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This article presents the findings of a study on the directionality effect observed in strong motion records. We set out to establish ratios between several seismic intensity measures that depend on sensor orientation (e.g., GMar, Larger) and others that are orientation-independent (e.g., RotDpp, GMRotDpp, and GMRotIpp), with the intention of proposing multiplicative correction factors. The analysis included an evaluation of the impact of site conditions, ground motion intensity, earthquake magnitude, and hypocentral distance on these ratios. Following a concise overview of the directionality effects and the associated intensity measures, the Costa Rican Strong Motion Database, comprising a total of 4199 horizontal accelerograms (two components), was employed to determine the correction factors. The analysis was carried out for 5% damped response spectra within the 0.01–5 s period range. The study focuses on orientation-independent intensity measures that are derived by combining the maximum values from the recorded motions. In the comprehensive analysis of the complete database, a trend was observed between these intensity measures and the magnitude of the earthquake along with the hypocentral distance. Specifically, records from earthquakes with greater magnitudes exhibited a lower maximum spectral response to the geometric mean of the response spectra of the as-recorded (ar) components ratio (RotD100/GMar), similar to records from earthquakes with larger hypocentral distances. Based on these findings, a proposal was put forth to estimate RotD100 values using GMar values. This ratio can prove useful in transforming data from previous seismic hazard studies, including those applied in many seismic codes, and in defining the maximum anticipated seismic intensity for design purposes in a more straightforward manner. [ABSTRACT FROM AUTHOR]

The main disadvantages of selected elements of seismicity modeling for composing the General Seismic Zoning maps are considered in the framework of a probabilistic approach. We proposed a method that should provide more precise assessment of probable future seismicity after the improvements of the disadvantages. A stochastic seismicity model is suggested for the first time as a synthetic earthquake catalog, which is generated for an arbitrary conditional period and which reproduces the properties of the catalog of factual earthquakes including spatiotemporal grouping. The verification method of seismicity models is suggested to check the correspondence of the models to the primary data and the assessment of the predictive efficiency of the models and to compare various models based on these characteristics. [ABSTRACT FROM AUTHOR]

Effective site characterization in highly urbanized coastal lowlands requires accurate stratigraphic and geophysical investigations. In these regions, which typically host shallowly buried paleovalley systems formed in response to Quaternary glacio‐eustatic fluctuations, the marked lithologic contrast between soft sediment paleovalley fills and the adjacent, stiff substrate has the potential to modify earthquake motions, and assessment of critical parameters, such as shear wave velocities (VS) and resonance frequencies (f), should be coupled with detailed stratigraphic architecture. To evaluate the potential of the microtremor horizontal‐to‐vertical spectral ratio (mHVSR) for paleovalley recognition and mapping, we performed mHVSR measurements along the Adriatic coastal plain of Italy, where two paleovalley systems (Pescara and Manfredonia) have been recently identified. In both areas, we detected rapid lateral variations in resonance frequencies and highlighted laterally continuous impedance contrasts. Relying on a robust stratigraphic framework, we carefully evaluated the relation between geological and geophysical data and identified the stratigraphic surfaces responsible for the observed resonances. We derived VS models for the sediment fill, reconstructing the geometry of the two buried paleovalleys. We address the importance of evaluating the geological context when designing microzonation studies, for a reliable interpretation of changes in resonance frequencies. Plain Language Summary: When earthquakes occur, buildings shake differently based on several factors, including seismic wave velocity, natural resonance frequencies, and local geological characteristics. Beneath modern coastal lowlands, the presence of paleovalley systems can significantly modify the ground motion. Identification of these buried bodies is therefore essential to assess and reduce seismic hazard. Paleovalleys are shallow incisions formed under periods of fluvial erosion in response to Quaternary climate fluctuations, and subsequently filled with very soft clay. These bodies are found worldwide, and do not have any geomorphological evidence, making their recognition challenging. Geologists typically use expensive sediment core analysis to identify paleovalleys, but this method can only provide spotty information. Geophysical exploration techniques that rely on microtremors (small vibrations on the Earth) can complement mapping of these buried bodies. In this work, we tested this technique in Pescara and Mafredonia (Adriatic coastal plain, Italy), providing dense information about paleovalley geometries and geophysical parameters crucial for predicting how the ground will shake during an earthquake. This study also highlights the importance of integrating disciplines to improve our understanding of subsoil and to design future studies to mitigate seismic hazards. Key Points: Paleovalley fills are key sediment bodies made up of soft clay, tens of m thick and few km wide, buried beneath coastal lowlands worldwideMicrotremor‐based paleovalley profiles and stratigraphic cross‐sections exhibit strong similarityMicrotremor can provide shear wave velocities and resonance frequencies of paleovalleys, key parameters for seismic hazard mitigation [ABSTRACT FROM AUTHOR]

The metropolitan community of Montreal (MMC) is located in Eastern Canada and included in the western Quebec seismic zone characterized by shallow crustal earthquakes and moderate seismicity. Most of the urbanized areas are settled close to the Saint-Lawrence River and its tributaries and within the region, delimiting the extension of the clay deposits from the Champlain Sea. The influence of these recent and soft deposits on seismic waves has been observed after the 1988 M5.8 Saguenay earthquake and has proven to be crucial in seismic hazard analysis. The shear-wave velocity Vs averaged over the 30 m of soil, abbreviated Vs30, is one of the most used parameters to characterize the site condition and its influence on seismic waves. Since 2000, a site condition model has been developed for the municipalities of Montreal and Laval, combining seismic and borehole data for risk mitigation purposes. The paper presents an extended version of the Vs30 mapping for the entire region of the MMC, which accounts for half of the population of Quebec, including additional ambient noise recordings, recently updated borehole datasets, geological vector map and unpublished seismic refraction data to derive Vs profiles. The estimated Vs30 values for thousands of sites are then interpolated on a regular grid of 0.01 degrees using the inverse distance weighted interpolation approach. Regions with the lowest estimated Vs30 values where site amplification could be expected on seismic waves are in the Northeastern part and in the Southwest of the MMC. The map expresses in terms of site classes is compared with intensity values derived from citizen observations after recent felt. In general, the highest reported intensity values are found in regions with the lowest Vs30 values on the map. Areas where this rule does not apply, should be investigated further. This site condition model can be used in seismic hazard and risk analysis. [ABSTRACT FROM AUTHOR]

Induced seismicity has been a serious problem for many coal mines in the Upper Silesian Coal Basin in Poland for many decades. The occurring mining tremors of the rock mass generate seismic vibrations that cause concern to the local population and in some rare cases lead to partial damage to buildings on the surface. The estimation of peak ground acceleration values caused by high energy mining seismic tremors is an important part of seismic hazard assessment in mining areas. A specially designed bootstrapping procedure has been applied to estimate the ground motion prediction model and makes it possible to calculate the confidence intervals of these peak ground acceleration values with no assumptions about the statistical distribution of the recorded seismic data. Monte Carlo sampling with the replacement for 132 seismic records measured for mining seismic tremors exceeding 150 mm/s2 have been performed to estimate the mean peak ground acceleration values and the corresponding upper limits of 95% confidence intervals. The specially designed bootstrap procedure and obtained ground motion prediction model reflect much better the observed PGA values and therefore provide more accurate PGA estimators compared to the GMPE model from multiple regression analysis. The bootstrap analysis of recorded peak ground acceleration values of high-energy mining tremors provides significant information on the level of seismic hazard on the surface infrastructure. A new tool has been proposed that allows for more reliable determination of PGA estimators and identification in the areas in coal mines that are prone to high-energy seismic activity. [ABSTRACT FROM AUTHOR]

The 1641 Dehkhwargan-Tabriz earthquake (Ms 6.8) is the only destructive earthquake to have occurred in Azarshahr-Khosrowshahr-Osku region of northwestern Iran. Ambiguities regarding the causative fault of this earthquake were a motivation to someway declare its mechanism. In this study, by conducting a field survey in an area between Tabriz and Azarshahr, and use of satellite imagery and aerial photographs, we provide geologic and geomorphic indications to identify the poorly known Azarshahr-Tabriz fault zone (ATF), which passes through the meizoseismal region of the 1641 earthquake. Our observations highlight the presence of a sinistral active fault zone that extends ~40 km in length from south of Tabriz to the northeast and north of Azarshahr to the southwest. The ATF is a structural assemblage of several fault strands with a variety of extensional and compressional mesoscale structures. We estimated slip rates ranging from ~0.01 mm yr-1 to <1 mm yr-1, based on drainage offset measurements, which demonstrate a relatively stable tectonic environment located immediately south of the well-known seismically active dextral North Tabriz fault. [ABSTRACT FROM AUTHOR]

After the 1999 Marmara earthquake, serious damages occurred in some of the drinking water networks of Sakarya province, and almost all of the sewerage networks became inoperable. In this study, the vulnerability of buried pipes, which constitute a large part of the potable water supply and distribution networks of the infrastructure systems of Sakarya province, against seismic hazards were analyzed by the Hazard US (HAZUS) method. The maximum ground velocity used in the analysis of the vulnerability of buried pipes against possible earthquakes was determined with the help of classical probabilistic earthquake hazard analysis. Soil classes used in vulnerability analysis were calculated with the help of seismic data taken from 2044 points throughout the province. Sakarya province potable water pipe inventory was created and vulnerability parameters were defined for all pipes with the help of geographic information systems. The HAZUS method, which is frequently used in the literature, was used for pipe vulnerability analysis. As a result of the analysis, damage repair rates expressing the vulnerability of all pipes were obtained and the pipes were classified according to their damage repair rates. [ABSTRACT FROM AUTHOR]

For the first time, a numerical comparison of the General Seismic Zoning (GSZ) maps with the effect of earthquakes that actually occurred after the publication of the maps was carried out. The area of zones of expected intensity on the GSZ map is compared with the area of isoseists from actual earthquakes. It turned out that the isoseist area is on average by an order less than expected according to the GSZ. This paper describes possible reasons for such an overestimation and proposes ways to improve seismic hazard assessments. [ABSTRACT FROM AUTHOR]

Lobate scarps (thrust faults) in the lunar south polar region (90°–60°S) provide important insights into tectonic history, seismicity, and seismic hazard potential of landing sites. In this study, we discovered 75 new lobate scarps and >500 segments, exhibiting latitudinal variation of geometry and movement directions. Formation ages of 141 prominent scarp segments show fault growth rates and directions, decreasing ages from south pole to mid‐latitude, continuous tectonic activity in the last 100 million years with a peak around 10 Ma, seismic resetting of ages, and timings of global contraction. The scarps are capable of producing small‐medium size moonquakes within 5–10 km depths. The deterministic seismic hazard analysis, considering occurrence of MW 1–4 shallow moonquakes along the scarps in the next few decades, and their seismic ground motion characteristics, suggests variable levels of potential seismic risk at the Artemis candidate landing regions and further probabilistic seismic hazard analysis is necessary. Plain Language Summary: National Aeronautics and Space Administration prepares for a long‐term human and robotic Artemis missions to the lunar south pole. In this study, we determined whether the Artemis candidate landing regions near the south pole is safe from the seismic hazard that may potentially originate from the lobate scarps (thrust faults) present in the lunar south polar region (90°–60°S). We discovered 75 new lobate scarps containing >500 segments. The lobate scarps exhibit a latitudinal variation of orientations and movement directions. The scarps are absent within 100 km radius from the south pole. The formation ages of 141 prominent scarps reveal that they were formed in the last 100 million years with a peak of tectonic activity around 10 Ma. A pole‐ward increase of scarp ages is also noted. A few scarps allowed estimation of lateral fault growth rates and directions. The lobate scarp segments are capable of producing MW 3.5–6.5 shallow moonquakes at focal depths of <5–10 km. Considering occurrence of MW 1–4 shallow moonquakes along these scarps in the next few decades and their seismic ground motion characteristics, we demarcated potential seismic hazard zones and seismically low risk areas, at the Artemis candidate landing regions. Key Points: Hundreds of new lobate scarps exhibiting latitudinal variation of geometry, kinematics and ages are found in the lunar south polar regionScarp ages indicate fault growth durations and rates, continuous tectonic activity in the last 100 million years and seismic resurfacingLobate scarps are major sources of seismicity posing variable levels of potential seismic risk at the Artemis candidate landing regions [ABSTRACT FROM AUTHOR]

A strong motion monitoring network records data that provide an excellent way to study how source, path, and site effects influence the ground motion, specifically in the near-source area. Such data are essential for updating seismic hazard maps and consequently building codes and earthquake-resistant design. This paper aims to present the Italian Strong Motion Network (RAN), describing its current status, employment, and further developments. It has 648 stations and is the result of a fruitful co-operation between the Italian government, regions, and local authorities. In fact, the network can be divided into three sub-networks: the Friuli Venezia Giulia Accelerometric Network, the Irpinia Seismic Network, and all the other stations. The Antelope software automatically collects, processes, and archives data in the data acquisition centre in Rome (Italy). The efficiency of the network on a daily basis is today more than 97%. The automatic and fast procedures that run in Antelope for the real-time strong motion data analysis are continuously improved at the University of Trieste: a large set of strong motion parameters and correspondent Ground Motion Prediction Equations allow ground shaking intensity maps to be provided for moderate to strong earthquakes occurring within the Italian territory. These maps and strong motion parameters are included in automatic reports generated for civil protection purposes. [ABSTRACT FROM AUTHOR]

Recently developed region-specific GMPEs are used for a comprehensive seismic hazard analysis (SHA) of the North and Central Himalayas (NCH) using a probabilistic approach considering two source models. Vulnerable seismic sources in the areas are identified based on the Seismotectonic Atlas (Dasgupta et al. 2000), published by the Geological Survey of India. An up to date, homogenized and declustered earthquake catalogue is compiled from various sources, with earthquake data since 250 BC, to create a new digitized seismotectonic representation of the region. Regional seismic zones having similar seismicity are recognized based on the Gutenberg-Richter (GR) parameters and the region is delineated into 5 seismic zones. The study area is divided into grids of size 0.05° × 0.05° and the hazard in terms of Peak Ground Acceleration (PGA) at the centre of each grid point is estimated and presented as hazard maps for individual seismic sources, maximum of all sources, and average of both sources. From the current study, it could be concluded that the PGA estimated in the regions is comparatively higher than what is reported in the codal provisions for seismic zonation and estimation of design horizontal acceleration for the region. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the Himalayan region is under the threat of earthquakes of magnitude nine or larger. These estimates are based on comparisons of the geodetically inferred moment deficit rate with the seismicity of the region. However, these studies did not account for the physics of fault slip, specifically the influence of frictional barriers on earthquake rupture dynamics, which controls the extent and therefore the magnitude of large earthquakes. Here we combine an improved probabilistic estimate of moment deficit rate with results from dynamic models of the earthquake cycle to more fully assess the seismogenic potential of the Main Himalayan Thrust (MHT). We propose a straightforward and efficient methodology for incorporating outcomes of physics‐based earthquake cycle models into hazard estimates. We show that, accounting for uncertainties on the moment deficit rate, seismicity and earthquake physics, the MHT is prone to rupturing in Mw 8.7 earthquakes every T > 200 years. Plain Language Summary: Recent studies have shown that the Himalayan region is under the threat of earthquakes of magnitude nine or larger. To draw such estimates, researchers compare how surface deformation translates as potential slip on a fault with the rate at which measured earthquakes occur. In short, these studies only consider the kinematics of the region and compare current seismicity with how much earthquakes are to be expected in the future considering the statistics of earthquakes do not change with time. Therefore, these studies do not take advantage of the recent advances in fault physics. Here, we compare surface deformation rates, earthquake catalogs and numerical simulations of the earthquake cycle to assess the seismogenic potential of the Main Himalayan Thrust (MHT). Our methodology incorporates outcomes of physics‐based earthquake cycle simulations into hazard estimates. We show that, accounting for all available uncertainties, the MHT is prone to rupturing in Mw 8.7 earthquakes every T > 200 years. Key Points: Combine probabilistic estimate of moment deficit rate with results from earthquake cycle dynamic models to assess the seismogenic potentialStraightforward and efficient methodology for incorporating outcomes of physics‐based earthquake cycle models into hazard estimatesMain Himalayan Thrust prone to rupturing in M8.7, accounting for uncertainties on moment deficit rate, seismicity and earthquake physics [ABSTRACT FROM AUTHOR]

Recent studies have shown that the Himalayan region is under the threat of earthquakes of magnitude nine or larger. These estimates are based on comparisons of the geodetically inferred moment deficit rate with the seismicity of the region. However, these studies did not account for the physics of fault slip, specifically the influence of frictional barriers on earthquake rupture dynamics, which controls the extent and therefore the magnitude of large earthquakes. Here we combine an improved probabilistic estimate of moment deficit rate with results from dynamic models of the earthquake cycle to more fully assess the seismogenic potential of the Main Himalayan Thrust (MHT). We propose a straightforward and efficient methodology for incorporating outcomes of physics‐based earthquake cycle models into hazard estimates. We show that, accounting for uncertainties on the moment deficit rate, seismicity and earthquake physics, the MHT is prone to rupturing in Mw 8.7 earthquakes every T > 200 years. Plain Language Summary: Recent studies have shown that the Himalayan region is under the threat of earthquakes of magnitude nine or larger. To draw such estimates, researchers compare how surface deformation translates as potential slip on a fault with the rate at which measured earthquakes occur. In short, these studies only consider the kinematics of the region and compare current seismicity with how much earthquakes are to be expected in the future considering the statistics of earthquakes do not change with time. Therefore, these studies do not take advantage of the recent advances in fault physics. Here, we compare surface deformation rates, earthquake catalogs and numerical simulations of the earthquake cycle to assess the seismogenic potential of the Main Himalayan Thrust (MHT). Our methodology incorporates outcomes of physics‐based earthquake cycle simulations into hazard estimates. We show that, accounting for all available uncertainties, the MHT is prone to rupturing in Mw 8.7 earthquakes every T > 200 years. Key Points: Combine probabilistic estimate of moment deficit rate with results from earthquake cycle dynamic models to assess the seismogenic potentialStraightforward and efficient methodology for incorporating outcomes of physics‐based earthquake cycle models into hazard estimatesMain Himalayan Thrust prone to rupturing in M8.7, accounting for uncertainties on moment deficit rate, seismicity and earthquake physics [ABSTRACT FROM AUTHOR]

Peninsular Malaysia is susceptible to large magnitude earthquakes induced by the regional sources as it is surrounded by countries that are known for their active seismicity. Tremors were felt in Penang Island of Pulau Pinang due to earthquake events in Sumatra, Indonesia in 2005 and 2009. Presence of cracks on buildings in the island was reported caused by the earthquake on 2nd November 2002. The tsunami that hit the island on 26 December 2004 was the aftermath of the Great Sumatra-Andaman earthquake with magnitude 9.1. The investigation of earthquake risks ensures that the effect of earthquake disasters in the inclined region can be reduced effectively. This paper aims to provide a comprehensive seismic hazard assessment in Penang Island by analysing the predominant natural frequency distribution in Balik Pulau through a passive seismic survey method known as horizontal-to-vertical spectral ratio (HVSR) and evaluating the ground motion throughout the island using probabilistic seismic hazard assessment (PSHA) approach. The natural frequencies of Balik Pulau mostly falls in the range of 3 to 4 Hz which is associated with loose deposits and stiff soil layer. The amplification factor extracted from the HVSR curves ranges approximately 4 to 5. The minimum ground motions estimated for a fixed intensity in 50 years for Penang Island is 0.006 g1 and can reach up to 0.025 g. While the minimum ground motions for a fixed return period of 98 years in 50 years is 0.016 g with maximum of 0.035 g. [ABSTRACT FROM AUTHOR]

We have investigated the time-dependent seismicity model of the earthquake occurrence on a regional basis through the North Anatolian Fault Zone (NAFZ). To that end, the studied region has been subdivided into 7 seismogenic zones considering the seismotectonic criteria, and then regional time and magnitude predictable (RTIMAP) model has been performed. Intervened times and magnitudes of main shocks produced in each zone have predictive properties defined by the RTIMAP. The probabilities of the next main shocks in 5 decades and the magnitudes of the next events have been estimated using the formation time and magnitude of the past events in the zones. In the second step of the study, we have considered 17 settlements located on the NAFZ to perform point-based site-specific seismic hazard analyses and to determine the design spectra and earthquake parameters using updated Turkish Earthquake Hazard Map. Eigen value and static adaptive pushover analyses have been applied for the sample reinforced concrete building using the design spectra obtained from each settlement. This sample building has been modelled with the same structural characteristics (i.e. material strength, column and beams, applied loads, etc.) for all of the settlements. We have determined that the earthquake building parameters differ from each other which indicates the significance of site-specific seismicity characteristics on the building performance. [ABSTRACT FROM AUTHOR]

The French Central Seismological Bureau (BCSF) is celebrating its centenary this year. However, from the macroseismic studies point of view, which is the main activity of BCSF, it would be more accurate to celebrate its 92nd anniversary of activity. This is because between 1978 and 1986, macroseismic studies were assigned to the Geological and Mining Research Bureau (BRGM) owing to an obvious failure of BCSF to fulfill its mission. In this article, I aim to bring a new insight on this unfortunate, tragic episode by following two main actors of BCSF history: Edmond and Jean- Pierre Rothé, father and son. Through them I will relate the story of French macroseismic studies and, more broadly, French seismicity. In order to do so, I will focus on how they built themselves a full system of monitoring and processing earthquake data, and also on how together they owned all the macroseismic data in France for almost 60 years. I will explore how their dominance brought about the failure of BCSF after the collapse of the legitimacy of Rothé’s expertise at a time when earthquake issues were intertwined in nuclear industry stakes. This brings to light not only the history of French seismicity but also the vulnerability of seismic hazard assessment practices. [ABSTRACT FROM AUTHOR]

The Iranian plateau is located in the high seismicity belt. Earthquake can inflict severe loss of life and property, especially when they occur in densely populated areas. Therefore, seismic hazard evaluation is very essential to prevent the harmful effects. The region of the study is located in the northwest of Iran, between 43°-50° E longitude and 35.5°-40.5° N latitude. This city which is located in the center of East Azerbaijan province, has been ruined by terrible earthquakes, which is due to the presence of active faults in the region. Seismic hazard assessment similar to other seismology researches is very complicated due to the effect of different parameters in an earthquake occurring with uncertainty. The amount of uncertainty should be considered in a rational way. The fuzzy method is a suitable method that is used as a decision-making method for solving problems and modeling uncertainties and ambiguities. We used a fuzzy inference system, as the practice is based on uncertainty estimation of seismic hazard for Tabriz region. Peak ground Acceleration value is estimated for fuzzy Logic System in deterministic method 0.55g which is obtained from a seismic source with a Mmax=8.0 at a distance of 36.98 km of Tabriz city. The contour map of the peak ground acceleration throughout Tabriz city can help in urban planning. [ABSTRACT FROM AUTHOR]

To provide information towards understanding Taiwan's earthquake hazard and risk, the multi-disciplinary Taiwan Earthquake Model (TEM) project, supported by the Ministry of Sciences and Technology, had prepared and published a first version of seismic hazard assessment maps of Taiwan in 2016, together with an on-land seismogenic structure database of the island. In the years following the publication of this first version, we have constructed an updated version of this database. Seven structures were identified and added to the database. Based on additional information, we have also updated the structural parameters of four existing structures, as well as systematically updated the parameters of all structures to include more complete parameter uncertainties. This update of the database represents the most up-to-date information of seismogenic structures in Taiwan, and would provide better constraints for future seismic hazard assessment and mitigation studies. [ABSTRACT FROM AUTHOR]

Bayesian probability theory is an appropriate and useful method to estimate parameters in seismic hazard analysis. The analysis in Bayesian approaches is based on a posterior belief, also their special ability is to take into account the uncertainty of parameters in probabilistic relations and a priori knowledge. In this study, we used the program for seismic hazard Bayesian estimate which was elaborated by Alexey Lyubushin. Our study is the next in the sequence of applications of this software to seismic hazard assessment in different regions of the world. In this study, Bayesian approach has been used to obtain estimated seismic parameters. In order to reach this aim, 30 different source regions in Zagros seismotectonic province have been considered. The main assumptions are Poissonian character of the seismic events flow and properties of the Gutenberg- Richter distribution law. The a posteriori probability distribution functions of Mmax (T) and the tail probabilities P(Mmax (T)>M), that will occur in future time intervals of 10, 20, 50, 100 and 475 years are illustrated for source regions. The map of peak ground acceleration (PGA) zonation by probability level of 90% (in g) in rock bed for average return period of 50, 100 and 475 years is presented. According to the results, the maximum acceleration is estimated for the cities of Kermanshah, Ilam, Khorram Abad and Bandar Abbas which are related to NWZ1, NWZ2, NWZ3, NWZ7, NWZ8, SZ3, SH1, PG1 and PG2 sources. Finally, the results of this study are compared with obtained results of non-source approach. [ABSTRACT FROM AUTHOR]

Vulnerability is the variable in which the decision makers can influence, specially when analyzing a geographical space built under obvious seismic hazard conditions. This case of study is centered on the analysis of structural vulnerability in Toluca City, using a qualitative methodology. Three indicators are considered in this article: constructive typologies, age of the constructions and the period of construction based on the application of the General Construction Regulations in Toluca Municipality. The results obtained allowed us to identify four levels of structural vulnerability, in which there can be identified 866 blocks in a very high level of vulnerability and 1430 classified with high vulnerability, where approximately 218 314 people live. The resulting cartography is included in the structural vulnerability reduction plans to manage the disaster risk. At the same time, some lines of inquiry were established for future investigations, mainly when defining the function of vulnerability for the typical buildings in the city, and the analysis of the site effect through the geotechnical conditions of the urban scenery. [ABSTRACT FROM AUTHOR]

The increasing number of damaging earthquakes, induced by underground injection of fluids, demonstrates the need of a structured methodology for critical thinking about and clear communication of induced seismic risk. Using the Pohang, South Korea, geothermal project and the damaging (US$75M) local magnitude ML 5.35 induced earthquake in 2017, we present a straightforward methodology that summarizes induced seismic risk in a single time‐dependent number, the Value at Induced Risk (VaIR). VaIR quantifies the amount of economic losses that will not be exceeded at a given confidence level. Our method reveals that the Pohang project was exposed to a 2% chance of causing economic losses of US$140M or more (1% of US$3.2B or more). The high risk could have been identified during the sequence of reservoir stimulation, lasting almost 2 years. VaIR opens new ways to assess and communicate risk to all stakeholders for informed risk management decision making. Plain Language Summary: High‐pressure injection at a geothermal reservoir close to the city of Pohang, South Korea, triggered a damaging (US$75M) ML 5.35 earthquake in November 2017. We present a straightforward methodology for seismic risk assessment, communication, and management for underground injection of fluids. Our method, Value at Induced Risk (VaIR), combines preoperation loss scenario modeling and magnitude‐frequency statistics of the evolving induced seismicity catalog to monitor the evolution of induced seismic risk in real time. Retrospectively, we apply VaIR to the Pohang case. Operators, regulators, and nonexpert stakeholders could have been well‐informed about the elevating risk caused by underground injection in real time. Application of VaIR to future underground injection projects will help to exclude unacceptable losses with high confidence. Key Points: Value at Induced Risk (VaIR) is a straightforward method to communicate and manage seismic risk caused by underground injection of fluidsVaIR combines preoperation loss scenario modeling and magnitude statistics of the evolving induced seismicity catalog to monitor riskVaIR helps to exclude unacceptable losses with high confidence and to inform operators, regulators and nonexpert stakeholders at risk [ABSTRACT FROM AUTHOR]

The increasing number of damaging earthquakes, induced by underground injection of fluids, demonstrates the need of a structured methodology for critical thinking about and clear communication of induced seismic risk. Using the Pohang, South Korea, geothermal project and the damaging (US$75M) local magnitude ML 5.35 induced earthquake in 2017, we present a straightforward methodology that summarizes induced seismic risk in a single time‐dependent number, the Value at Induced Risk (VaIR). VaIR quantifies the amount of economic losses that will not be exceeded at a given confidence level. Our method reveals that the Pohang project was exposed to a 2% chance of causing economic losses of US$140M or more (1% of US$3.2B or more). The high risk could have been identified during the sequence of reservoir stimulation, lasting almost 2 years. VaIR opens new ways to assess and communicate risk to all stakeholders for informed risk management decision making. Plain Language Summary: High‐pressure injection at a geothermal reservoir close to the city of Pohang, South Korea, triggered a damaging (US$75M) ML 5.35 earthquake in November 2017. We present a straightforward methodology for seismic risk assessment, communication, and management for underground injection of fluids. Our method, Value at Induced Risk (VaIR), combines preoperation loss scenario modeling and magnitude‐frequency statistics of the evolving induced seismicity catalog to monitor the evolution of induced seismic risk in real time. Retrospectively, we apply VaIR to the Pohang case. Operators, regulators, and nonexpert stakeholders could have been well‐informed about the elevating risk caused by underground injection in real time. Application of VaIR to future underground injection projects will help to exclude unacceptable losses with high confidence. Key Points: Value at Induced Risk (VaIR) is a straightforward method to communicate and manage seismic risk caused by underground injection of fluidsVaIR combines preoperation loss scenario modeling and magnitude statistics of the evolving induced seismicity catalog to monitor riskVaIR helps to exclude unacceptable losses with high confidence and to inform operators, regulators and nonexpert stakeholders at risk [ABSTRACT FROM AUTHOR]

The present study area is situated between the latitudes of 21°N and 39°N and the longitudes of 59°E and 77°E. The objective of this study is to estimate seismic hazard in Pakistan as a whole, northern Pakistan and southern Pakistan using cumulative frequency-magnitude distribution and strain energy release methods. The results are in the form of seismicity parameters of a and b-values (zone dependent constants), M1 (the annual mode maxima), M2 (the mean annual rate of energy release), M3 (the maximum credible earthquake), WT (the waiting time for M3 to occur and DT is the delay time. The results indicate that, in general, Pakistan and surrounding region is seismically active (e.g. north Pakistan has b < 1.0). [ABSTRACT FROM AUTHOR]

The degree to which deformation and seismicity is focused on major mapped structures remains a key unknown in assessing seismic hazards and testing continental deformation models. Here we combine 208 Global Positioning System (GPS) velocities with 12‐track Interferometric Synthetic Aperture Radar (InSAR) rate maps to form high‐resolution velocity and strain rate fields for south‐central Tibet. Our results show that deformation is not evenly distributed across the region. We find a few zones with high strain rates, most notably the Yutian‐Zhongba strain rate zone. However, the average of the strain rates is similar within and outside the mapped fault zones. In addition, the slip rates are low on all the conjugate strike‐slip faults widespread in central Tibet. The observations are difficult to reconcile with time‐invariant block models or with continuum models that lack mechanisms for strain localization. Our results support arguments that the most robust estimates of seismic hazard should integrate seismicity catalogues, active fault maps, and geodetic strain rate models. Key Points: Geodetic velocity field shows spatially variable strain within south‐central TibetStrain rates are similar outside and inside the mapped fault zonesConjugate strike‐slip faults in south‐central Tibet have low slip rates (≤4 mm/year) [ABSTRACT FROM AUTHOR]

It is well known that the mechanical and physical properties of subsoil layers as well as poor construction practices play an important role in determining the level of structural damage sustained from earthquakes. Thus, sufficient knowledge of these properties is essential for estimating the weak points of a region. The ground vulnerability index (Kg), an indicator of the weak points of a region, also has a substantial importance role in mitigating earthquake hazards in multidisciplinary studies. In this context, we have used engineering basement shear wave velocity (vs30), fundamental frequencies and peak amplitude values of the horizontal-to-vertical ratio (H/V) to calculate Kg values for the study area (Kocaeli Province, Turkey). Structural damage was investigated after the August 17, 1999 Kocaeli (Mw = 7.4) Earthquake and compared with the calculated Kg values. The results indicate that the Kg values decrease towards the southern part of the study area, which is in good agreement with damage distribution from this earthquake. Kg values of >10 appear to be indicative of the most vulnerable areas in the study area. Structures built along the coastlines in Değirmendere area were the mostly severely damaged or collapsed entirely; we found that the subsoil beneath them have high Kg values of between 10 and 25 In contrast, Kg values in the southern districts, which sustained little or no damage, are relatively low (Kg < 10). In our study, the Kg values and soil types showed good agreement. Potential vulnerable areas also have poor subsoil conditions. Therefore, it could be important to consider these results for the future planning and designing of urban areas. These results could also be used as a rapid way to detect potential vulnerable areas before the occurrence of a destructive earthquake. [ABSTRACT FROM AUTHOR]

During the last years, several crustal seismic sources have been proposed in El Salvador; however, the actual destructive potential of these proposals has not been revealed yet. Here we present several seismic scenarios related with the main crustal faults in the country. We have characterized the corresponding hazard scenarios in a deterministic way, estimating the peak ground accelerations (PGA) including local site effects. In addition, we present a list of 29 sources that can be considered potentially dangerous with their main features when they are available and four seismic scenarios that we consider to be more probable. We have resorted to the February 13th 2001 Mw 6.6 destructive earthquake, the only earthquake occurred in a known crustal source in El Salvador and recorded by the strong motion network, in order to test the methodological approach and the reliability of the PGA results predicted by two available Ground Motion Prediction Equations (GMPEs) including the site effect. The consistence between the values given by the models and the ones recorded during the event provides reliability to our results. This approach allowed us to conclude that faults within the volcanic arc can produce accelerations up to 1 g in the most conservator case (Mw = 7.0), while accelerations up to 0.6 g are usual results related with specific faults within the Salvadoran Volcanic Arc. Besides, the reported damage distribution of the 8th June 1917 earthquakes and its similarity with one of the proposed scenarios allowed us to infer the possible source of this event, the Guaycume Fault. [ABSTRACT FROM AUTHOR]

The 28th September 2018 Sulawesi Supershear earthquake (M W 7.5) was one of the deadliest earthquakes in the recent history of Indonesia causing ∼4000 causalities. The earthquake caused a ∼ 177 km long surface rupture along the Palu-Karo fault. Apart from surface rupture, the earthquake caused extensive earthquake environmental effects (EEEs) around the Palu-Donggala area of Central Sulawesi, Indonesia, which includes tsunami, coastal landslide, liquefaction, ground cracks and more than 7300 landslides in hilly areas. Initial post-event analysis and reports assigned a Modified Mercalli Intensity (MMI) of VII to VIII in Palu City and the surrounding area. Building damage and ground effects caused by the earthquake suggested that seismic intensity was understated. Here we applied the EEEs information from field survey data, published reports, and remote sensing tools to determine macroseismic intensity using the Environmental Seismic Intensity (ESI-07) Scale. The ESI-07 intensity derived from the ground effects suggests the maximum intensity of X-XI, which is 3–4° higher than the traditional intensity estimated by the United States Geological Survey (USGS) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). ShakeMaps were generated considering the ESI-07 values. The ShakeMap was compared with the instrumentally derived ShakeMap for the Palu earthquake, which proves that the ShakeMap prepared from the instrumental data or structural damage data is underrated. We argue that proper documentation of the EEEs is necessary for such damaging earthquakes for future earthquake hazard mapping and planning in the study area and other earthquakes in Indonesia. In addition, this will help in defining the on-fault and off-fault damage zone towards reducing the seismic risk of the Palu Donggala area. • Detailed Earthquake Environmental Effects (EEEs) caused by the 28/09/2018 Sulawesi earthquake (M w 7.5) were collected. • The epicentral ESI-07 intensity as well as the site specific intensity were estimated. • The ESI-07 intensity were compared with Skala Intensitas Gempabhumi (SIG), BMKG. • ESI-07 ShakeMap were generated using the Surface Rupture data and ESI-07 values. • The maps can be used to guide efficient and strategic seismic hazard assessment and land use planning. [ABSTRACT FROM AUTHOR]

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between highpressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values < 1 and many post-shut-in earthquakes, versus (ii) shallower earthquakes in Paleozoic rocks ∼400 m below HF, with smaller magnitudes (M < 1), b-values > 1.5 and few post-shut-in earthquakes. Based on geologic history, laboratory experiments and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ∼1 km and argues for poroelastic stress transfer also having a primary influence on seismicity. [ABSTRACT FROM AUTHOR]

The empirical factor Kappa (κ), governs the rapid decay of spectral amplitude at high frequencies. It is one of the important parameters required in the simulations of earthquake strong ground motions. The present study estimates κ for 16 sites of Kachchh region of Gujarat (India). The Kachchh region is one of the most seismically active intraplate regions of the world that has experienced shocks of magnitude up to 8.0 in past. We have analyzed 159 accelerograms of 34 earthquakes of magnitude range 3.3-4.9 to estimate the κ. The estimated values of κ vary from 0.016 to 0.045 with an average of 0.023. Our results show no significant dependence of κ on distance (R) for the region. The analysis based on two sites shows that κ0 (κ at R = 0) is lower for the hard rock site (0.016) as compared with the value for the soft rock site (0.0201). One of the important observations of this study is that κ is not the source property for Kachchh region. The estimated values of the κ are useful for the stochastic simulation of earthquake strong ground motions. [ABSTRACT FROM AUTHOR]

In the Central Andean region of Argentina, we found gravimetric and geomorphological evidence of an uplifting of the crystalline basement of Pie de Palo range. Within this zone, we observed a positive gravimetric anomaly in the extreme South of Pie de Palo, extending towards the South of Pampean ranges. By means of the geophysical technics, it was possible to determine the magnitude and geometrical form of the anomalous body. The evidence of a tectonic uplifting is also clearly manifested in the LandSat images, by observing the displacement of the course of the San Juan River towards the South. The study region is one of the major cortical and lithospheric regions with seismic activity in the country, where three of the most devastating earthquakes occurred over the last 73 years. The results would indicate that this region will continue to be one of the major seismically generating potential, significantly implying seismic dangers. The seismic risk studies indicate that the greatest hazard zone is found between the Pre-Cordillera and the Pie de Palo Range. The highest maximum acceleration values (PGA) are 242, 393, and 543 gal for return periods of 72, 475, and 2475 years, respectively. [ABSTRACT FROM AUTHOR]

After the Tohoku earthquake in 2011, we observed that aftershocks tended to occur in a wide region after such a large earthquake. These aftershocks resulted in secondary damage or delayed rescue and recovery activities. In addition, it has been reported that there are regions where the intensity of the vibrations owing to the aftershocks was much stronger than those associated with the main shock. Therefore, it is necessary to consider the seismic risk associated with aftershocks. We used the data regarding aftershocks that was obtained from the Tohoku earthquake and various other historically large earthquakes. We investigated the spatial and temporal distribution of the aftershocks using the Gutenberg-Richter law and the modified Omori law. Subsequently, we previously proposed a probabilistic aftershock occurrence model that is expected to be useful to develop plans for recovery activities after future large earthquakes. In this study, the probabilistic aftershock hazard analysis is used to create aftershock hazard maps. We propose a hazard map focusing on the probability of aftershocks on the scale of the main shock for use with a recovery activity plan. Following the lessons learned from the 2011 Tohoku earthquake, we focus on the simultaneous occurrence of tsunamis and aftershocks just after a great subduction earthquake. The probabilistic aftershock hazard analysis is used to derive load combination equations of the load and resistance factor design. This design is intended to simultaneously consider tsunamis and aftershocks for tsunami-resistant designs of tsunami evacuation buildings. [ABSTRACT FROM AUTHOR]

On 6 February 2016 (UTC 19:57), the Meinong earthquake with Richter magnitude (ML) 6.6 struck southern Taiwan and caused hundreds of damaged buildings, resulting in 117 casualties. We investigated the relationship between the damaged buildings and the ground motion in the forms of peak ground acceleration (PGA), peak ground velocity (PGV), pseudo-spectral acceleration (SA) at 0.3 s (SA0.3), 1.0 s (SA1.0), and shaking duration to identify which ground motion parameter most represents building damage. PGV and SA1.0 present better correlation with consequent damage. The Intensity converted from PGV presents better correlation to the damage than PGA. We disaggregated the TEM PSHA2015 hazard contribution to the Meinong earthquake damage region (Southern Taiwan) from different seismic source typologies to clarify the seismic source contributing to the hazard. The hazards contributed by the Meinong earthquake were 16, 26, and 23% for PGA, SA0.3, and SA1.0, respectively. The predicted seismic hazard source areas were 38, 61, and 75% for PGA, SA0.3, and SA1.0, respectively, for the PSHA with a return period of 475 years. This result indicates that the 2016 Meinong earthquake did partially diminish the seismic hazard potential in southern Taiwan. However, more than about 80% of the seismic hazard potential, especially the fault sources were not yet released. These values suggest that the seismic hazard potential in southern Taiwan remains high regardless of the 2016 Meinong earthquake. [ABSTRACT FROM AUTHOR]

Large-magnitude mining-induced seismic events can occur as a result of local rock mass stress increase. High apparent stress events can be used as a proxy to identify increases in local rock mass stress conditions. This paper proposes a relative apparent stress ratio (ASR) for quantifying apparent stress of a seismic population. Variations in ASR are analysed over time with reference to seismic hazard inferred from the magnitude of seismic events. The proposed ratio is examined through examples of seismic populations from a single deep Canadian mine. [ABSTRACT FROM AUTHOR]

The source of the 1886 Charleston, South Carolina earthquake influences the computed seismic hazard of the Southeastern U.S. and thus impacts public policy and engineering practice. However, because the 1886 rupture predated seismic instruments, its source is highly uncertain. This study presents probabilistic seismic-source inversions of the Charleston earthquake from liquefaction evidence and historical intensity reports. Using the latest predictive models and a novel inversion approach, we seek to constrain the magnitude, location, and orientation of the 1886 rupture. Probability distributions of rupture magnitude are conditioned on both the "Woodstock Fault" – a commonly inferred source of the 1886 event – and on an unknown source, wherein the uncertainties of fault location and orientation are considered. These distributions are compared to the M w 6.7-M w 7.5 distribution adopted by the U.S. National Seismic Hazard Model Project (NSHMP). Collectively, the results do not provide strong support for the hypothesized Woodstock Fault. This is not to say the Woodstock Fault does not exist or could not have caused the 1886 rupture, but rather, that the position of the 1886 source model cannot be constrained by the data and models studied herein, given the large uncertainties inherent to each. While this is at odds with the underlying assumption of prior studies, the results nonetheless generally uphold the magnitude distribution adopted by the NSHMP. The largest uncertainties inherent to this distribution are identified and could be diminished in the future. Finally, we note that the inversion methodology used here is not specific to any region, or to certain types of evidence, but can be applied to any seismic zone and to any co-seismic response. This methodology allows for uncertainty to be accounted for in a more complete and transparent manner when inverting seismic source parameters from macroseismic data. Of course, any limitations, biases, or unmodeled uncertainties inherent to these data must be understood, and their implications acknowledged, as further discussed herein. • The source of the 1886 Charleston earthquake influences the computed seismic hazard of the region but is highly uncertain. • The earthquake's source is probabilistically inverted from liquefaction evidence and felt intensity reports. • The results do not provide strong support for the Woodstock Fault – an often inferred source – which is not to say it does not exist. • While this is at odds with the assumption of many prior studies, the results generally support the magnitude distribution adopted by the National Seismic Hazard Modeling Project. • Our approach allows for more complete accounting of uncertainties when inverting seismic sources from macroseismic data. [ABSTRACT FROM AUTHOR]

Seismic hazard assessment is carried out by utilizing deterministic approach to evaluate the maximum expected earthquake ground motions along the Western Coastal Province of Saudi Arabia. The analysis is accomplished by incorporating seismotectonic source model, determination of earthquake magnitude ( M ), set of appropriate ground motion predictive equations (GMPE), and logic tree sequence. The logic tree sequence is built up to assign weight to ground motion scaling relationships. Contour maps of ground acceleration are generated at different spectral periods. These maps show that the largest ground motion values are emerged in northern and southern regions of the western coastal province in Saudi Arabia in comparison with the central region. [ABSTRACT FROM AUTHOR]

This paper presents a probabilistic approach for seismic stability analysis of a slope at a given site in a specified exposure time. For a probabilistic seismic stability analysis, the ground motion parameter, in terms of the peak ground acceleration (PGA), at a given site in a specified exposure time of interest (say, 30 years) is treated as a random variable, and the PGA distribution at the given site is derived based on the USGS National Seismic Hazard Maps data. Further, the spatial variability of the soil property is simulated herein by a random field, and the fluctuation of the groundwater level is simulated by a random variable. Within the probabilistic framework, a deterministic model for evaluating the slope stability is required; here, a pseudo-static analysis is adopted and implemented through 2D finite difference program FLAC version 7.0. In the face of the uncertainties in the input parameters, the performance or safety of the slope is expressed as a failure probability; within the proposed probabilistic analysis framework, a recently developed sampling method is adopted for the uncertainties propagation through the deterministic solution model. This probabilistic analysis framework is demonstrated with an illustrative example of a two-layer earth slope. Finally, a parametric study is undertaken to investigate how the failure probability of the slope (at a given site in a specified exposure time) is affected by the uncertain factors such as the earthquake-induced ground motion and the spatial variability of soil property. The study results demonstrate the versatility and effectiveness of the proposed framework for probabilistic seismic stability analysis of slope at a given site in a specified exposure time. [ABSTRACT FROM AUTHOR]

A scoured-bridge system has the potential to be subject to earthquake loads. In a bridge’s service life, the depth of the scour hole may gradually increase with time due to future flood events. So, scour is a time-dependent hazard. Few efforts have been made to investigate the time-dependent scour hazard on bridge systems under seismic loads. In this work, time-dependent seismic fragility analysis is adopted to study scoured-bridge systems under earthquake loads across a bridge’s whole service life. Through time-dependent fragility analysis, the annual fragility curves for different damage states of the bridge systems under combined hazards can be obtained efficiently, in which the uncertainty of materials, scour depth, and ground motions are considered with the Latin Hypercube Sampling method. Also, the fragility surfaces for different damage states can be obtained, which is conditional on both bridge service time and seismic intensity. By combining the fragility surface with earthquake hazards at a given site, the annual seismic risk or cost of scoured-bridge systems can be calculated. Two bridge models are used for the time-dependent fragility analysis. The results show that the probability of all the damage states increases with both time and seismic intensity; however, it does not increase linearly with time and seismic intensity. The nonlinearity depends on the severity of damage state. The damage probability is affected much less by time and seismic intensity if they are below certain thresholds. Then it quickly increases with both time and seismic intensity before another threshold is reached. The thresholds for both stages of time and seismic intensity become bigger when the severity of the damage state changes from slight damage to collapse. [ABSTRACT FROM AUTHOR]

Seismic site amplification and seismic hazard maps are crucial inputs for decision making and risk evaluation in places where seismicity imposes a significant risk to human life and infrastructure. In this work, we propose a novel machine learning (ML) based methodology to integrate qualitative and quantitative data to map the degree of seismic amplification in an area of Chile, one of the most seismically active countries on Earth. Our method uses measurements of surface shear wave velocities (V s30) and predominant frequencies (f 0) combined with gravity anomaly maps to update the geographic extension of seismic amplification classes. Additionally, we trained the predictive models to interpolate and extrapolate V s30 and f 0 to the unsampled sites. Applying this method to the Santiago basin resulted in (i) a refined seismic amplification map, and (ii) maps of V s30 and f 0 estimated with improved accuracy. The best predictions, obtained by ML techniques and validated through cross-validation, are possibly due to the inclusion of spatial covariates for algorithm training, enhancing the ability of the model to capture the spatial correlations of geological, geophysical and geotechnical data. The estimation of predominant frequencies (f 0) is improved considerably by including gravity as a covariant. The accuracy of the f 0 predictions apparently depends more on the choice of covariates than on the algorithm used, while the V s30 predictions are more sensitive to the chosen algorithm. These results illustrate the great potential of machine learning predictive algorithms in digital soil mapping, which surpass traditional geostatistical techniques. The major contribution of this work is to introduce a novel methodology, based on artificial intelligence models, to extend local measurements of site-specific dynamic properties. This information can be used to quantitatively estimate seismic hazard over a regional scale. • We propose a methodology for integrating data to map dynamic site characterization using machine learning. • Our method uses measurements of Vs30 and f0 combined with gravity anomaly and geology. • We trained predictive models to interpolate Vs30 and f0 in the Santiago de Chile basin. • The best predictions were obtained thanks the inclusion of spatial covariates for algorithm training. • The estimation of f0 is considerably improved by including gravity as a covariant. [ABSTRACT FROM AUTHOR]

The Sichuan-Tibet Railway in eastern Tibet runs across numerous seismogenic faults with high seismic risks. The Lancangjiang fault (LCJF), one of the essential strike-slip faults within the Qiangtang block, traverses the railway. However, the geometry and late Quaternary activities of the LCJF remain unclear, limiting the assessment of seismic hazards on the Sichuan-Tibet Railway and the understanding of kinematic patterns in eastern Tibet. Based on the interpretation of high-resolution satellite imagery, field observations, and shallow geophysical exploration, we first mapped the detailed geometry of the northern LCJF. It consists of two branches: Yangda-Yaxu fault (YYF) and Baqing-Leiwuqi fault (BLF), which merge eastwards onto the main LCJF. Displaced landforms and multiple numerical dating techniques reveal that the YYF is a mainly sinistral fault with a late Quaternary slip rate of ~2.2 + 0.6/−0.5 mm/yr and a minor vertical component (~0.1 mm/yr). The BLF undergoes an oblique motion with a left-lateral slip rate of ~1.2 + 0.5/−0.3 mm/yr and a northeast-vergent reverse rate of ~1.2 + 0.4/−0.2 mm/yr in the Holocene. Vector analysis of slip rates suggests that the LCJF has a sinistral rate of ~3.5 + 1.1/−0.8 mm/yr with a reverse component of ~1.6 + 0.4/−0.3 mm/yr, displaying an essential role in strain partitioning of eastern Tibet. Together with slip rates of other intra-block faults, the kinematic pattern of eastern Tibet probably applies to the sub-block model. Offset geologic units yield a total displacement of ~10–11 km for the YYF. Using the slip rate of the YYF, the LCJF was initiated at ~5.9–3.9 Ma, probably related to the establishment of the present-day strain pattern and the onset of crustal thickening in eastern Tibet during the late Miocene. In addition, the active YYF and BLF across the Sichuan-Tibet Railway have a seismic potential of Mw ~7.2–7.3 that will produce a ~ 1.8–2.0 m sinistral slip on the YYF, and a ~ 2.0 m horizontal, and ~ 1.1–1.3 m reverse motion on the BLF. They will pose a high seismic hazard potential on the railway. This study provides quantitative data for regional seismic hazard analysis and shows insights into the deformation mechanism of the plateau. • The geometry of the northern LCJF is first mapped. • The northern LCJF has a late Quaternary ~3.5 mm/yr sinistral and ~ 1.6 mm/yr reverse rate. • The seismic potential of the northern LCJF on the Sichuan-Tibet Railway is estimated. • The LCJF takes an important role in strain partitioning in eastern Tibet. • The initiation of the LCJF is related to the late-Miocene tectonic event in eastern Tibet. [ABSTRACT FROM AUTHOR]

Seismic Hazard assessment is essential component for seismic risk analysis, mitigation and emergency management. Researches assessed hazard in the selected parts of Pakistan including Baluchistan province. Seismic Hazard Assessment for Khyber Pukthunkhwa (KPK) province has been previously done on large scale, however no such work has been carried out for Baluchistan province. The seismicity and frequency major earthquakes in Baluchistan province, require detailed Seismic Hazard Assessment. This paper presents the Probabilistic Seismic Hazard Assessment (PSHA) of Baluchistan Pakistan, emphasizing on spectral acceleration parameters. Earthquake loading is defined in terms of 0.2sec and 1.0sec spectral acceleration. Seismic hazard is estimated in terms of Peak Ground Acceleration (PGA) using Earthquake Risk Assessment (ERA) framework. This Framework is developed using Ambarasey's 2005 Ground Motion Prediction Equation for the assessment of hazard. A maximum Peak Ground Acceleration of 1.21 g, occurs in the district of Sibi, while minimum was found in Chaman of 0.03g using 1.0sec (S1) spectral acceleration and 0.65g at Quetta using 0.2sec (Ss) spectral acceleration. Seismic hazard mitigation strategies are recommended depending on the results. [ABSTRACT FROM AUTHOR]

The Taiwan Earthquake Model (TEM) was established to assess the seismic hazard and risk for Taiwan by considering the social and economic impacts of various components from geology, seismology, and engineering. This paper gives the first version of TEM probabilistic seismic hazard analysis for Taiwan in these aspects. We named it TEM PSHA2015. The model adopts the source parameters of 38 seismogenic structures identified by TEM geologists. In addition to specific fault source-based categorization, seismic activities are categorized as shallow, subduction intraplate, and subduction interplate events. To evaluate the potential ground-shaking resulting from each seismic source, the corresponding ground-motion prediction equations for crustal and subduction earthquakes are adopted. The highest hazard probability is evaluated to be in Southwestern Taiwan and the Longitudinal Valley of Eastern Taiwan. Among the special municipalities in the highly populated Western Taiwan region, Taichung, Tainan, and New Taipei City are evaluated to have the highest hazard. Tainan has the highest seismic hazard for peak ground acceleration in the model based on TEM fault parameters. In terms of pseudo-spectral acceleration, Tainan has higher hazard over short spectral periods, whereas Taichung has higher hazard over long spectral periods. The analysis indicates the importance of earthquake-resistant designs for low-rise buildings in Tainan and high-rise buildings in Taichung. [ABSTRACT FROM AUTHOR]

We present a new seismic source zone model for the seismic hazard assessment of Slovakia based on a new seismotectonic model of the territory of Slovakia and adjacent areas. The seismotectonic model has been developed using a new Slovak earthquake catalogue (SLOVEC 2011), successive division of the large-scale geological structures into tectonic regions, seismogeological domains and seismogenic structures. The main criteria for definitions of regions, domains and structures are the age of the last tectonic consolidation of geological structures, thickness of lithosphere, thickness of crust, geothermal conditions, current tectonic regime and seismic activity. The seismic source zones are presented on a 1:1,000,000 scale map. [ABSTRACT FROM AUTHOR]

In this study, Interferometric Synthetic Aperture Radar (InSAR) was used to determine the seismogenic fault and slip distribution of the 3 July 2015 Pishan earthquake in the Tarim Basin, western China. We obtained a coseismic deformation map from the ascending and descending Sentinel-1A satellite Terrain Observation with Progressive Scans (TOPS) mode and the ascending Advanced Land Observation Satellite-2 (ALOS-2) satellite Fine mode InSAR data. The maximum ground uplift and subsidence were approximately 13.6 cm and 3.2 cm, respectively. Our InSAR observations associated with focal mechanics indicate that the source fault dips to southwest (SW). Further nonlinear inversions show that the dip angle of the seimogenic fault is approximate 24°, with a strike of 114°, which is similar with the strike of the southeastern Pishan fault. However, this fault segment responsible for the Pishan event has not been mapped before. Our finite fault model reveals that the peak slip of 0.89 m occurred at a depth of 11.6 km, with substantial slip at a depth of 9-14 km and a near-uniform slip of 0.2 m at a depth of 0-7 km. The estimated moment magnitude was approximately Mw 6.5, consistent with seismological results. [ABSTRACT FROM AUTHOR]

The probabilistic seismic hazard curves were based on appropriate attenuation relationships at rock sites with a probability of exceedance of 10% in 50 years in this study. Results from the model were compared to the response spectra proposed in Section 7 of TEC '07 and were found to differ in both amplitude and frequency content. The impact of these differences has been investigated with respect to building performance evaluation. Specifically, modal capacity diagrams and response spectra have been obtained for five buildings. Based on the diagrams and spectra, peak displacements have been calculated as well, revealing significant differences in the demand displacement curves of the buildings. As a result, damage estimates and predicted building performance will deviate from site specific performance to a greater degree. Using site-specific spectra and field data will be important for future earthquake-resistant design. One of the conclusions of the study is that the Code spectra do not offer a sufficient or comprehensive enough set of seismic demands and would lead to an under estimation of seismic hazard in the region of study. Therefore, site-specific design spectra for the region should be developed which reflect the characteristics of local sites. [ABSTRACT FROM AUTHOR]

The uncertainty assessment for the development of the new seismic hazard maps of Spain is explained in this work. A detailed description of how uncertainties are considered in the different phases followed for the probabilistic seismic hazard assessment study is presented. Special emphasis is given to the characterization of the uncertainty of earthquake size parameters contained in the catalog, and their propagation to subsequent phases of the analysis such as catalog homogenization, completeness and declustering. Aleatory and epistemic uncertainties are examined and assessed using Monte Carlo simulations and a logic tree, respectively. The final impact of uncertainty in hazard estimates is evaluated through coefficient of variation maps, showing the areas where larger and lower variability is obtained. The hazard maps developed in this work are intended to be the basis for the future revision of the Spanish seismic code. [ABSTRACT FROM AUTHOR]

In the present study, the strong motion data of the 4 April 2011 western Nepal earthquake (M 5.7) recorded by a dense network of 24 strong motion accelerograph stations have been used to estimate horizontal and vertical component of the peak ground acceleration (PGA) to better understand its bearing on the seismic hazard scenario of the Central Himalayan region. We assimilated attenuation curves using the observed PGA values and found that the zone is associated with higher H/V ratio in which the attenuation trend remains bimodal with one trend for closer distance up to 100-120 km, while the other trend corresponds to distances extending beyond 1000 km. We infer that the two different PGA trends have close bearing on the major tectonics and structural set-up of the region, which is possibly attributed to subsurface structural variation through which the seismic wave travels, suggesting changes of crustal heterogeneities beneath the source zone. The present work may improve the concept of ground motion model for evaluating seismic hazard for the Himalaya. [ABSTRACT FROM AUTHOR]

The last version of the National Building Code of Canada was issued in 2010. The next version will be issued in 2015. In the code cycle between 2010 and 2015 significant changes have taken place in the seismic design provision. The main factor that drives these changes is an improved understanding of the seismic hazard across the country. Changes have also been introduced in the site effect factors. The structural design provisions have been appropriately adjusted to respond to changes in the estimates of hazard and the new site effect factors. There are also new provisions related to design in regions of low hazard, buildings with flexible diaphragms, buildings with inclined columns, passive energy dissipation systems, base isolation, rocking foundations, glazing systems, racks, and elevators. Some of the changes are briefly discussed. The main focus of the paper is, however, on the revisions to the structural design provisions. [ABSTRACT FROM AUTHOR]

In this study, stochastic and probabilistic seismic hazard procedures are used to estimate the seismic hazard for wind turbine tower sites in Zafarana Wind Farm, Gulf of Suez, Egypt. The seismic activity in and around the study area, which includes many active fault systems along the Gulf of Suez resulting in many moderate and strong earthquakes, has been well described. These earthquakes result in major stress drops in the Eastern desert and Gulf of Suez area. These recent findings have helped to reshape the seismotectonic environment of the Gulf of Suez area, which is a perplexing tectonic domain. Based on the new information and data collected, the seismic hazard for the Gulf of Suez region, particularly the wind turbine towers in Zafarana Wind Farm and its vicinity, was reexamined using probabilistic and stochastic approaches. Alternate seismic source and magnitude-frequency relations combined with various indigenous and 'foreign' attenuation relationships were adopted within a logic tree formulation to quantify and project the regional exposure on a set of hazard maps. The hazard maps showed the peak horizontal ground acceleration and spectral acceleration at PGA, 0.1, 2.0 and 4.0 s. These acceleration levels were computed for 20 and 10 % probabilities of being exceeded in 50 years. Finally, the 0.5, 1, 5, 10 and 20 % damping median response spectra are provided for wind turbine towers in Zafarana Wind Farm site based upon a stochastic simulation technique and on borrowed attenuation relationships. [ABSTRACT FROM AUTHOR]

This paper examines the performances of lightly- and heavily-damped rolling isolation systems (RISs) located within earthquake-excited structures. Six steel structures of varying height and stiffness are selected so as to represent a range of potential RIS installations. Computation models of representative frames from each of the six structures are reduced through dynamic condensation and assembled with models for biaxial isotropic hysteretic behavior within each floor. A novel reduced order modeling approach is presented in this paper. The method combines a dynamic condensation of a linear-elastic frame with the inelastic-push over curve for a detailed elastic–plastic frame model and a novel bi-axial hysteretic model for the net inter-story inelastic behavior. The reduced inelastic model combines stiffness and mass matrices from the reduced linear model with the bi-axial inelastic floor model, and is subsequently fit to push-over curves from the detailed hysteretic model. The resulting reduced order model has three coordinates per floor and provides a much simpler model for simulating the floor responses of inelastic structures. The resulting inelastic structural models are isotropic in plan and uniform along the height. Suites of recorded ground motions representative of near-fault and far-field hazards are scaled and inputted into these hysteretic reduced models. The bidirectional floor responses at varying heights are then applied to experimentally-validated models of lightly- and heavily-damped RISs. Empirical cumulative distribution functions of peak isolator responses (relative displacement and total acceleration) for the two systems are compared, from which installation guidelines are presented. [ABSTRACT FROM AUTHOR]

The relation between applied stress and wave velocity is examined firstly at the laboratory-scale by using ultrasonic technique. Subsequently, an island longwall face under hard-thick strata, suffering from the threat of seismic hazards, e.g. rock burst, strong tremor, was chosen for a case study of passive velocity tomography. Based on continuous seismic monitoring during mining operation, passive tomographic imaging has been used to locate high seismic activity zones and assess seismic hazard around the face. The results show that the high velocity and velocity gradient regions correlated well with the high seismic activities occurred in future mining period. In addition, the high velocity or velocity gradient regions redistributed with the retreat of coalface and large-scale movement of key strata. Passive velocity tomography can be a promising tool to continuously monitor the relatively high stress zone or evaluate seismic hazard in underground coal mining. [ABSTRACT FROM AUTHOR]