scholarly journals Probabilistic Fault Displacement Hazard Analysis for North Tabriz Fault

2021 ◽  
Author(s):  
Mohamadreza Hosseyni ◽  
Habib Rahimi
Keyword(s):  
Return Period ◽  
Hazard Analysis ◽  
Probabilistic Approach ◽  
Surface Displacement ◽  
Return Periods ◽  
Surface Rupture ◽  
Slip Mechanism ◽  
The North ◽  
North Tabriz Fault ◽  
Fault Displacement

Abstract. The probabilistic fault displacement hazard analysis is one of the new methods in estimating the amount of possible displacement in the area at the hazard of causal fault rupture. In this study, using the probabilistic approach and earthquake method introduced by Youngs et al., 2003, the surface displacement of the North Tabriz fault has been investigated, and the possible displacement in different scenarios has been estimated. By considering the strike-slip mechanism of the North Tabriz fault and using the earthquake method, the probability of displacement due to surface ruptures caused by 1721 and 1780 North Tabriz fault earthquakes has been explored. These events were associated with 50 and 60 km of surface rupture, respectively. The 50–60 km long section of the North Tabriz fault was selected as the source of possible surface rupture. We considered two scenarios according to possible displacements, return periods, and magnitudes which are reported in paleoseismic studies of the North Tabriz fault. As the first scenario, possible displacement, return period, and magnitude was selected between zero to 4.5; 645 years and Mw~7.7, respectively. In the second scenario, possible displacement, return period and magnitude were selected between zero to 7.1, 300 years, and Mw~7.3, respectively. For both mentioned scenarios, the probabilistic displacements for the rate of exceedance 5 % in 50, 475, and 2475 years for the principle possible displacements (on fault) of the North Tabriz fault have been estimated. For the first and second scenarios, the maximum probabilistic displacement of the North Tabriz fault at a rate of 5 % in 50 years is estimated to be 186 and 230 cm. Also, mentioned displacements for 5 % exceedance in 475 years and 2475 years in both return periods of 645 and 300 years, are estimated at 469 and 655 cm.

scholarly journals Copula Based Spatial Analysis of Drought Return Period in Southwest of Iran

2020 ◽  
Author(s):  
Mohammadreza Kavianpour ◽  
Mohammadreza Seyedabadi ◽  
Saber Moazami ◽  
Omid Aminoroayaie Yamini
Keyword(s):  
Return Period ◽  
Probabilistic Approach ◽  
Standardized Precipitation Index ◽  
Joint Probability ◽  
Copula Functions ◽  
Khuzestan Province ◽  
Drought Characteristics ◽  
The North ◽  
Significant Difference ◽  
Southwest Of Iran

In the past years, Khuzestan province which is located in the southwest of Iran has experienced severe droughts. Drought can be explained by its characteristics known as duration or severity. However, combination of the two features by probabilistic approach is appeared to be a well improved method to describe the phenomena. The aim of this study is to provide a more accurate statistical method of determining drought based on simultaneous analysis of two drought characteristics. Here, precipitation data from twenty stations were used to determine drought characteristics, by Standardized Precipitation Index (SPI). Joint probability function of two variables were built via copula functions. The drought return period was calculated in the form of two scenarios. The first scenario is, based on an assumption that drought is recognized by at least one of the two specific characteristics. Drought in the second scenario is distinguished by the two characteristics in a joint probabilistic form. According to research results, there was no significant difference between the north and south of Khuzestan in the study of single characteristics of drought. While analyzing two characteristics of the drought, the return period in the north was shorter than the south. The return period of droughts in the east was always shorter than in the west. The drought return period varies from 30 to 52 months and 50 to 87 months for the first and second scenarios, respectively.

Probabilistic Fault Displacement Hazard Assessment (PFDHA) for Nuclear Installations According to IAEA Safety Standards

2021 ◽  
Author(s):  
Alessandro Valentini ◽  
Yoshimitsu Fukushima ◽  
Paolo Contri ◽  
Masato Ono ◽  
Toshiaki Sakai ◽  
...  
Keyword(s):  
Hazard Assessment ◽  
Hazard Analysis ◽  
Surface Displacement ◽  
Hazard Evaluation ◽  
Energy Agency ◽  
Member States ◽  
Site Specific ◽  
Safety Standards ◽  
Fault Displacement ◽  
Technical Guidance

ABSTRACT In the last 10 yr, the International Atomic Energy Agency (IAEA) revised its safety standards for site evaluations of nuclear installations in response to emerging fault displacement hazard evaluation practices developed in Member States. New amendments in the revised safety guidance (DS507) explicitly recommend fault displacement hazard assessment, including separate approaches for candidate new sites versus existing sites. If there is insufficient basis to conclusively determine that a fault is not capable of surface displacement at an existing site, then a probabilistic fault displacement hazard analysis (PFDHA) is recommended to better characterize the hazard. This new recommendation has generated the need for the IAEA to provide its Member States with guidance on performing PFDHA, including its formulation and implementation. This article provides an overview of current PFDHA state-of-practice for nuclear installations that is consistent with the new IAEA safety standards. We also summarize progress in an ongoing international PFDHA benchmark project that will ultimately provide technical guidance to Member States for conducting site-specific fault displacement hazard assessments.

Probability of distributed surface rupturing occurrence and displacement regression for dip-slip earthquakes

2021 ◽  
Author(s):  
Fiia Nurminen ◽  
Francesco Visini ◽  
Stéphane Baize ◽  
Paolo Boncio ◽  
Bruno Pace ◽  
...  
Keyword(s):  
Large Scale ◽  
Hazard Analysis ◽  
Probability Model ◽  
Surface Displacement ◽  
Probability Of Occurrence ◽  
Ranking Scheme ◽  
Surface Ruptures ◽  
Rank 2 ◽  
A Site ◽  
Fault Displacement

<p>Probabilistic fault displacement hazard analysis (PFDHA) estimates the probability of occurrence and the expected exceedance of on-fault (principal fault rupturing; PF) and off-fault (dist ributed rupturing; DR) surface displacement during an earthquake. Here we concent rate on off-fault rupturing on dip-slip earthquakes, and present an original probability model for the occurrence of DR and for the expected exceedance of displacement dist ribution based on an approach named “slicing” (an alternative to the “gridding” approach commonly used). The method is developed based on the compilation and reappraisal of surface ruptures from 32 historical crustal dip-slip earthquakes, with magnitudes ranging from M<sub>w</sub> 4.9 to 7.9. A ranking scheme is applied to distinguish PF (rank 1) from simple DR (rank 2) and t riggered faulting (rank 3). Thus modellers can use prediction equations based on or excluding ruptures st rongly related to local st ructural setting depending on the site of concern. In the case of a st ructural setting at a site where large-scale bending (rank 21, 22) and pre-existing faults (rank 1.5, 3) is considered irrelevant, modelling can be performed considering only the unpredictable DR (rank 2). To minimize bias due to the incomplete nature of the database, we int roduce the “slicing” approach, which considers that the probability of having a surface rupture within slices parallel to the PF is homogeneous along the st rike of each slice. “Slicing” probabilities, computed as a function of magnitude of the earthquake and distance from the PF, are then combined with Monte Carlo simulations that model the dependence of the probability of occurrence of rupture and exceedance of displacement with the dimensions and position of the site of interest with respect to the PF. Finally, both probabilities are combined with existing predictive equations of exceedance of displacement on the PF to calculate fault-displacement hazard curves for sites of interest.</p>

An investigation of methods for Fault Displacement Hazard Assessment for offshore studies

2020 ◽  
Author(s):  
Emilia Fiorini
Keyword(s):  
Hazard Assessment ◽  
Ground Deformation ◽  
Surface Displacement ◽  
Warning System ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Surface Rupture ◽  
Permanent Ground Deformation ◽  
Fault Displacement

<p>The expected surface displacement in the aftermath of an earthquake is an important issue to consider, among others, for pipeline damage. While estimates of permanent ground deformation after an earthquake event is often performed nowadays through the acquisition of Interferometric Synthetic Aperture Radar (InSAR) scenes, this method is only applicable to onshore regions.</p><p>In this work we explore possible methodologies for fault hazard assessment to be applied in offshore regions.</p><p>Methods to estimate the surface rupture hazard for faults of known location and geometry are reviewed, such as the Okada equations available in the Coulomb3 software. However since fault data may be lacking or scarce in offshore areas we also explore the availability of methods to estimate a probabilistic surface rupture assessment, to be applied within the same framework of Probabilistic Seismic Hazard Assessment studies. A simple application of both methods is presented in a hypothetic case study where an early warning system for pipeline damage inspection is required.</p>

PFDHA modelling based on new empirical regressions for distributed faulting on dip-slip earthquakes

2020 ◽  
Author(s):  
Fiia Nurminen ◽  
Stéphane Baize ◽  
Paolo Boncio ◽  
Bruno Pace ◽  
Oona Scotti ◽  
...  
Keyword(s):  
Decision Making ◽  
Active Fault ◽  
Numerical Estimate ◽  
Hazard Analysis ◽  
Normal Faulting ◽  
Surface Rupture ◽  
Regression Parameters ◽  
Surface Ruptures ◽  
A Site ◽  
Fault Displacement

<p>Probabilistic fault displacement hazard analysis (PFDHA) is needed for a numerical estimate of the displacement likely to occur at a site near an active fault in case of a surface faulting earthquake. The methodology is based on parameters describing the probability of occurrence, and the spatial distribution of the displacement on and off-fault. The methodology was created for normal faulting setting, and has been later complemented with the parameters for other slip types, especially regarding the principal fault rupturing. Based on empirical fault displacement data in the Worldwide and Unified Database of Surface Ruptures (SURE), we are presenting new regression parameters for distributed faulting for dip-slip earthquakes. The parameters are used in a computational model for assessing the surface rupture hazard near active dip-slip faults. The modelling results the probability distribution of exceeding a chosen level of displacement, and can be used in stcture design and land-use related decision making in areas where surface faulting hazard should be considered.</p>

scholarly journals Paleoearthquakes and slip rates of the North Tabriz Fault, NW Iran: preliminary results

2009 ◽  
Vol 46 (5) ◽  
Author(s):  
K. Hessami ◽  
D. Pantosti ◽  
H. Tabassi ◽  
E. Shabanian ◽  
M. R. Abbassi ◽  
...  
Keyword(s):  
Slip Rates ◽  
Nw Iran ◽  
Preliminary Results ◽  
The North ◽  
North Tabriz Fault

scholarly journals Joint return periods in hydrology: a critical and practical review focusing on synthetic design hydrograph estimation

2012 ◽  
Vol 9 (5) ◽  
pp. 6781-6828 ◽  
Author(s):  
S. Vandenberghe ◽  
M. J. van den Berg ◽  
B. Gräler ◽  
A. Petroselli ◽  
S. Grimaldi ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Return Period ◽  
Three Dimensional ◽  
Distribution Functions ◽  
Return Periods ◽  
Design Variables ◽  
Joint Return ◽  
Design Values ◽  
Multivariate Frequency Analysis ◽  
Joint Return Period

Abstract. Most of the hydrological and hydraulic studies refer to the notion of a return period to quantify design variables. When dealing with multiple design variables, the well-known univariate statistical analysis is no longer satisfactory and several issues challenge the practitioner. How should one incorporate the dependence between variables? How should the joint return period be defined and applied? In this study, an overview of the state-of-the-art for defining joint return periods is given. The construction of multivariate distribution functions is done through the use of copulas, given their practicality in multivariate frequency analysis and their ability to model numerous types of dependence structures in a flexible way. A case study focusing on the selection of design hydrograph characteristics is presented and the design values of a three-dimensional phenomenon composed of peak discharge, volume and duration are derived. Joint return period methods based on regression analysis, bivariate conditional distributions, bivariate joint distributions, and Kendal distribution functions are investigated and compared highlighting theoretical and practical issues of multivariate frequency analysis. Also an ensemble-based method is introduced. For a given design return period, the method chosen clearly affects the calculated design event. Eventually, light is shed on the practical implications of a chosen method.

Sign in / Sign up

Export Citation Format

Share Document