The Mdesign for engineering applications of Neo-Deterministic Seismic Hazard Assessment (NDSHA) within the China Seismic Experimental Site (CSES)

<p>For the concept of next-generation Early Earthquake Warning (EEW), the core idea is to combine EEW with seismic hazard assessment. In other words, to perform rapidly the computation of seismic hazard after the occurrence of an earthquake is detected and then to issue accurate warning, including lead time and potential seismic hazard level, to different end-users, e.g., railway system, working nuclear power plants and precision surgery in progress. We propose a scenario-based EEW by using the physics- and scenario-based hazard assessment, well known as Neo-deterministic Seismic Hazard Assessment (NDSHA). NDSHA can reliably compute the physically possible maximum ground motion response, including Maximum Credible Earthquakes (MCEs). In the framework of NDSHA, the general unit of processing time ranges from minutes to seconds, depending on the size of the study area and on the amount of computations. When the structural spectral information is available, the processing time significantly drops to a few seconds. Accordingly, a NDSHA scenario-based EEW relies on a hazard database, made by a collection of Modified Mercalli Intensity (MMI) maps, prepared and stored in advance. The establishment of such a hazard database is to consider all possible earthquake scenarios around target source zones based on now-available geophysical knowledge. Taking Xianshuihe (XSH) fault as an example, the six steps of the procedure to build the necessary hazard database could be the following: (1) definition of seismogenic zone; (2) definition of the first scenario source; (3) determination of source parameters; (4) determination of structural models; (5) computation of synthetic seismograms from the first source; (6) repeat (1) ~ (5), to travel all sources. Steps 1 to 6 allows us to obtain final (3264 in our case) results, i.e., the MMI maps for the adopted earthquake scenarios, which should be well representative of the potential earthquakes related to XSH.</p><p>As a first-order approximation in the construction of the hazard database, we assigned a characteristic focal mechanism for each cellular scenario earthquake. Once the hazard database is available, effective warning can be quickly issued to different end-users by selecting the suitable MMI map in the hazard database.</p>

Seismic hazard assessment (SHA) and associated risks (SRs) require necessarily an adequate understanding of earthquake distribution in magnitude, space, and time at regional scale. The Neo-Deterministic Seismic Hazard Assessment (NDSHA) is the innovative multi-disciplinary scenario-physics-based approach for reliable evaluation of seismic hazard and risks, which have been developed to overcome evident shortcomings of the outdated and very often wrong Probabilistic Seismic Hazard Analysis (PSHA). The NDSHA applications in many countries worldwide (Panza et al., 2021) pass intensive testing by instrumental and historical evidence, as well as by realistic modelling of scenario earthquakes. NDSHA results confirm reliable and effective input for mitigating object-oriented SRs. We applied two agents of the NDSHA synergy, i.e. Unified Scaling Law for Earthquakes (USLE) and anisotropic propagation of seismic effect, to evaluate SRs for the railway infrastructure in the Lake Baikal region.USLE states that the logarithm of expected annual number of earthquakes of magnitude M or larger in an area of linear dimension L follows within the magnitude range [M– , M+] the relationship log N(M, L) = A + B×(5 − M) + C×log L, where A, B and C are constants. Naturally, A and B are analogous to the a- and b-values of the classical Gutenberg-Richter relationship (G-RR), while C compliments to G-RR with an estimate of local fractal dimension of earthquake epicentres allowing for realistic rescaling seismic hazard to the size of exposure at risk. USLE implies that the maximum magnitude MX expected with p% chance in T years can be obtained from N(MX, L) = p%, then used for estimating ground shaking effect.We used as essentials (i) macroseismic intensity scale that provides a robust estimate for realistic modelling of maximal potential ground shaking in assessment of regional seismic hazard and associated risks and (ii) anisotropic propagation of seismic effect that is evidently following, in most cases of large earthquakes, dominant direction of active faults nearby epicentre and apply these to the earthquake catalogue compiled at the Baikal Division of the Geophysical Survey, Federal Research Centre of the Russian Academy of Sciences (http://www.seis-bykl.ru/), Active Faults of Eurasia Database (http://neotec.ginras.ru/database.html) and data on railroads from the OpenStreetMap project (https://www.openstreetmap.org).We present the SRs for railway lines, hubs and tunnels in the Lake Baikal region based on the maps of maximum macroseismic intensity expected in a period of 50 years with a probability of 10%, 5% and 1% (Nekrasova&Kossobokov, 2022) and different model vulnerability functions attributed to the exposed infrastructure elements of different kind.The study is carried on in the framework of the Russian State Task of Scientific Research Works of IEPT RAS and IPE RAS. ReferencesNekrasova A, Kossobokov V (2022) Seismic risk assessment for the infrastructure in the regions adjacent to the Russian Federation Baikal–Amur Mainline based on the Unified Scaling Law for Earthquakes. Natural Hazards, https://doi.org/10.1007/s11069-022-05750-9Panza G, Kossobokov V, De Vivo B, Laor E (Eds) (2021) Earthquakes and Sustainable Infrastructure: neo-deterministic (NDSHA) approach guarantees prevention rather than cure. Elsevier, xxv, 672 p. https://doi.org/10.1016/C2020-0-00052-

Chapter 26 - Application of neo-deterministic seismic hazard assessment to India

NDSHA: A new paradigm for reliable seismic hazard assessment

Seismic hazard assessment (SHA) and evaluation of seismic risks (SRs) require an adequate understanding of the actual distribution of earthquakes over magnitude, space, and time ranges. The standard probabilistic seismic hazard analysis (PSHA) has never been subjected to unbiased scrutiny before publication of the final maps, which are misleading to unacceptable human and economic losses; this has been proven on many occasions, including the most recent cases – 6 February 2023 (Turkey), 8 September 2023 (Morocco), and 1 January 2024 (Japan).  Neo-deterministic seismic hazard assessment (NDSHA) methodologies have been developed to improve the reliability and accuracy of reproducible seismic hazard maps. In the last decade, the application of NDSHA in many regions of the world has confirmed the availability of reliable and effective input for mitigating earthquake risks (Panza et al., 2021). NDSHA results have passed intensive testing by historical evidence and realistic modelling of scenario earthquakes.We used two agents of the NDSHA synergy, i.e. Unified Scaling Law for Earthquakes (USLE) and anisotropic propagation of seismic effect, to evaluate SRs for the Lake Baikal regional railroad system on the basis of seismic hazard maps of maximum macroseismic intensity expected in 50 years with 10%, 5%, and 1% chance of exceedance. Specifically, we employed the regional layers from the widely used crowdsourced dataset, Open Street Map, which features global coverage. These layers include infrastructure elements such as tracks, bridges, and tunnels.We have extended our analysis of seismic risk assessment for the Lake Baikal Region railway system presented earlier (Nekrasova et al., 2024) and compare our results with the SR evaluations based on the General Seismic Zonation 2016 and Global Earthquake Model 2018 final hazard maps at identical levels of probability of exceedance.A comparison of PSHA and NDSHA approaches in application to the Lake Baikal railway system disclose significant overestimation of the reconstruction costs for expected state of extreme damage (Hazus state standard ds5 - Complete) due to earthquakes, if GSZ2016 or GEM2018 and not USLE modelling is used. In particular, the significant discrepancy in the area of expected ground shaking of macroseismic intensity VIII or higher that may damage the railroad tracks, bridges, and tunnels leads to a dramatic difference in the seismic risk values measured in arbitrary units of currency.Our results are presented for academic purposes only. Evidently, more adequate though significantly more complex procedures involving more complicated procedures of convolution of seismic hazard, exposures, and their vulnerability are required when addressing realistic and practical assessment of seismic risks. Such assessments should involve experts in seismology, earthquake engineering, social sciences, and economics.ReferencesNekrasova A, Kossobokov V, Podolskaia E (2024) Regional seismic risk assessment based on the Unified Scaling Law for Earthquakes: The Lake Baikal railway system. Soil Dynamics and Earthquake Engineering 177, 108402. https://doi.org/10.1016/j.soildyn.2023.108402Panza G, Kossobokov V, De Vivo B, Laor E (Eds) (2021) Earthquakes and Sustainable Infrastructure: neo-deterministic (NDSHA) approach guarantees prevention rather than cure. Elsevier. Paperback ISBN: 9780128235034, eBook ISBN: 9780128235416, xxv, 672 p. https://doi.org/10.1016/C2020-0-00052-

The Neo-Deterministic Seismic Hazard Assessment (NDSHA) procedure for the development of seismic hazard maps at the regional scale has been validated by all the events occurred in regions where NDSHA maps were available at the time of the quake. NDSHA method reliably and realistically simulates the wide suite of earthquake ground motions that may impact civil populations as well as their heritage buildings. The scenario based NDSHA’s modeling technique is developed from comprehensive physical knowledge of: (i) the seismic source process; (ii) the propagation of earthquake waves; and (iii) their combined interactions with site effects. A useful safety factor conceptually similar to the ones used in structural engineering can be used to set the estimated magnitude of the scenario events. Using the signals generated by NDSHA, well rooted on the fundamental laws of physics and on the experimental evidence, a number of possible structural engineering approaches become available.

Neo-deterministic seismic hazard assessment and earthquake occurrence rate

Current computational resources and physical knowledge of the seismic wave generation and propagation processes allow for reliable numerical and analytical models of waveform generation and propagation. From the simulation of ground motion, it is easy to extract the desired earthquake hazard parameters. Accordingly, a scenario-based approach to seismic hazard assessment has been developed, namely the neo-deterministic seismic hazard assessment (NDSHA), which allows for a wide range of possible seismic sources to be used in the definition of reliable scenarios by means of realistic waveforms modelling. Such reliable and comprehensive characterization of expected earthquake ground motion is essential to improve building codes, particularly for the protection of critical infrastructures and for land use planning. Parvez et al. (Geophys J Int 155:489–508, 2003) published the first ever neo-deterministic seismic hazard map of India by computing synthetic seismograms with input data set consisting of structural models, seismogenic zones, focal mechanisms and earthquake catalogues. As described in Panza et al. (Adv Geophys 53:93–165, 2012), the NDSHA methodology evolved with respect to the original formulation used by Parvez et al. (Geophys J Int 155:489–508, 2003): the computer codes were improved to better fit the need of producing realistic ground shaking maps and ground shaking scenarios, at different scale levels, exploiting the most significant pertinent progresses in data acquisition and modelling. Accordingly, the present study supplies a revised NDSHA map for India. The seismic hazard, expressed in terms of maximum displacement (Dmax), maximum velocity (Vmax) and design ground acceleration (DGA), has been extracted from the synthetic signals and mapped on a regular grid over the studied territory.

The Neo Deterministic Seismic Hazard Assessment (NDSHA) is the innovative multi‐disciplinary scenario‐physics‐based approach for the evaluation of seismic hazard and risks. When an earthquake occurs, the ground shaking does not depend on its likelihood according to the widespread Probabilistic Seismic Hazard Analysis (PSHA), which estimates are too often wrong. An “unlikely” earthquake can occur at any time and, sooner or later, with 100% probability. Therefore, from a perspective of safety, it is essential that infrastructure and public installations are designed so as to resist future strong earthquakes. NDSHA has proven to both reliably and realistically simulate comprehensive sets of hazardous ground motions in many regions worldwide. Today NDSHA is gaining momentum in spreading worldwide an innovative Paradigm of Reliable Seismic Hazard Assessment (RSHA) that should ultimately change mind‐sets of scientific and engineering communities from disbelief in probabilistic forecasting to optimistic challenging issues of neo‐deterministic predictability of Natural Hazards and Risks.

Chapter 9 - Spreading NDSHA application from Italy to other areas

Chapter 18 - NDSHA achievements in Central and South-eastern Europe

A New Paradigm (data driven and not like the currently model driven) is needed for Reliable Seismic Hazard Assessment RSHA. Neo-Deterministic Seismic Hazard Assessment (NDSHA) integrates earthquake geology, earthquake science, and particularly earthquake physics to finally achieve a New (and needed) Paradigm for Reliable Seismic Hazard Assessment RSHA.Although observations from many recent destructive earthquakes have all confirmed the validity of NDSHA’s approach and application to earthquake hazard forecasting-nonetheless damaging earthquakes still cannot yet be predicted with a precision requirement consistent with issuing a red alert and evacuation order to protect civil populations. However, intermediate-term (time scale) and middle-range (space scale) predictions of main shocks above a pre-assigned threshold may be properly used for the implementation of low-key preventive safety actions, as recommended by UNESCO in 1997. Furthermore, a proper integration of both seismological and geodetic information has been shown to also reliably contribute to a reduction of the geographic extent of alarms and it therefore defines a New Paradigm for TimeDependent Hazard Scenarios: Intermediate-Term (time scale) and Narrow-Range (space scale) Earthquake Prediction.

A New Paradigm (data driven and not like the currently model driven) is needed for Reliable Seismic Hazard Assessment RSHA. Neo-Deterministic Seismic Hazard Assessment (NDSHA) integrates earthquake geology, earthquake science, and particularly earthquake physics to finally achieve a New (and needed) Paradigm for Reliable Seismic Hazard Assessment RSHA.Although observations from many recent destructive earthquakes have all confirmed the validity of NDSHA’s approach and application to earthquake hazard forecasting-nonetheless damaging earthquakes still cannot yet be predicted with a precision requirement consistent with issuing a red alert and evacuation order to protect civil populations. However, intermediate-term (time scale) and middle-range (space scale) predictions of main shocks above a pre-assigned threshold may be properly used for the implementation of low-key preventive safety actions, as recommended by UNESCO in 1997. Furthermore, a proper integration of both seismological and geodetic information has been shown to also reliably contribute to a reduction of the geographic extent of alarms and it therefore defines a New Paradigm for TimeDependent Hazard Scenarios: Intermediate-Term (time scale) and Narrow-Range (space scale) Earthquake Prediction.

<p>Seismic hazard assessment requires an adequate understanding the earthquake distribution in magnitude, space, and time ranges. Laking data for a period of several thousand years makes probabilistic approach to estimating the recurrence time of hazardous ground shaking unreliable and misleading. In spite of theoretical flaws and actual failures on practice, the probabilistic seismic hazard assessment (PSHA) maps keep being actively used both at global and national scales. In recent decades, alternative methodologies have been developed to improve the reliability and accuracy of reproducible seismic hazard maps that pass intensive testing by historical evidence and realistic modelling of scenario earthquakes. In particular, the neo-deterministic seismic hazard assessment (NDSHA) confirms providing reliable and effective input for mitigating object-oriented earthquake risks. The unified scaling law for earthquakes (USLE) is a basic part of NDSHA that generalizes application of the Gutenberg-Richter law (G-RL). The USLE states that the logarithm of expected annual number of earthquakes of magnitude M in an area of linear size L within the magnitude range [M– , M+] follows the relationship log N(M, L) = A + B×(5 − M) + C×log L, where A, B, and C are constants.  Naturally, A and B are analogous to the classical a- and b-values, while C compliments to G-RL with the estimate of local fractal dimension of earthquake epicentres allowing for realistic rescaling seismic hazard to the size of exposure at risk. USLE implies that the maximum magnitude MX expected with p% chance in T years can be obtained from N(MX, L) = p%, then used for estimating and mapping ground shaking parameters by means of the NDSHA algorithms. So far, the reliable USLE based seismic hazard maps tested by historical evidence have been plotted for a number of regions worldwide. We present the USLE based maps of MX computed at earthquake-prone cells of a regular grid, as well as the adapted NDSHA estimates of seismic hazard and risks for social and infrastructure exposures in the regions adjacent to the Russian Federation Baikal–Amur Mainline. The study supported by the Russian Science Foundation Grant No. 20-17-00180.</p>

Regional seismic risk assessment based on the Unified Scaling Law for Earthquakes: The Lake Baikal railway system