Sudden Earthquake Research Articles

A rapid and automated analysis procedure for seismic response of arch dams

The seismic safety of arch dams has long been a focal point of research. Due to the complexity of modeling and computation, analyzing the seismic response of arch dams using traditional finite element methods requires a considerable amount of time. In the event of a sudden earthquake, it is challenging to quickly obtain stress analysis results or conduct a safety assessment. To address these issues, a rapid and automated analysis procedure is proposed in this paper, providing seismic response of arch dams within hours after an earthquake. The procedure includes a pre-processing program, a computing program EACD-3D-2008, and a post-processing program, achieving a fully automated process from generating non-uniform earthquakes to analyzing dam dynamic responses and visualizing computation results. As a case study, the 294.5 m high Xiaowan arch dam in southwest China is analyzed, which is equipped with strong motion instruments that have recorded several small earthquakes. The case study revealed that accounting for the non-uniformity of the earthquake significantly improves simulation results, with maximum principal stresses typically occurring near the dam-foundation rock interface. Additionally, the procedure effectively compensates for missing data, allowing for the successful supplementation of the missing acceleration records. For stronger earthquakes, high-stress regions are clearly displayed in the result visualization, providing an effective reference for safety assessment. The case study validated the accuracy and wide applicability of the procedure, demonstrating its potential to offer valuable insights for similar analyses in various engineering projects.

Quasi-distributed optical fiber sensing for the coupled vibration analysis of high-speed train-bridge coupled system under earthquakes

Due to the extensive construction of high-speed rail lines passing through seismically active areas, the possibility of a sudden earthquake occurring during train operation is very high. Additionally, the earthquake will intensify the dynamic response of trains and bridges, causing serious bridge damage. In this work, the dynamic response behavior of the bridge structures in the coupled train-bridge system under the earthquake is investigated based on the 4-table shaking table system. Shaking table experiments are also conducted on a high-speed railroad model of simple-supported girder bridge at a scale of 1/10 with the simulated layers of China Railway Track System type II (CRTS II) ballastless track slabs. The strain responses of various components, including rails, track plates, base plates, and beams, were measured on the bridge using quasi-distributed fiber optic gratings, both with and without seismic actions. Additionally, the seismic isolation characteristics of the fasteners and the CA mortar layer were investigated. The dynamic performance of the coupled train-bridge system under earthquakes was studied in both the time and frequency domains.

IMPACT OF HIGH RADIO FREQUENCY SATELLITE OSCILLATIONS ON INITIATING EARTHQUAKES

Advanced satellite technology is worse than all the disasters on Earth due to the lack of dynamic security. The study of earthquakes is the most innovative research of all man-made disasters - no doubt, but there are new horizons of wonder for the thoughtful. Earthquakes are increasing unexpectedly in different countries of the world. People of most countries are worried about sudden earthquakes, but no one is able to reveal the main secret of these earthquakes. Many are blaming nature for this earthquake. Through this survey the exact origin of the matter has been presented to the whole world with proper evidence. Research shows that climate criminals are misusing advanced satellite technology to cause these earthquakes. According to research, misuse of advanced satellite technology causes artificial earthquakes at specific GPS locations on Earth, resulting in severe damage to humans, animals, plants and other objects. The intensity of these earthquakes is so intense that everyone is surprised. Studies have shown that the misuse of satellite technology has caused massive damage in man-made technological earthquake at a particular tectonic plate and other disasters. Due to these sudden earthquake, human suffering increases, standing institutions are demolished, road communication systems are ruptured, crop lands and residential areas are destroyed, individuals lose their lives. The study revealed that artificial earthquakes are caused by sudden radio-waves and strong oscillations of variable magnitude anywhere on earth. The study also showed the climate criminals use various fake messages and wireless tracking to influence policy-makers, the public and the media, as can be doubted in this study, All citizens and administrations should be aware and vigilant to prevent the rise of earthquake terror. The research shows that using advanced satellite technology, earthquakes can be created in time on any tectonic plate on the Earth. Moreover, the question remains that when technology was not invented, but earthquakes occurred - which were natural. Humans now generate artificial oscillations at specific GPS locations through earthquake simulation coding by multiplying the magnetosphere of previous natural earthquakes. The study shows that the EMMAST (Earthquake Mitigation and Management through Advanced Satellite Technology) model will make disaster mitigation systems safer and more efficient, saving millions of lives. The study on earthquakes is unique with world- class scientific research, which will open many research gateways for future generations.

Sustainability and resilience of steel – shape memory alloy reinforced concrete bridge under compound earthquakes and functional deterioration within entire life-cycle

Bridges may suffer damage and failure from sudden earthquakes and continuous functional deterioration within their lifetime, resulting in severe consequences to both economy and society. The shape memory alloy (SMA) is a promising material with self-centering and corrosion-resistant characteristics. This study considers the steel-SMA reinforced concrete bridge as a potential alternative to mitigate the consequences induced by earthquakes and functional deterioration within its service life. Achieving carbon neutrality is an urgent goal due to the issues related to global warming, so herein the sustainability is necessarily assessed in terms of environmental, social, and economic metrics. Besides, structures are expected to recover their functionality after hazards efficiently. Thus, resilience describing the recovery ability of the structures needs to be assessed. A novel framework of life-cycle sustainability and resilience assessment is proposed and applied to assess the steel-SMA reinforced concrete bridge considering the stochastic process of earthquakes and functional deterioration, and the results are compared with those of the conventional bridge. The comparison results confirm that the steel-SMA reinforced concrete bridge is more sustainable and resilient under earthquakes and functional deterioration in a long-term perspective under the investigated scenarios. Specifically, it can contribute the carbon neutrality by reducing the long-term carbon dioxide emissions from transportation infrastructures.

Architectural characteristics and determination of load-bearing capacity as a key indicator for a strengthening of the primary school buildings: Case study Osijek

Safety is one of the most important characteristics of a school building. The major role of school space in the children’s growth encouraged architects, engineers, and scientists to analyze existing school buildings construction systems and possibilities for their strengthening. The estimation of earthquake structural damage is a very useful tool in reducing the impact of earthquake effects on material and social elements. This is extremely important for schools so that those with insufficient seismic resistance can be strengthened and thus prevent collapse in the event of a sudden earthquake. In this paper, the architectural and structural characteristics of the existing primary school buildings in Osijek (Croatia) will be analyzed in order to perform an estimation of earthquake structural damage on the example of a selected school building reinforced concrete (RC) frame. A detailed description of primary school buildings development shows that RC frame was the most common type of school building construction system in the city of Osijek. The review and analysis of each building can become a study or manual for a quality renovation. The approach to their renovation, extension, and reconstruction must be well studied, scientifically based, and have clear goals that will satisfy all users of the school building.

Rapid assessment of seismic intensity based on Sina Weibo — A case study of the changning earthquake in Sichuan Province, China

Disaster information acquisition and assessment in China primarily depends on disaster-related governmental departments at all levels. As new challenges faced by disaster emergency management arise, a gap still exists in the timeliness and completeness of rapid disaster assessment. The development and popularity of social media has opened up new channels. Social media data, containing massive amounts of disaster information, has the advantages of timeliness, efficiency, and multiple spatiotemporal scales and can supplement existing methods. Based on the dominant social media platform in China, Sina Weibo, this paper proposes a method of extracting intensity information from Weibo texts, including social perceptions such as shaking, emergency reaction, mood and visible damage, which can support the rapid assessment of seismic intensity. By taking the Changning earthquake in Sichuan Province, China, as a case study, we verify the feasibility of hazard information extraction from Weibo. The results show that the intensity information derived from Weibo in the short-term can respond to a sudden earthquake promptly, then effectively identify the main earthquake affected area, locate the possible orientation close to the meizoseismal area and depict the situation in 10 min. We also propose a grid-based correction method, which synthesizes the hotness-intensity matrix and a seismic attenuation-based model. Compared with taking the seismic attenuation model directly, the proposed correction method improves the accuracy of correct recognition rate of seismic intensity assessment to 82% on average and reduces the false recognition rate significantly. The proposed framework of rapid assessment and correction reveals that the combination of social perception and hazard intensity plays a valuable and promising role as a supplement of traditional disaster assessment approach.

A STUDY ON RECENT EARTHQUAKES IN AND AROUND BANGLADESH

Bangladesh is a South Asian country with a dense population situated in a very vulnerable position of earthquake faults where sudden earthquakes can cause a great loss of lives and properties. This paper deals with the magnitude and focal depth of earthquakes that have been felt from 2015 to 2019 having Richter magnitude more than 3. Maximum earthquakes with a magnitude of 3.0 to 4.9 have occurred at the northern side of Bangladesh whereas at the eastern side the values are between 4.0 to 5.9. It was seen that considerable earthquakes occurred in 2019 at the northern side of Bangladesh that indicates a major earthquake may happen in this area from the stored energy and can cause a devastating effect. It has been observed that Earthquake with more than 3 Richter magnitudes has happened in all five years in February, April, August, and September where January and December have comparatively fewer earthquake records. Focal depths have been found to be higher in 2016 related to other years. A correlation equation has been developed between magnitude and focal depth.

Optimum life-cycle maintenance strategies of deteriorating highway bridges subject to seismic hazard by a hybrid Markov decision process model

Highway bridges are a class of important infrastructure components in transportation networks. Highway bridges will inevitably deteriorate over time due to various external impacts, such as traffic loads and corrosion. In seismic-prone areas, seismic hazard is another critical factor that threatens the normal operation of ageing highway bridges. To ensure adequate safety of ageing highway bridges under potential earthquake shocks, it is imperative to perform proper maintenances during their service life. This paper aims at optimizing the life-cycle maintenance strategies for highway bridges under the combinatorial threats of progressive deterioration and sudden earthquakes. Driven by the distinct characteristics of the two threats, we have proposed a novel hybrid Markov decision process model that integrates a discrete-time Markov decision process model for dealing with progressive deterioration and a continuous-time Markov decision process model for dealing with sudden earthquakes into a unified framework. The proposed model is further reduced into the form of a discrete-time Markov decision process model with an equivalent state transition matrix and an equivalent discount factor, which can be easily solved by dynamic programming. A ternary state space that collectively describes corrosion initiation, corrosion damage cumulation, and seismic damage cumulation is defined. A gamma process and a Poisson process are adopted to model bridge corrosion and earthquake occurrences, respectively. To demonstrate the application of the proposed framework, a numerical example is conducted, in which the optimizations with respect to the maintenance strategy, inspection interval, and design performance level of a hypothetical highway bridge are carried out successively.

Sloshing Motion in a Real-Scale Water Storage Tank under Nonlinear Ground Motion

Water storage tanks in cities are usually large and are occasionally affected by earthquakes. A sudden earthquake can cause pressure pulses that damage water containers severely. In this study, the sloshing motion in a high filling level tank caused by seismic excitation is investigated by the numerical method in a 2D model. Two well-studied strong earthquakes are used to analyze the broadband frequency nonlinear displacement of the tank both in the longitudinal and vertical directions. Based on careful experimental verification, the free surface motion and the elevations at the side wall are captured, and the sloshing pressure response is examined. The results show that the 2D section of the cylindrical tank can be used to estimate the maximum response of the 3D sloshing, and the water motions under the seismic excitations are consistent with the modal characteristics of the sloshing. The time histories response of the water motion reflected that the sloshing response is hysteretic compared with the seismic excitation. The anti-seismic ability of the damping baffle shows that its effect on sloshing pressure suppression is limited, and further study on the seismic design of water tanks in earthquake-prone regions is needed.

Seismic performance of bridge piers

The bridges that constructed in earthquake-prone areas perhaps subjected to sudden earthquake through their construction and service period. So, attentions should be pushed during bridge design specially, as they are one of the main civil infrastructures. The bridge piers are the main parts of bridges whether they are built across river or even as an express highway projects. This paper presented an experimental study of seismic performance of concrete bridge piers. Several important parameters have been studied such as acceleration response, seismic displacements, the bridge pier model settlement and the failure mechanism. Principles of physical modeling are used to fabricate two bridge pier models and shaking table (1-g tests) were performed under 0.82g waveform (i) Chamfered bridge pier built on saturated cohessionless soil (test-1) (ii) Oblong bridge pier built on saturated cohessionless soil(test-2). The output results included the acceleration response in term of the time acceleration and acceleration response spectra, failure mechanism during shacking, seismic displacement of the bridge pier model. The results show that the amplification in the acceleration is increases significantly at the top of the bridge pier. The seismic displacement is suddenly increased sharply due to strong motion. Overturning failure mechanism about the heel of the bridge pier has been observed in test-1 and test-2.

Displacement Measuring of Coastal Area using PS-InSAR

Youm, M.; Tasliman, M. T.; Lee, S., and Kim, H., 2019. Displacement measuring of coastal area using PS-InSAR. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 291-295. Coconut Creek (Florida), ISSN 0749-0208Natural disasters not only cause harm to humans, but also cause changes in the shape of the earth surface. A sudden earthquake occurred in Pohang City with a moment magnitude of 5.4 and caused a serious aftermath to human and property and, furthermore, the geological characteristics of Pohang City worsen the damage from earthquake itself. The present study makes an attempt to analyze the ground displacement as the effects of the earthquake by applying PS-InSAR technique in Sentinel-1A images. The advantage of PS-InSAR in terms of time-series analysis makes it easy to generate the trend of land displacement from the Pohang City. The result in this study indicates that the earthquake has caused the displacement in coastal area of Pohang City.

INSAR ANALYSIS OF AYVACIK 2017 (MW 5.3) EARTHQUAKE SWARM (CANAKKALE, NW-TURKEY)

Abstract. In this study, the deformation of Ayvacik Canakkale earthquake and aftershocks of 5.3 (Mw), which were observed on 6 February 2017 in Gulpinar Ayvacik and felt from the surrounding cities, were analyzed by InSAR and strain reduction technique. The earthquake is occurred at the Biga peninsula which is located at the south segment of North Anatolian Fault zone. The first shock (Ml = 4.8) started on 14 January 2017 in the region, and after the second shock (Ml = 5.4) on February 6, 2017, seismic storm continued with the large and small earthquakes. It was seen that 31 of these earthquakes have a size of 4 and above and occurred on the Tuzla fault. Since classical geodetic methods are not performed regularly and frequently, and are spatially provide point-based displacements, they are often insufficient to monitor sudden earthquakes. For this purpose, the deformation values were obtained along the line of sight (LOS) direction of Synesthetic Aperture Radar (SAR) sensor using Differential Interferometric SAR (DInSAR) method. For the geophysical analysis coulomb technique was applied and the continuity of the changes in the sea is determined.

The gravity data observation of the Cimandiri fault zone, West Java, Indonesia

One of the important faults in Java Islands, Indonesia is the Cimandiri fault zone. It is said the fault has the potential to generate a large earthquake in the near future. Therefore, for mitigating the risk because of the sudden earthquake around the fault in the future and understanding the character of the fault, the investigation around the fault has been applied by using the gravity method. There were 42 gravity sites which deployed in the surrounding of the fault and acquired by using a gravimeter. All necessary corrections such as tidal, instrument drift, latitude, free-air, Bouguer, topographical corrections have been applied. The results presented that the higher amplitude of the residual gravity anomalies values relates to some mountains zone in the study area. It is possibly associated with the volcanic rocks in these areas. In addition, the low amplitude of the residual gravity anomalies is associated with the location of the Cimandiri fault zone and some low elevation areas, which is possibly caused by the existence of the sedimentary products in these areas.

A World Below by Wesley King

Reviewed by: A World Below by Wesley King Wesley Jacques King, Wesley A World Below. Wiseman/Simon, 2018 [272p] Trade ed. ISBN 978-1-4814-7822-9 $17.99 E-book ed. ISBN 978-1-4814-7824-3 $10.99 Reviewed from galleys R Gr. 6-9 When Mr. Baker’s eighth-grade AP class travels to Carlsbad Caverns National Park on a field trip, Eric, the quietest in the class, believes having his mother along as chaperone will be a nightmare. Worried that his whole world might figuratively fall apart as his mom starts showing interest in his crush, Silvia, he’s startled when it literally does: a sudden earthquake rips the ground from underneath him and drops him and Silvia into the Midnight Realm, a land completely untouched by sunlight, inhabited by the descendants of indigenous peoples who have lived in fear of surface-dwellers for generations. Eric, Silvia, and the Midnight King Carlos embark on journeys of self-discovery as they navigate the darkness of the caves and confront what lurks in the metaphorical shadows cast by their respective fathers (Eric was abandoned by his, Silvia’s father ignores her anxiety issues, and Carlos the boy king struggles with the influence of his royal father). This underground adventure features plenty of strange creatures, clever uses of science, and an appreciation for New Mexico’s geological and historical heritage (though there are some colonialist echoes in Eric and Silvia’s education of the Midnight Realmers, despite the fact that Eric is biracial and Silvia is Latina). This richly imaginative field trip gone bad or amazing—depending on how you look at it—is a sharp meditation on the seemingly universal difficulties of being young, smart, and uncertain. Copyright © 2018 The Board of Trustees of the University of Illinois

Retraction Notice: Application of Vibration Damping Technology in High Rise Building

In recent years, Great development have been happened in the damping technique for high-rise building struc- ture, how to build a structure which can ensure the safety of buildings in the sudden earthquake and how to adopt a new system structure which is more safe, more reasonable and more effective plays a decisive role in reducing earthquake dis- aster.This paper introduces the architectural structure of energy dissipation shock absorption system, isolation sys- tem,structure of passive system and structure of active control of the new system, and lists various kinds of application systems in engineering, provides reference for seismic design of engineering structure vibration.

Comparative Study on the Lateral Load Resistance of Multi-Storied Structure with Bracing Systems

The vulnerability of seismic forces onto a high rise structure leads to a sudden collapse which is unpredictable. It can also be understood from the provisions of Indian Standards that, it is desired to allow the damage of the structure to certain extent for sudden earthquakes by safeguarding the livelihood. In the present study, a five storied RC building has been modeled and then analyzed considering the combination of gravity and seismic forces. The performance of the same structure has been investigated for different types of bracing system such as cross and diagonal bracings using a concrete section and steel sections respectively. The performance of the same building has been evaluated in terms of lateral displacement of members, storey drift, axial force and bending moment in columns at different critical. The effectiveness of various bracing systems on the structure has also been investigated. More importantly, the reduction in lateral displacement has been found out for different types of bracing system in comparison to building with no bracing for zone-3 and zone-4. From the present study, it has been found that the crossed ‘X’ bracing reduces more lateral displacement and thus significantly contributes to greater structural stiffness to the structure.

Application of emergency plan nursing management on rescuing batch wounded persons in sudden earthquake disasters

Objective To explore the application value of emergency plan nursing management on rescuing batch wounded persons in sudden earthquake disasters. Methods The our hospital emergency plan nursing management process on rescuing wounded persons in Yushu earthquake disaster was analyzed retrospectively. Results After quick pre-hospital care and effective hospital treatment, a total of 114 wounded persons had recovered and were discharged from hospital without died or invalidism. Conclusions For sudden earthquake caused batch wounded persons, it can enhance treatment success rate and minimize mortality by a effective emergency plan drawing up, utilizing a regulated nursing management process and carrying out specialized clinical nursing. Key words: Nursing management research; Earthquake; Emergency plan; Batch wounded persons; Rescue

Application of Vibration Damping Technology in High Rise Building

In recent years, Great development have been happened in the damping technique for high-rise building structure, how to build a structure which can ensure the safety of buildings in the sudden earthquake and how to adopt a new system structure which is more safe, more reasonable and more effective plays a decisive role in reducing earthquake disaster. This paper introduces the architectural structure of energy dissipation shock absorption system, isolation system, structure of passive system and structure of active control of the new system, and lists various kinds of application systems in engineering, provides reference for seismic design of engineering structure vibration.

Simulation of the time-variable gravity field by means of coupled geophysical models

Abstract. Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on ''Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites''. The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested.

Natural fault lubricants

Motion along faults can occur in sudden earthquakes or through steady, aseismic creep. Rock samples retrieved by drilling deep into a creeping section of the San Andreas Fault show that clay minerals in fault rock promote creep behaviour.