Kinds Of Earthquakes Research Articles

Electrochemical Seismic Design and Artificial Intelligence System Modeling of High-Rise Steel Structure Buildings

This study aims to improve the mechanical earthquake-resistance ability of high-rise buildings’ steel structures so that their safety performance is improved and their service life is prolonged. The simulation experiments on the response of the staggered truss steel structure are conducted in high-rise buildings to earthquake energy waves. First, MATLAB is used to build an experimental platform for earthquake-resistance evaluation of high-rise residential buildings. Through the high-rise building model training, it is found that the model meets the needs of the study. Second, the earthquake-resistance performance parameters, deformation recovery capacity, and dynamic response speed of the staggered truss steel structure are simulated and tested. After earthquake energy waves with different intensities are posed on the high-rise building model, the performance parameters of the staggered truss structure are tested, and the changes in the parameters of the structure are analyzed. Finally, the earthquake-resistance performance and post-earthquake recovery ability of the staggered truss structure are tested through comparative analysis. The results show that the interlayer displacement fluctuation of the staggered truss steel structure is the smallest, and the earthquake resistance performance is better than others under the energy waves of all kinds of earthquakes. Although its earthquake-resistance ability decreases with the duration of earthquakes, the reduction speed is slow. When the quake lasts 12 s, the resistance of the staggered truss structure is still greater than 2500 MPa. This study provides a reference for the staggered truss structure of high-rise buildings.

Study on Design of Highrise Steel Building Frames and Its Seismic Evaluation

Abstract: Seismic Response Analysis of the given structural system is considered to be a subset of stability and configurationally analysis of the system. It is subjected under the calculations obtained in the form of structural response of the buildings produced by the earthquakes. It is found to be the essential and prime component of the designing phenomenon of the structures, or assessment of structural configuration and as a retrofit for the seismic prone regions of the India. The most severe types of earthquakes are essentially emerged closely nearer to the boundaries of the tectonic plates that are covered in the form of globe surface. These plates tries to move with respect one another in the form of relative motion but are resisted by doing so in terms of generation of friction until or unless the various stresses produced between the plates under epicenter reach to such a extent that the movement between the plates gets generated suddenly, which is termed as the earthquake. The local shock produces waves inside the ground which further propagates towards the surface of earth by the movement creation at the structural bases. The intensity of waves decreases with the propagation of distance as we move away from the point of epicenter. Hence, it results into the formation and existence of such regions on the earth surface having very high or less risk of seismic assessment, which indirectly depends upon the proximity to the main tectonic plates boundaries. Apart from the major earthquakes that generally exists near the boundaries of tectonic plates, there are some other earthquakes, that may have their origin and formation at the interior parts of tectonic plates nearer to the fault lines. Such kind of earthquakes are Called as Intra-plate earthquakes. These earthquakes consist of lesser energy, but may be destructive to the area nearer to the point of epicenter The earthquake imparts the action towards the structure in the form of shaking of ground and its motion in the form of vertical and horizontal components. The horizontal component consists of very high strength and the structures are usually designed to resist gravitational forces than horizontal forces, and as a results, it is the most severe component. The vertical components of the earthquake force are found to be 50% of its value in horizontal direction except in the region of point of epicenter because in the region of point of epicenter, both the components are of same orders.

Cryptoexplosive breccia: A genetic mark of the paleoearthquakes

全球到处发育的隐爆角砾岩表明隐爆作用的普遍性，并标志着古地震的一种形成机制。隐爆角砾岩具有特殊的角砾形状和构造。地震地质资料表明大地震产生的地表破裂带没有肉眼可观测到的断层位移。材料聚集应变能估算值表明岩石聚集的应变能不足以产生大地震。携带高能量的地核-地幔流体不仅为自己逸散提供了能量，而且为产生地震提供了充足的能量。深部流体以运移-聚集-爆炸-运移-聚集-爆炸的循环方式向地表逃逸，在地球内部不同深度产生了不同震级的地震。因此，超高压流体隐爆应该是地震形成的主要机制。地震隐爆成因机制不仅能够更好地解释各种天然地震（中深源地震、震群、慢地震和非双力偶性地震等）以及全球地震、火山和地热带的空间吻合，而且能够解释隐爆角砾岩及其伴生矿的形成。;The cryptoexplosive breccias found all over the world indicated that cryptoexplosion was pervasive in the geological history. Cryptoexplosive breccias are characterized by the special structure, which indicates a genetic mark of paleoearthquakes. The seismic-geological data indicated that the great earthquakes produced the ruptures with evident surface displacement, but on visible fault displacement. Estimation of strain energy accumulated in the materials demonstrates that rocks in the crust and mantle cannot accumulate huge strain energy to produce great earthquake. High energy density fluids derived from the core and mantle can provide energy for their migration, as well as enough energy for producing great earthquakes. The deep fluids migrate upward in the way of migration-accumulation-explosion-migration-accumulation-explosion, producing earthquakes with the different magnitudes at different depths. Therefore, the crypto-explosion can be considered as the predominant mechanism of earthquake generation. The proposed genetic mechanism not only can be used to much better explain the generation of different kinds of earthquakes, such as the moderate and deep focus earthquakes, earthquake swarm, slow earthquakes and no-dipole-couple earthquakes, as well as special overlap of the seismic, volcanic and geothermal zones in the world, but also to explain the formation of ore deposits companied with cryptoexplosive breccias.

Cosmic Expansion: The Dynamic Force Source for All Planetary Tectonic Movements

In this paper, the relationship between the geodynamics and cosmic expansion is analyzed and demonstrated from the basic physical principles and various natural phenomena, and the conclusion is drawn that cosmic expansion is the dynamic force source of all planetary tectonic movements in the universe. The energy for the formation and change of landscape and the energy of earthquakes and volcanic eruptions all come from the cosmic expansion. With the cosmic expansion, the energy density of space is decreasing, the atoms and molecules of all matter in the universe are growing, and the magma is expanding and producing gases. As the earth’s internal pressure rises, the mechanical energy that accumulates within the magma forms the driving force of the earth’s various tectonic movements, and the release of these energy and matter (expansive magma and high-pressure gases) leads to the formation and the changes of the landform (such as orogenesis, epeirogenesis, the formation of the earth’s plates, the Earth expansion, the seafloor spreading, and the continental drift), as well as to earthquakes and volcanic eruptions. In this paper, the causes of all kinds of earthquakes, especially deep focus earthquakes, are given and almost all known seismic phenomena are explained, the basic principle and method of earthquake prediction are given, and the direction is pointed out for the elimination of earthquakes and the utilization of earthquake energy. Based on the same principle of physics, this paper also shows that the Ice-Age is caused by the acceleration of the speed of the motion of the solar system relative to the Milky Way in certain regions of the Milky Way. The greater the speed of the solar system relative to the Milky Way, the greater the drop in Earth surface temperature.

Politički zemljotres u SR Bosni i Hercegovini nakon oktobra 1969. godine. Odnos republičkog i saveznog rukovodstva početkom 1970-tih godina

On October 26 and 27, 1969, a devastating earthquake hit Banja Luka and fourteen neighbouring municipalities. The reconstruction of the affected area will become a very important issue causing a kind of earthquake in the relations of Bosnia and Herzegovina's leadership with the Federal Government and the other republics. In the early 1970s, the whole complexity of multi-year struggle for the equal status and treatment of the Republic in the Federation was reflected in it. In the paper, we track the multi-month negotiations overthe funding sources, the contribution of the Federation and the other republics in the construction and renovation of the Bosanska Krajina (the Bosnian Frontier) and we also indicate the political consequences of this natural disaster.

The effect of composite-elastomer isolation system on the seismic response of liquid-storage tanks: Part I

A typical viable technique to decrease the seismic response of liquid storage tanks is to isolate them at the base. Base-isolation systems are an efficient and feasible solution to reduce the vulnerability of structures in high seismic risk zones. Nevertheless, when liquid storage tanks are under long-period shaking, the base-isolation systems could have different impacts. These kinds of earthquakes can damage the tanks readily. Hence, the seismic behaviour and vibration of cylindrical liquid storage tanks, subjected to earthquakes, is of paramount importance, and it is investigated in this paper. The Finite Element Method is used to evaluate seismic response in addition to the reduction of excessive liquid sloshing in the tank when subjected to the long-period ground motion. The non-linear stress-strain behaviour pertaining to polymers and rubbers is implemented while non-linear contact elements are employed to describe the 3-D surface-to-surface contact. Therefore, Nonlinear Procedures are used to investigate the fluid-structure interactions (FSI) between liquid and the tank wall while there is incompressible liquid. Part I, examines the effect of the flexibility of the isolation system and the tank aspect ratio (height to radius) on the tank wall radial displacements of the tank wall and the liquid sloshing heights. Maximum stress and base shear force for various aspect ratios and different base-isolators, which are subjected to three seismic conditions, will be discussed in Part II. It is shown that the composite-base isolator is much more effective than other isolators due to its high flexibility and strength combined. Moreover, the base isolators may decrease the maximum level pertaining to radial displacement.

Two‐Mode Ionospheric Disturbances Following the 2005 Northern California Offshore Earthquake From GPS Measurements

AbstractSeismo‐ionospheric anomalies have been reported, while its disturbance modes, patterns, and mechanism are very complex for different kinds of earthquakes. The earthquake with Mw = 7.2 occurred off the coast of Northern California with strike‐slip faulting on 15 June 2005, which may provide a new insight on ionospheric disturbance waves and patterns from dense Global Positioning System (GPS) observations. In this paper, the detailed seismic ionospheric disturbance modes and characteristics are investigated from dense GPS observations following the 2005 Northern California offshore earthquake. Around 10 min after the earthquake, significant ionospheric disturbances are observed by GPS total electron content (TEC). Furthermore, two‐mode ionospheric disturbances are clearly found with two speeds, 1.51 and 2.31 km/s. The slow‐propagating mode has an amplitude of 0.02–0.04 total electron content unit (TECU), while the fast‐propagating mode has an amplitude of 0.1–0.2 TECU. The frequency spectrogram of the slow mode is around 3.7 mHz, while typical frequency of the fast mode is about 5.3 mHz. The fast‐propagating mode is close to the speed of the seismic Rayleigh wave, which is the up propagating secondary acoustic wave triggered by the Rayleigh wave. The slow mode ionospheric disturbance is propagating horizontally as the acoustic wave at the ionospheric level, which is caused by the fault rupture in focal regions.

Feasibility of using ultra-high ductility cementitious composites for concrete structures without steel rebar

To verify the feasibility of using the ultra-high ductility cementitious composites (UHDCC) for construction without steel reinforcement, the mechanical properties of UHDCC was experimentally tested at material, structural member and structure levels. The tensile strength of UHDCC was from 5 MPa to 20 MPa, the average tensile strain capacity was 8% with the maximum value up to 12%. Four-point bending tests demonstrated that the plain UHDCC beams can match the loading capacity of conventional reinforced concrete beams with the steel reinforcement ratio of 0.5–1.5%. The deflection-span ratio of all the plain UHDCC beams exceeded 1/50 at the peak load. The eccentric compressive loading tests showed that the loading capacity of plain UHDCC column was close to that of RC column with a steel ratio of 0.8%. Additionally, shaking table tests were implemented on a RC frame (steel reinforcement ratios of columns were about 2.0%) and a plain UHDCC frame. The UHDCC frame survived 3 kinds of earthquakes with the peak ground acceleration from 0.105 g to 1.178 g, and exhibited excellent inter-story drift control under extremely strong earthquakes. The performance of the UHDCC frame fulfilled the requirements of various seismic codes. The feasibility of non-steel reinforced UHDCC structure was preliminarily confirmed by this study.

Regional long-period magnitude scales and their capabilities for tsunami warning

The tsunami warning system in the Russian Far East employs the medium-period magnitude MS (BB) by Vaniek–Soloviev. However, its use may lead to inadequacies and underestimates for the tsunamigenic potential of an earthquake. Specifically, this can happen in the case of a so-called tsunami–earthquake. This kind of earthquakes with a nonstandard spectrum was revealed by H. Kanamori in 1972. This problem can be overcome by using a magnitude scale that deals with longer period seismic waves. This study develops a technique for determining the magnitudes at regional distances (from 70 to 4500 km) using the amplitudes of surface seismic waves of periods of 40 and 80 s. At distances of 70–250 km, the amplitude of the joint group of shear and surface waves is used. For the new magnitudes designated M S(40) and M S(80), experimental calibration curves are constructed using more than 1250 three-component records at 12 stations of the region. The magnitudes are calibrated so as to produce an unbiased estimate of the moment magnitude M w in the critical range 7.5–8.8. The rms error of the single-station estimate M w is around 0.27. At distances below 250 km and M w ≥ 8.3, the estimate of M w obtained by the proposed technique becomes saturated at the level of M w ~ 8.3, which is acceptable for operative analysis because no missed alarms arise. The technique can be used in operational tsunami warning based on seismological data. This can markedly decrease the number of false alarms.

Theory and experiment of an inertia-type vertical isolation system for seismic protection of equipment

Although it has been proven that seismic isolation is an effective technology for seismic protection of structures and equipment, most existing isolation systems are for mitigating horizontal ground motions, and in practice there are very few vertical isolation systems. Part of the reason is due to the conflict with regard to the demand for isolation stiffness. In other words, a vertical isolation system must have sufficient vertical rigidity to sustain the weight of the isolated object, while it must also have sufficient flexibility in order to elongate the vibration period under seismic excitation. In order to overcome this difficulty, a novel system is proposed in this study, called an inertia-type vertical isolation system (IVIS). The primary difference between the IVIS and a traditional system is that the former has an additional leverage mechanism with a counterweight. The counterweight will provide a static uplifting force and an extra dynamic inertia force, such that the effective vertical stiffness of the IVIS becomes higher in its static state and lower in the dynamic one. The theory underlying the IVIS is developed and verified experimentally by a seismic simulation test in this work. The results show that the IVIS leads to a less static settlement and at the same time a lower effective isolation frequency. The test results also demonstrate that the isolator displacement demand of the IVIS is only about 30–40 percent that of the traditional one in all kinds of earthquakes. With regard to the reduction of acceleration response, the IVIS is particularly effective for near-fault earthquakes or near-resonant excitations, but is less effective for far-field earthquakes with more high-frequency contents, as compared with the traditional system.

Tectonic setting of the recent damaging seismic series in the Southeastern Betic Cordillera, Spain

In this work we analyze the tectonic setting of the recent damaging seismic series occurred in the Internal Zones of the eastern Betic Cordillera (SE Spain) and surrounding areas, the tectonic region where took place the 11th May 2011 Mw 5.2 Lorca earthquake. We revisit and make a synthesis of the seven largest and damaging seismic series occurred from 1984 to 2011. We analyze their seismotectonic setting, and their geological sources under the light of recent advances in the knowledge on active faults, neotectonics, seismotectonics and stress regime, with special attention focused on the Lorca Earthquake. These seismic series are characterized by two types of focal mechanisms, produced mainly by two sets of active faults, NNW–SSE to NNE–SSW small (no larger than 20–30 km) extensional faults with some strike slip component, and E–W to NE–SW large strike slip faults (more than 50 km long) with some compressional component (oblique slip faults). The normal fault earthquakes related to the smaller faults are dominant in the interior of large crustal tectonic blocks that are bounded by the large E–W to NE–SW strike-slip faults. The strike slip earthquakes are associated to the reactivation of segments or intersegment regions of the large E–W to NE–SW faults bounding those crustal tectonic blocks. Most of the seismic series studied in this work can be interpreted as part of the background seismicity that occurs within the crustal blocks that are strained under a transpressional regime driven by the major strike slip shear corridors bounding the blocks. The seismotectonic analysis and the phenomenology of the studied series indicate that it is usual the occurrence of damaging compound earthquakes of M $$\sim $$ 5.0 associated with triggering processes driven by coseismic stress transfer. These processes mainly occur in the seismic series generated by NNW–SSE to NNE–SSW faults. These mechanical interaction processes may induce a higher frequency of occurrence of this kind of earthquakes than considered in traditional probabilistic seismic hazard assessments and it should be taken into account in future seismic hazard assessments.

Geodetic constraints on the period of episodic tremors and slips using least squares harmonic estimation method with application to Cascadia subduction zone

It is expected that episodic tremors and slips (ETS) as a type of slow earthquakes with periodic property will be detected using harmonic estimation techniques. The principal goal of this paper is the detection of these kinds of earthquakes using least squares harmonic estimation (LSHE). To accomplish this, the raw time series of 38 permanent GPS stations of the Pacific Northwest Geodetic Array have been analyzed. Previously, some independent techniques could confirm the occurrences of the aforementioned quakes at these stations. However, the current research intends to evaluate the spectrum of each of the de-trended time series using the LS-HE method. In each station, the period of the detected harmonic with the maximum power spectrum is equivalent to the average period previously reported for these events. According to the obtained results, the recurrence interval of these events ranges from 9 months to 3 years. In sum, the study confirms this method being efficient for investigating the occurrences of ETSs when the length of the GPS time series is sufficiently large.

Strong-Motion Records Obtained by an Array Observation System During the 2011 Great East Japan Earthquake

Small-Titan, an array system deployed in Sendai City and used for observing strong ground motion succeeded in obtaining strong ground motions at many sites during the 2011 Great East Japan Earthquake. Small-Titan installed in 1998 to investigate local site effects on strong ground motions consists of 20 observation sites with different soil conditions and has obtained over 500 records of various kinds of earthquakes since its installation. The 2011 Great East Japan Earthquake caused severe damage in Sendai City, including that from a tsunami. One site of the Small-Titan system was also hit by a tsunami. This paper describes the background leading to the success of the records of observation of strong motion by Small-Titan for this earthquake and outlines characteristics of records.

Slow slip: A new kind of earthquake

Sandwiched between the shallow region of sudden, infrequent earthquakes and the deeper home to continuous viscous motion lies an intermediate realm of intermittent sliding and rumbling. Discovered in recent years, it still harbors many secrets.

Missing links in earthquake clustering models

Many clustering models imply two kinds of earthquakes: spontaneous ones and those triggered by previous earthquakes. The pair‐wise links from earlier to later earthquakes control the estimates of the clustering parameters. However, earthquake catalogs are limited in time, space, and magnitude, so that triggers of some cataloged earthquakes may be unknown. Thus some links are unrecognized and some triggered events appear spontaneous. Here we present a method for identifying such earthquakes and reducing the bias from missing links. We treat earthquakes probably affected by missing links as potential triggers, but we exclude them in evaluating modeled effects. We use an Epidemic‐type Aftershock Sequence (ETAS) model to examine specifics. The most affected parameter is the proportion of spontaneous earthquakes. The most important missing links apparently follow earthquakes below the magnitude threshold, before the start, and outside the spatial boundaries of the catalog, in that order.

A Developing Plate Boundary: Tianshan-Baikal Active Tectonic Belt

It is obvious that a great amount of strong earthquakes in central Asia occurred densely along Tianshan-Baikal belt; however, none of huge continuous fault has been revealed on the surface along the belt. It caused academic argument related to their relationship. The authors analyzed its seismic activity in terms of seismicity in time-space domain, zoning feature, stress field, and recurrence period of earthquakes. In addition, we studied the Bouguer gravity and isostatic anomaly, and calculated the distribution of density and shear wave velocity in the upper mantle. It is found that there is a gradient belt of density and velocity along NE direction at the depths of 70–250 km, which is actually a Cenozoic boundary of cold mantle and hot mantle, and has an overpass relation with the structure existing in the upper lithosphere. It is inferred that this gradient belt in the upper mantle played an important role in controlling present tectonic movement and stress field in Eurasia continent. As far as the earthquake nature in this belt is concerned, it is neither an interplate earthquake nor an intraplate one in the traditional sense. Such kind of earthquake caused by overpass structure actually belongs to the structural earthquake, and is of interplate within a continent. In this paper, the overpass relation and mirror relation in time-space domain between deep and shallow structures are discussed briefly. It is also noted that the overpass structures shown in the areas of both north-south seismic belt of China and eastern seismic belt of Iran are related to a special structure in the upper mantle. We conclude that the Tianshan-Baikal active tectonic belt is a developing boundary of plates, a typical tectonic within a continent, which separates Eurasian plate into two parts, i.e., the stable Russian-Siberia subplate to the north and the active China-Southeast Asia subplate to the south.

Information characteristics of ground fluid precursors of strong continental earthquakes

It has become seismologist’s common view to attach importance to the study of the characteristics about the relationship among the space distribution of precursory anomalous stations, active structure, deep rock character, and different kinds of earthquakes. In this paper, the information characteristics of ground fluid precursors are analyzed with a few examples of earthquakes. The result shows that information characteristics of ground fluid precursors mainly demonstrate, temporally stage and acceleration pattern, specially, swarm and concurrence feature. It is a key scientific problem, we propose, to give deep study on the stage and concurrence pattern for realizing the seismogenic process as well as making relatively correct prediction to the potential earthquake focus and the occurrence time.

Tectónica reciente y rasgos sismotectónicos en el sector Lorca-Totana de la Falla de Alhama de Murcia

In this work we analyze the kinematics of the Alhama de Murcia Fault in the area of Lorca-Totana, from Upper Pliocene to Presento In this analysis we make use of the information given by pliocene and quaternary sediments. An alternance of thrust and sinistral kinematics behaviours of the Alhama de Murcia Fault can be recognized. This behaviours broungt about for two shortering directions: NNE-SSO and NNO-SSE that control the structure and evolution of Guadalentin Basin and recent sediments. We also study the disposition of more significative earthquakes and its relations with principal shears. The Alhama de Murcia Fault control parcially that disposition and the kind of earthquakes.

Identification of seismogeochemical anomalies in subsurface gas CH4/Ar ratio: Geochemical filtering of earthquakes.

A statistical method, named the Geochemical Filtering Method (GCFM) of earthquakes, has been proposed to identify seismogeochemical anomalies in the record of subsurface gas CH4/Ar ratios at two deep borehole wells in Matsuyama, Japan. This is based on the statistical reasoning that the absence of seismogeochemical anomaly can confidently be shown only by the observational data. The earthquakes occurring in a period when geochemical monitoring does not indicate any significant anomalous changes, are very important to infer what kind of earthquakes does not accompany any seismogeochemical anomalies. This provides us a non-subjective criterion by which the earthquakes unlikely to accompany geochemical anomalies can be selected. The criterion expressed in terms of magnitude and epicentral distance for earthquakes makes it much easier to demonstrate the physical correlation between particular earthquakes and unusual changes in geochemical records. The criterion is thought to represent a threshold relation concerning the appearance of seismogeochemical anomalies. The threshold relation for CH4/Ar anomalies in Matsuyama is found to be similar to those for Rn and geoelectric resistivity anomalies reported in the literature. The GCFM is applicable to other seismogeochemical monitoring data at any stations, and very useful in evaluating the reliability of the geochemical monitoring data.