fair Go”?

2020 ◽  
Vol 91 (2A) ◽  
pp. 859-873 ◽  
Author(s):  
Jonathan D. Griffin ◽  
Trevor I. Allen ◽  
Matthew C. Gerstenberger
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Epistemic Uncertainty ◽  
Seismic Hazard Assessment ◽  
Building Design ◽  
Expert Elicitation ◽  
Earthquake Catalog ◽  
Logic Tree ◽  
Diverse Range ◽  
Seismic Source Models

Abstract The 2018 National Seismic Hazard Assessment of Australia incorporated 19 alternative seismic-source models developed by members of the Australian seismological community. The diversity of these models demonstrates the deep epistemic uncertainty that exists with regards to how best to characterize seismicity in stable continental regions. In the face of similarly high uncertainty, a diverse range of ground-motion models was proposed for use. A complex logic tree was developed to incorporate the alternative component models into a single hazard model. Expert opinion was drawn upon to weight the alternative logic-tree branches through a structured expert elicitation process. Expert elicitation aims to transparently and reproducibly characterize the community distribution of expert estimates for uncertain quantities and thereby quantify the epistemic uncertainty around estimates of seismic hazard in Australia. We achieve a multimodel rational consensus in which each model, and each expert, is, in accordance with the Australian cultural myth of egalitarianism, given a “fair go”—that is, judged on their merits rather than their status. Yet despite this process, we find that the results are not universally accepted. A key issue is a contested boundary between what is scientifically reducible and what remains epistemologically uncertain, with a particular focus on the earthquake catalog. Furthermore, a reduction, on average, of 72% for the 10% in 50 yr probability of exceedance peak ground acceleration levels compared with those underpinning existing building design standards, challenges the choice of metrics upon which design codes are based. Both quantification of the bounds of epistemic uncertainties through expert elicitation and reduction of epistemic uncertainties through scientific advances have changed our understanding of how the hazard behaves. Dialog between scientists, engineers, and policy makers is required to ensure that as our understanding of the hazard evolves, the hazard metrics used to underpin risk management decisions are re-evaluated to ensure societal aims are achieved.

Probabilistic Seismic Hazard Assessment Using Legacy Data in Georgia

2020 ◽  
Vol 91 (3) ◽  
pp. 1500-1517 ◽  
Author(s):  
Tuna Onur ◽  
Rengin Gok ◽  
Tea Godoladze ◽  
Irakli Gunia ◽  
Giorgi Boichenko ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Data Exchange ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Earthquake Catalog ◽  
The Caucasus ◽  
New Locations ◽  
Legacy Data

Abstract The Caucasus has a documented history of cataloging earthquakes stretching back to the beginning of the Christian era. Instrumental seismic observation in the Caucasus began in 1899, when the first seismograph was installed in Tbilisi, Georgia. During the Soviet era (1921–1991 in Georgia), the number of seismic stations increased in the region, providing better network coverage and a valuable dataset for seismic research. Data from many thousands of earthquakes recorded by this regional network was stored on paper in seismic bulletins. As part of the project outlined in this article, we pulled together and digitized all available paper bulletins from Georgia and neighboring countries. This allowed significant Limprovements in location accuracy and recalculation of more robust moment magnitudes for earthquakes in this region. It also paved the way for future collaboration and data exchange among the countries in the Caucasus. The resulting earthquake catalog with the new locations and magnitudes was used to conduct a probabilistic seismic hazard assessment to support a major update to the building code in Georgia to align it with the European codes. This article outlines the improvements made to the earthquake catalog in Georgia using legacy data and the new hazard assessment based on this improved dataset.

An Earthquake Catalog for Seismic Hazard Assessment in Ecuador

2013 ◽  
Vol 103 (2A) ◽  
pp. 773-786 ◽  
Author(s):  
C. Beauval ◽  
H. Yepes ◽  
P. Palacios ◽  
M. Segovia ◽  
A. Alvarado ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Earthquake Catalog

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

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.

scholarly journals Probabilistic seismic hazard assessment for Hanoi city

2019 ◽  
Vol 41 (4) ◽  
pp. 321-338
Author(s):  
Pham The Truyen ◽  
Nguyen Hong Phuong
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Earthquake Catalog ◽  
Return Periods ◽  
Hazard Maps ◽  
Seismic Hazard Maps ◽  
S Period

In this study, the methodology of probabilistic seismic hazard assessment proposed by Cornell and Esteva in 1968 was applied for Hanoi city, using an earthquake catalog updated until 2018 and a comprehensive seismotectonic model of the territory of Vietnam and adjacent sea areas. Statistical methods were applied for declustering the earthquake catalog, then the maximum likelihood method was used to estimate the parameters of the Gutenberg–Richter Law and the maximum magnitude for each seismic source zone. Two GMPEs proposed by Campbell & Bozorgnia (2008) and Akkar et al., (2014) were selected for use in hazard analysis. Results of PSHA for Hanoi city are presented in the form of probabilistic seismic hazard maps, depicting peak horizontal ground acceleration (PGA) as well as 5-hertz (0.2 sec period) and 1-hertz (1.0 sec. period) spectral accelerations (SA) with 5-percent damping on a uniform firm rock site condition, with 10%, 5%, 2% and 0,5% probability of exceedance in 50 years, corresponding to return times of 475; 975; 2,475 and 9,975 years, respectively. The results of PSHA show that, for the whole territory of Hanoi city, for all four return periods, the predicted PGA values correspond to the intensity of VII to IX degrees according to the MSK-64 scale. As for the SA maps, for all four return periods, the predicted SA values at 1.0 s period correspond to the intensity of VI to VII, while the predicted SA values at 0.2 s period correspond to the intensity of VIII to X according to the MSK-64 scale. This is the last updated version of the probabilistic seismic hazard maps of Hanoi city. The 2019 probabilistic seismic hazard maps of Hanoi city display earthquake ground motions for various probability levels and can be applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy.

The 2018 national seismic hazard assessment of Australia: Quantifying hazard changes and model uncertainties

2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 5-43 ◽  
Author(s):  
Trevor I Allen ◽  
Jonathan D Griffin ◽  
Mark Leonard ◽  
Dan J Clark ◽  
Hadi Ghasemi
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Earthquake Catalog ◽  
Motion Models ◽  
Ground Motion Attenuation ◽  
Attenuation Models ◽  
Instrumental Period ◽  
Ground Motion Models

Seismic hazard assessments in stable continental regions such as Australia face considerable challenges compared with active tectonic regions. Long earthquake recurrence intervals relative to historical records make forecasting the magnitude, rates, and locations of future earthquakes difficult. Similarly, there are few recordings of strong ground motions from moderate-to-large earthquakes to inform development and selection of appropriate ground-motion models (GMMs). Through thorough treatment of these epistemic uncertainties, combined with major improvements to the earthquake catalog, a 2018 National Seismic Hazard Assessment (NSHA18) of Australia has been undertaken. The resulting hazard levels at the 10% in 50-year probability of exceedance level are in general significantly lower than previous assessments, including hazard factors used in the Australian earthquake loading standard ( AS 1170.4–2007 (R2018)), demonstrating our evolving understanding of seismic hazard in Australia. The key reasons for the decrease in seismic hazard factors are adjustments to catalog magnitudes for earthquakes in the early instrumental period, and the use of modern ground-motion attenuation models. This article summarizes the development of the NSHA18 explores uncertainties associated with the hazard model, and identifies the dominant factors driving the resulting changes in hazard compared with previous assessments.

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