Seismogenic nodes as a viable alternative to seismogenic zones and observed seismicity for the definition of seismic hazard at regional scale

A fixed increment of magnitude is equivalent to multiply the seismic moment by a factor γEM related to the partial factor γq acting on the seismic moment representing the fault. A comparison is made between the hazard maps obtained with the Neo-Deterministic Seismic Hazard Assessment (NDSHA), using two different approaches: one based on the events magnitude, listed in parametric earthquake catalogues compiled for the study areas, with sources located within the seismogenic zones; the other uses the seismogenic nodes identified by means of pattern recognition techniques applied to morphostructural zonation (MSZ), and increases the reference magnitude by a constant amount tuned by the safety factor γEM.Using γEM=2.0, in most of the territory the two approaches produce totally independent, comparable hazard maps, based on the quite long Italian catalogue. This represents a validation of the seismogenic nodes method and a tuning of the safety factor γEM at about 2.

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Neo-deterministic seismic hazard assessment of Corsica-Sardinia block

RENDICONTI LINCEI ◽

10.1007/s12210-021-01033-w ◽

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.

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Seismic hazard maps of Italy

Annals of Geophysics ◽

10.4401/ag-4327 ◽

1998 ◽

Vol 41 (2) ◽

Author(s):

D. Slejko ◽

L. Peruzza ◽

A. Rebez

Keyword(s):

Seismic Hazard ◽

Probabilistic Approach ◽

Seismic Hazard Assessment ◽

Data File ◽

Macroseismic Intensity ◽

Hazard Maps ◽

Seismic Zonation ◽

Seismicity Parameters ◽

Global View ◽

Definition Of

The Italian "Gruppo Nazionale per la Difesa dai Terremoti" has conducted a project in recent years for assessing seismic hazard in the national territory to be used as a basis for the revision of the current seismic zonation. In this project the data on the major earthquakes were reassessed and a new earthquake data file prepared. Definition of a seismotectonic model for the whole territory, based on a structural-kinematic analysis of Italy and the surrounding regions, led to the definition of 80 seismogenic zones, for which the geological and seismic characteristics were determined. Horizontal PGA and macroseismic intensity were used as seismicity parameters in the application of the Cornell probabilistic approach. The main aspects of the seismic hazard assessment are here described and the results obtained are presented and discussed. The maps prepared show the various aspects of seismic hazard which need to be considered for a global view of the problem. In particular, those with a 475-year return period, in agreement with the specifications of the new seismic Eurocode EC8, can be considered basic products for a revision of the present national seismic zonation.

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Geostatistical approach for multi-scale seismic liquefaction risk assessment

10.5194/egusphere-egu21-12789 ◽

2021 ◽

Author(s):

Rose Line Spacagna ◽

Massimo Cesarano ◽

Stefania Fabozzi ◽

Edoardo Peronace ◽

Attilio Porchia ◽

...

Keyword(s):

Regional Scale ◽

Morphological Characteristics ◽

Predisposing Factors ◽

Data Availability ◽

Hazard Maps ◽

Multi Scale ◽

Seismic Liquefaction ◽

Research Activities ◽

Geostatistical Approach ◽

Definition Of

<p>The Seismic Microzonation studies (SMs), promoted all over the Italian territory by the Department of Civil Protection, provide fundamental knowledge of the subsoil response in seismic conditions at the urban scale. Amplification phenomena related to lithostratigraphic and morphological characteristics, instabilities and permanent deformations activated by the earthquake, are highlighted in hazard maps produced at increasing reliability levels (level 1 to 3 of SM). In particular, zones prone to liquefaction instability are firstly identified following the predisposing factors, such as geological and geotechnical characteristics and seismicity. The robustness of the definition of these areas is strongly correlated to the availability and the spatial distribution of surveys. Moreover, the typology and quality of the investigations considerably influence the method of analysis and the degree of uncertainty of the results.</p><p>This work aims to establish an updated procedure of the actual SM guidelines and integrates recent research activities at different levels of SMs, to improve the hazard maps accuracy in terms of liquefaction susceptibility. For the scope, the case of the Calabria region in the south of Italy, well known for the high level of seismicity, was studied. At a regional scale, the base-level analysis was implemented for a preliminary assessment of the Attention Zones (AZ), potentially susceptible to liquefaction. The predisposing factors were implemented at a large scale, taking advantage of geostatistical tools to quantify uncertainties and filter inconsistent data. The regional-scale analysis allowed to highlight areas prone to liquefaction and effectively addressed the subsequent level of analysis. At a local scale, the quantitative evaluation of the liquefaction potential was assessed using simplified methods, integrating data from different survey types (CPT, SPT, Down-Hole, Cross-Hole, MASW) available in SM database. The definition of Susceptibility Zones (SZ) was provided considering additional indexes, combining the results obtained from different surveys typologies and quantifying the uncertainty due to the limited data availability with geostatistical methods. The analyses at the regional and municipality scale were matched with seismic liquefaction evidence, well documented in past seismic events. This multi-scale process optimises resource allocation to reduce the level of uncertainty for subsequent levels of analysis, providing useful information for land management and emergency planning.</p>

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

Scientific Data ◽

10.1038/s41597-019-0234-z ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 3

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.

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Seismic hazard maps of Peshawar district for various return periods

10.5194/nhess-2019-299 ◽

2019 ◽

Author(s):

Khalid Mahmood ◽

Usman Khan ◽

Qaiser Iqbal ◽

Naveed Ahmad

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Target Location ◽

Epistemic Uncertainty ◽

Source Parameters ◽

Seismic Source ◽

Return Periods ◽

Hazard Maps ◽

Earthquake Catalogues ◽

Seismic Hazard Maps

Abstract. The probabilistic seismic hazard analysis of Peshawar District has been conducted in for a grid size of 0.01. The seismic sources for the target location are defined as the area polygon with uniform seismicity for which, the earthquake catalogues were obtained from different worldwide seismological network data. The earthquake catalogues obtained in different magnitude scale was converted into moment magnitude using regression analysis. The homogenized catalogue was then further subdivided into shallow crustal and deep subduction zone earthquake events for which, the seismic source parameters were obtained using Bounded Gutenberg-Richter Recurrence law. The seismic hazard maps were prepared in term of PGA at bedrock using the different ground motion attenuation relationships. The study shows that; the selection of appropriate ground motion prediction equation is an important factor in deciding the seismic hazard of Peshawar District. The inclusion of deep subduction earthquake does not add significantly to the seismic hazard. The calculated seismic hazard map for shallow crustal earthquake after including the epistemic uncertainty was in close agreement to that developed by BCP-2007 for a return period of 475 years on bedrock. The seismic hazard maps for other return periods i.e., 50, 100, 250, 475 and 2500 years were then prepared.

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SEISMIC HAZARD ESTIMATION IN STABLE CONTINENTAL REGIONS: DOES PSHA MEET THE NEEDS FOR MODERN ENGINEERING DESIGN IN AUSTRALIA?

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.53.1.22-36 ◽

2020 ◽

Vol 53 (1) ◽

pp. 22-36 ◽

Cited By ~ 3

Author(s):

Trevor I. Allen

Keyword(s):

Seismic Hazard ◽

Hazard Analysis ◽

Ground Motions ◽

Seismic Hazard Assessment ◽

Earthquake Hazard ◽

Exceedance Probability ◽

Earthquake Catalogues ◽

Seismic Safety ◽

Seismic Demands ◽

Almost All

Damaging earthquakes in Australia and other regions characterised by low seismicity are considered low probability but high consequence events. Uncertainties in modelling earthquake occurrence rates and ground motions for damaging earthquakes in these regions pose unique challenges to forecasting seismic hazard, including the use of this information as a reliable benchmark to improve seismic safety within our communities. Key challenges for assessing seismic hazards in these regions are explored, including: the completeness and continuity of earthquake catalogues; the identification and characterisation of neotectonic faults; the difficulties in characterising earthquake ground motions; the uncertainties in earthquake source modelling, and; the use of modern earthquake hazard information to support the development of future building provisions. Geoscience Australia recently released its 2018 National Seismic Hazard Assessment (NSHA18). Results from the NSHA18 indicate significantly lower seismic hazard across almost all Australian localities at the 1/500 annual exceedance probability level relative to the factors adopted for the current Australian Standard AS1170.4–2007 (R2018). These new hazard estimates have challenged notions of seismic hazard in Australia in terms of the recurrence of damaging ground motions. This raises the question of whether current practices in probabilistic seismic hazard analysis (PSHA) deliver the outcomes required to protect communities and infrastructure assets in low-seismicity regions, such as Australia. This manuscript explores a range of measures that could be undertaken to update and modernise the Australian earthquake loading standard, in the context of these modern seismic hazard estimates, including the use of alternate ground-motion exceedance probabilities for assigning seismic demands for ordinary-use structures. The estimation of seismic hazard at any location is an uncertain science, particularly in low-seismicity regions. However, as our knowledge of the physical characteristics of earthquakes improve, our estimates of the hazard will converge more closely to the actual – but unknowable – (time independent) hazard. Understanding the uncertainties in the estimation of seismic hazard is also of key importance, and new software and approaches allow hazard modellers to better understand and quantify this uncertainty. It is therefore prudent to regularly update the estimates of the seismic demands in our building codes using the best available evidence-based methods and models.

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Neo-deterministic seismic hazard maps of Kosovo

Vietnam Journal of Earth Sciences ◽

10.15625/2615-9783/16328 ◽

2021 ◽

Author(s):

Enrico Brandmayr ◽

Vaccari Franco ◽

Romanelli Fabio ◽

Vlahovic Gordana ◽

Panza Giuliano Francesco

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Seismic Hazard Assessment ◽

Active Regions ◽

Earthquake Hazard ◽

Earthquake Ground Motion ◽

Hazard Maps ◽

Source Information ◽

Deterministic Seismic Hazard ◽

Traditional Construction

Kosovo is one of the most seismically active regions in Europe, lying within the Alpine-Mediterranean tectonic belt. Historical records for the region show several catastrophic earthquakes with epicentral intensity IX (MCS). However, due to Kosovo’s high population density, high prevalence of traditional construction, and insufficient enforcement of building codes, Kosovo is vulnerable to earthquake damage. In this study, we present earthquake hazard maps for bedrock conditions in Kosovo based on the well-known Neo-deterministic Seismic Hazard Assessment (NDSHA) method. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures to generate realistic time series, used as input for the computation of several ground motion parameters, integrating the available knowledge of seismic history, seismogenic zones and morphostructural nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved, producing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. Our maps are generally consistent with the observed intensity IX (MCS) and suggest that, in some instances, intensity X could be reached.

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

E3S Web of Conferences ◽

10.1051/e3sconf/202015603010 ◽

2020 ◽

Vol 156 ◽

pp. 03010

Author(s):

I Wayan Sengara ◽

Masyhur Irsyam ◽

Indra Djati Sidi ◽

Andri Mulia ◽

Muhamad Asrurifak ◽

...

Keyword(s):

Seismic Hazard ◽

Spectral Response ◽

Ground Surface ◽

Seismic Hazard Assessment ◽

Design Criteria ◽

Hazard Maps ◽

Building Collapse ◽

Structural Capacity ◽

Seismic Amplification ◽

Log Normal

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.

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Nationwide 7.5-Arc-Second Japan Engineering Geomorphologic Classification Map and Vs30 Zoning

Journal of Disaster Research ◽

10.20965/jdr.2013.p0904 ◽

2013 ◽

Vol 8 (5) ◽

pp. 904-911 ◽

Cited By ~ 20

Author(s):

Kazue Wakamatsu ◽

◽

Masashi Matsuoka ◽

Keyword(s):

Seismic Hazard ◽

Local Governments ◽

Seismic Hazard Assessment ◽

Shear Velocity ◽

Hazard Maps ◽

Seismic Risk Analysis ◽

Average Shear ◽

Ground Conditions ◽

Estimation System ◽

Ground Condition

Local geological and ground conditions play important roles in characterizing and estimating hazards in seismic hazard assessment. The authors recently constructed the Japan Engineering Geomorphologic Classification Map (JEGM), which is a systematically standardized GIS-based ground-condition map containing attributes of geomorphologic classification in grid cells of 7.5 arc-seconds in latitude × 11.25 arc-seconds in longitude for Japan nationwide. This paper introduces the concept of developing the 7.5-arc-second JEGM, and presents sample JEGM images. As an example of the database’s application in estimating hazards, the average shear velocity of the ground in the upper 30m, Vs30 is estimated and mapped for Japan nationwide. Other applications being released include seismic hazard maps of Japan, seismic risk analysis by Central Disaster Prevention Council and local governments, and a Quick Estimation System for Earthquake Maps Triggered by Observation Records (QuiQuake).

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Seismic hazard analysis: a comparative study

Canadian Journal of Civil Engineering ◽

10.1139/l06-062 ◽

2006 ◽

Vol 33 (9) ◽

pp. 1156-1171 ◽

Cited By ~ 21

Author(s):

H P Hong ◽

K Goda ◽

A G Davenport

Keyword(s):

Seismic Hazard ◽

Seismic Hazard Assessment ◽

Historical Seismicity ◽

Hazard Maps ◽

Uniform Hazard Spectra ◽

Attenuation Relations ◽

Seismic Hazard Maps ◽

Cell Method ◽

Thiessen Polygon ◽

The Impact

The quantitative seismic hazard maps for the 1970s National Building Code of Canada were evaluated using the Davenport–Milne method. The Cornell–McGuire method is employed to develop recent seismic hazard maps of Canada. These methods incorporate the information on seismicity, magnitude-recurrence relations, and ground motion (or response) attenuation relations. The former preserves and depends completely on details of the historical seismicity; the latter smoothes the irregular spatial occurrence pattern of the historical seismicity into seismic source zones. Further, the Epicentral Cell method, which attempts to incorporate the preserving and smoothing aspect of these methods, has been developed. However, the impact of the adopted assumptions on the estimated quantitative seismic hazard has not been investigated. This study provides a comparative seismic hazard assessment using the above-mentioned methods and simulation-based algorithms. The analysis results show that overall the Davenport–Milne method gives quasi-circular seismic hazard contours near significant historical events, and the Cornell–McGuire method smoothes the transition of contours. The Epicentral Cell method provides estimates approximately within the former and the latter. Key words: epicentral cell method, probability, seismic hazard, Thiessen polygon, Voronoi, uniform hazard spectra.

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