We introduce a new approach for ground motion relations (GMR) in the probabilistic seismic hazard analysis (PSHA), being influenced by the extreme value theory of mathematical statistics. Therein, we understand a GMR as a random function. We derive mathematically the principle of area-equivalence; wherein two alternative GMRs have an equivalent influence on the hazard if these GMRs have equivalent area functions. This includes local biases. An interpretation of the difference between these GMRs (an actual and a modeled one) as a random component leads to a general overestimation of residual variance and hazard. Beside this, we discuss important aspects of classical approaches and discover discrepancies with the state of the art of stochastics and statistics (model selection and significance, test of distribution assumptions, extreme value statistics). We criticize especially the assumption of logarithmic normally distributed residuals of maxima like the peak ground acceleration (PGA). The natural distribution of its individual random component (equivalent to exp(epsilon_0) of Joyner and Boore 1993) is the generalized extreme value. We show by numerical researches that the actual distribution can be hidden and a wrong distribution assumption can influence the PSHA negatively as the negligence of area equivalence does. Finally, we suggest an estimation concept for GMRs of PSHA with a regression-free variance estimation of the individual random component. We demonstrate the advantages of event-specific GMRs by analyzing data sets from the PEER strong motion database and estimate event-specific GMRs. Therein, the majority of the best models base on an anisotropic point source approach. The residual variance of logarithmized PGA is significantly smaller than in previous models. We validate the estimations for the event with the largest sample by empirical area functions. etc.
Objective testing is a key issue in the process of revision and improvement of seismic hazard assessments. Therefore we continue the rigorous comparative analysis of past and newly available hazard maps for the territory of Italy against the seismic activity observed in reality. The final Global Seismic Hazard Assessment Program (GSHAP) results and the most recent version of Seismic Hazard Harmonization in Europe (SHARE) project maps, along with the reference hazard maps for the Italian seismic code, all obtained by probabilistic seismic hazard assessment (PSHA), are cross-compared to the thre…
International Seismic Safety Organization (ISSO) has been formed to promote public safety by being prepared for the largest potential events which can happen at any time, rather than for certain probable events which have been exceeded in several recent earthquakes with disastrous consequences. The position of ISSO is available now in English, Italian, Russian, Hebrew, Spanish, and Hindi at http://www.issoquake.org. That position has been misrepresented elsewhere and this short note is to counter such inaccurate viewpoints.
This paper evaluates the vulnerability of highway bridges in areas subjected to human induced seismic hazards that are commonly associated with petroleum activities and wastewater disposal. Recently, there has been a significant growth in the rate of such earthquakes, especially in areas of Texas, Oklahoma, and Kansas. The magnitudes of these earthquakes are usually lower than tectonic earthquakes that can occur in high seismic regions; however, such induced earthquakes can occur in areas that historically have had negligible seismicity. Thus, the infrastructure in these locations was likely d…
Physics-Based Seismic Hazard and Risk Assessment: A New Paradigm for Earthquake Forecasting
Institute of Risk Analysis, Prediction and Management (Risks-X), Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology (SUSTech)（南方科技大学高等交叉研究院风险、预测与管理研究所）；Istituto Nazionale di Geofisica e Vulcanologia (INGV)（意大利国家地球物理学与火山学研究所）
Waveform-Based Probabilistic Seismic Hazard Analysis Using Ground-Motion Generative Models
National Research Institute for Resilience Engineering Research Center Earth Science and Disaster Resilience Graduate School of Engineering（国立研究开发法人防灾科学技术研究所地球科学与灾害韧性研究生院）；The University of Tokyo（东京大学）
The State of Tripura lies in northeast India which is considered to be one of the most seismically active regions of the world. In the present study, a realistic Probabilistic Seismic Hazard Assessment (PSHA) of Tripura State based on improved seismogenic sources considering layered polygonal sources corresponding to hypo-central depth range of 0 to 25 km, 25 to 70 km and 70 to 180 km, respectively and data driven selection of suitable Ground Motion Prediction Equations (GMPEs) in a logic tree framework is presented. Analyses have been carried out by formulating a layered seismogenic source zo…
It is shown that considering a fixed increment of a given magnitude at a fault is equivalent to factoring the mechanical moment at the fault as done in structural engineering with the applied loads, by the most currently used structural engineering standards (e.g. Eurocodes). A special safety factor is introduced and related to the partial factor acting on the mechanical moment representing the fault. A comparison is then made between the hazard maps obtained for Italy with the Neo Deterministic Seismic Hazard Assessment (NDSHA) technique, using two approaches for the definition of the seismic…
The reliable statistical characterization of the spatial and temporal properties of large earthquakes occurrence is one of the most debated issues in seismic hazard assessment, due to the unavoidably limited observations from past events. We show that pattern recognition techniques, which are designed in a formal and testable way, may provide significant space-time constraints about impending strong earthquakes. This information, when combined with physically sound methods for ground shaking computation, like the neo-deterministic approach (NDSHA), may produce effectively preventive seismic ha…
Cross-Sectional and Spatio-Temporal Analysis of Seismicity Parameters in the Zagros Orogenic Belt: Insights into Crustal Stress Distribution and Seismic Hazard
Farhangian University（法尔坎吉安大学）；Ankara University（安卡拉大学）；Arak University（阿拉克大学）；the University of Tokyo（东京大学）；Skolkovo Institute of Science and Technology (Skoltech)（斯科尔科沃科学技术研究所）
The Neo-Deterministic Seismic Hazard Assessment (NDSHA) method reliably and realistically simulates the suite of earthquake ground motions that may impact civil populations as well as their heritage buildings. The modeling technique is developed from comprehensive physical knowledge of the seismic source process, the propagation of earthquake waves and their combined interactions with site effects. NDSHA effectively accounts for the tensor nature of earthquake ground motions formally described as the tensor product of the earthquake source functions and the Green Functions of the pathway. NDSH…
Mitigation and optimization of induced seismicity using physics-based forecasting
Scripps Institution of Oceanography, University of California San Diego（斯克里普斯海洋学研究所，加州大学圣迭戈分校）；Department of Geological Sciences, San Diego State University（地质科学系，圣地亚哥州立大学）；Institute of Geological Sciences, of Freie Universität Berlin（柏林自由大学地质科学研究所）
A scenario-based Neo-Deterministic approach to Seismic Hazard Assessment (NDSHA) is available nowadays, which permits considering a wide range of possible seismic sources as the starting point for deriving scenarios by means of full waveforms modeling. The method does not make use of attenuation relations and naturally supplies realistic time series of ground shaking, including reliable estimates of ground displacement, readily applicable to complete engineering analysis. Based on the neo-deterministic approach, an operational integrated procedure for seismic hazard assessment has been develop…
The discovery of gas in Groningen in 1959 has been a massive boon to the Dutch economy. From the 1990s onwards though, gas production has led to induced seismicity. In this paper, we carry out a comprehensive exploratory analysis of the spatio-temporal earthquake catalogue. We develop a non-parametric adaptive kernel smoothing technique to estimate the spatio-temporal hazard map and to interpolate monthly well-based gas production statistics. Second- and higher-order inhomogeneous summary statistics are used to show that the state of the art rate-and-state models for the prediction of seismic …
The presence of topography influences the seismic ground motion and may result in strong amplifications, generally at the top of hills and reliefs. The increasing urbanization of hills requires an accurate estimation of these effects even in areas of moderate seismicity. The simplified coefficients provided by the Eurocodes8 do not depend on the frequency and underestimate the amplification in many situations, which justifies the development of new methods based on easily accessible data. The city of Menton, located in the southeast of France, between the Alps and the Ligurian basin, is one of…
An Agentic Interface for End-to-End Probabilistic Seismic Hazard and Risk Analysis
Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS — Laboratoire de Mécanique Paris-Saclay（巴黎-萨克莱大学、中央超导学院、巴黎-萨克莱高等师范学院、国家科学研究中心、LMPS——巴黎-萨克莱力学实验室）；GFZ Helmholtz Centre for Geosciences（德国地球科学霍普夫兹中心）；University of Potsdam, Institute of Geosciences（波茨坦大学、地球科学学院）
Attenuation study of a province is considered as a basic quantity for seismic hazard assessment, ground motion simulation process and source parameter studies. It is already established that the study of two physical processes, first, the seismic sources and second, propagation of the waves, is essential for seismic-hazard mapping, attenuation being one of the properties paying importance to the latter. Here, a computational tool entitled CodaQback is presented. Based on back scattering model, this versatile software is equipped with user friendly graphical user interface. It also allows quick…
Dynamic parameters of structures extracted from ambient vibration measurements: an aid for the seismic vulnerability assessment of existing buildings in moderate seismic hazard regions
A narrow rectilinear valley in the French Pyrenees, affected in the past by damaging earthquakes, has been chosen as a test site for soil response characterization. The main purpose of this initiative was to compare experimental and numerical approaches. A temporary network of 10 stations has been deployed along and across the valley during two years; parallel various experiments have been conducted, in particular ambient noise recording, and seismic profiles with active sources for structure determination at the 10 sites. Classical observables have been measured for site amplification evaluat…
For historical buildings and monuments, i.e. when considering time intervals of about a million year (we do not want to loose cultural heritage), the applicability of standard estimates of seismic hazard is really questionable. A viable alternative is represented by the use of the scenario earthquakes, characterized at least in terms of magnitude, distance and faulting style, and by the treatment of complex source processes. Scenario-based seismic hazard maps are purely based on geophysical and seismotectonic features of a region and take into account the occurrence frequency of earthquakes on…
Like natural seismicity, induced seismicity caused by fluid injection also shows a power law size distribution, and its gradient b-value (ratio of small to large earthquakes) is often used for seismic hazard analysis. Despite well-known relationship that b-value is negatively correlated with differential stress for natural earthquakes, there is no understanding of the physical causes for b-value variations in injection-induced seismicity in the scale where the differential is nearly constant. We investigate a b-value dependence on the relative shear stress acting on existing fractures and show…
Antropogenic seismicity is one of the most important geomechanical hazard encountered in Polish deep copper mines. Obviously, it may have a negative impact on the peoples safety and the production process. In such circumstances, a number of both active and passive prevention measures have been implemented in the mines, at least partially. One of the most effective, applied for many years, active means used for seismic hazard reduction, is multi-faces blasting works which by assumption should result in release of strain energy accumulated in the rock mass by inducing seismic events in the areas…
Among different types of hazards associated with underground mining in Polish copper mines, one of the most dangerous is rock burst hazard. Having in mind that the depth of exploitation is getting deeper, this problem will likely get worse in the near future. This kind of hazard is connected inherently with seismic events. Controlled group blasting within a potentially unstable roof stratum is considered as an active method of rock burst prevention. A number of recorded seismic events can be clearly and directly explained by the blasting works effects. With electronic detonators, it is possibl…
Earthquakes are major hazards to humans, buildings and infrastructure. Early warning methods aim to provide advance notice of incoming strong shaking to enable preventive action and mitigate seismic risk. Their usefulness depends on accuracy, the relation between true, missed and false alerts, and timeliness, the time between a warning and the arrival of strong shaking. Current approaches suffer from apparent aleatoric uncertainties due to simplified modelling or short warning times. Here we propose a novel early warning method, the deep-learning based transformer earthquake alerting model (TE…
This paper aims at the analysis of seismic wave amplification in a deep alluvial basin in the city of Tunis in Tunisia. This sedimentary basin is 3000m wide and 350m deep. Since the seismic hazard is significant in this area, the depth of the basin and the strong impedance ratio raise the need for an accurate estimation of seismic motion amplification. Various experimental investigations were performed in previous studies to characterize site effects. The Boundary Element Method is considered herein to assess the parameter sensitivity of the amplification process and analyse the prevailing phe…
Constructing balanced datasets for predicting failure modes in structural systems under seismic hazards
Department of Civil and Environmental Engineering, University of California, Berkeley, United States（加州大学伯克利分校土木与环境工程系）；Department of Civil Systems Engineering, Ajou University, Suwon, Republic of Korea（全州大学土木系统工程系）
Declustering aims to divide earthquake catalogs into independent events (mainshocks), and dependent (clustered) events, and is an integral component of many seismicity studies, including seismic hazard assessment. We assess the effect of declustering on the frequency-magnitude distribution of mainshocks. In particular, we examine the dependence of the b-value of declustered catalogs on the choice of declustering approach and algorithm-specific parameters. Using the catalog of earthquakes in California since 1980, we show that the b-value decreases by up to 30% due to declustering with respect …
The recent 2014 eruption of the Ontake volcano in Japan recalled that hydrothermal fields of moderately active volcanoes have an unpredictable and hazardous behavior that may endanger human beings. Steam blasts can expel devastating ejecta and create craters of several tens of meters. The management of such hydrothermal hazards in populated areas is problematic because of their very short time constants. At present no precursory signal is clearly identified as a potential warning of imminent danger. Here we show how the combination of seismic noise monitoring and muon density tomography allows…
The Tohoku EQ (11th of March, 2011, M = 9.0) in Japan falsified the proposed EQ magnitude range (M = 7.0 - 8.5) of the same seismogenic regional area that had been determined by the compiled hazard maps, study of historical data, or other probabilistic methods while a larger magnitude (M > 9.0) had been proposed for all subduction zones. The observed discrepancy between the proposed EQ magnitude range and the actual one of the Tohoku EQ is studied in this work in terms of the cumulative seismic energy release of the study area and by the use of the Lithospheric Seismic Energy Flow Model (LSEFM…
We establish the equations which translate a conservation law for the problem of the seismic response of an above-ground structure (e.g., building, hill or mountain) of arbitrary shape and inquire whether both the implicit (formal) and explicit (numerical) solutions for the response obey this law for the case of a cylindrical, rectangular protuberance. Both the low-order (poor approximations of the response) as well as higher-order (supposedly better approximations) turn out to satisfy the conservation of flux relation, which means that the satisfaction of this relation is a necessary, but not…
A methodology for the performance-based seismic risk assessment of classical columns is presented. Despite their apparent instability, classical columns are, in general, earthquake resistant, as proven from the fact that many classical monuments have survived many strong earthquakes over the centuries. Nevertheless, the quantitative assessment of their reliability and the understanding of their dynamic behavior are not easy, because of the fundamental nonlinear character and the sensitivity of their response. In this paper, a seismic risk assessment is performed for a multidrum column using Mo…
This paper aims to investigate the effects of motion duration on the structural seismic demands, seeking potential correlations between motion durations and structural responses at several seismic intensity levels. Three seismic intensity levels with 100years, 475years, and 2475years earthquake return periods (RPs) are first considered for correlation computations. Spectrally matched ground motions are employed to isolate the contribution of duration from the effects of ground motion amplitudes and response spectral shape. Four single degree of freedom systems derived from four real reinforced…
The distribution of seismic moment is of capital interest to evaluate earthquake hazard, in particular regarding the most extreme events. We make use of likelihood-ratio tests to compare the simple Gutenberg-Richter power-law distribution with two statistical models that incorporate an exponential tail: the so-called tapered Gutenberg-Richter and the truncated gamma, when fitted to the global CMT earthquake catalog. The outcome is that the truncated gamma model outperforms the other two models. If simulated samples of the truncated gamma are reshuffled in order to mimic the time occurrence of …
The lack of offshore seismic data caused uncertainties associated to understating the behavior of future tsunamigenic earthquakes in the Makran Subduction Zone (MSZ). Future tsunamigenic events in the MSZ may trigger significant near-field tsunamis. Run-up heights in the near-field are controlled by the heterogeneity of slip over the rupture area. Considering a non-planar geometry for the Makran subduction zone, a range of random k^{-2} slip models were generated to hypothesize rupturing on the fault zone. We model tsunamis numerically and assess probabilistic tsunami hazard in the near-field …
Ground-motion prediction equations (GMPE) are essential in probabilistic seismic hazard studies for estimating the ground motions generated by the seismic sources. In low seismicity regions, only weak motions are available in the lifetime of accelerometric networks, and the equations selected for the probabilistic studies are usually models established from foreign data. Although most ground-motion prediction equations have been developed for magnitudes 5 and above, the minimum magnitude often used in probabilistic studies in low seismicity regions is smaller. Desaggregations have shown that, …
While wavefield reconstruction through weighted low-rank matrix factorizations has been shown to perform well on marine data, out-of-the-box application of this technology to land data is hampered by ground roll. The presence of these strong surface waves tends to dominate the reconstruction at the expense of the weaker body waves. Because ground roll is slow, it also suffers more from aliasing. To overcome these challenges, we introduce a practical workflow where the ground roll and body wave components are recovered separately and combined. We test the proposed approach blindly on a subset o…
2D ground motion at a soft viscoelastic layer/hard substratum site in response to SH cylindrical seismic waves radiated by deep and shallow line sources
A Discontinuous Galerkin Method for Simulating 3D Seismic Wave Propagation in Nonlinear Rock Models: Verification and Application to the 2015 Mw 7.8 Gorkha Earthquake
Water distribution systems (WDS) sustained severe damage in the past earthquakes. While previous studies investigated the seismic performance of buried water pipelines, the effects of corrosion on the pipeline seismic performance were ignored. The presence of corrosion on metallic pipeline walls aggravates seismic damage level because corrosion significantly reduces the pipeline strength. Most of the existing buried pipelines in the United States are aged and non-ductile metallic pipelines, which are vulnerable to seismic loading. To ensure continuous and smooth water supply to communities dur…
Noises are common events in seismic reflection data that have very striking features in seismograms, affecting seismic data processing and interpretation. Noise attenuation is an essential phase in seismic processing data, usually resulting in seismic interpretation improvement that enhances the signal to noise ratio. Groundroll presence is the major fashion of significant noise in the land seismic survey. It is a type of coherent noise present in seismograms that appears as linear events, in most cases overlapping the reflections and probably making it challenging to recognize. There are seve…
Structured soils with regular meshes of metric size holes implemented in first ten meters of the ground have been theoretically and experimentally tested under seismic disturbance this last decade. Structured soils with rigid inclusions embedded in a substratum have been also recently developed. The influence of these inclusions in the ground can be characterized in different ways: redistribution of energy within the network with focusing effects for seismic metamaterials, wave reflection, frequency filtering, reduction of the amplitude of seismic signal energy, etc. Here we first provide some…
