With the increase in nearsource strong motion recordings at both rock and soil sites to aid in constraining empirical attenuation relationships as well as providing. Strong ground motion durations of directivity motions. Engineering characteristics of nearfault vertical ground. This period was used to define the lower bound of the medium period region, i. In the proposed new attenuation relation ship we consider peak values of strong motion, spectral acceleration. Pga is equal to the amplitude of the largest absolute acceleration recorded on an accelerogram at a site during a particular earthquake. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instruments base. A method is developed for computing the magnitude of an earthquake from the intensity. In particular, initial analysis using data from 24 strong ground motion stations were used to determine the amplification from rock sites to soil sites. Strong ground motion estimation, earthquake research and analysis new frontiers in seismology, sebastiano damico, intechopen, doi. Amplification of strong ground motion due to local site.
The effects of the propagation path on the strong ground motion is a research area receiving sub stantial attenuation both from earthquake engineers and seismologists. Each subevent is approximated with a point source, and may correspond to strongmotion generation areas smgas e. The duration of strong ground motion can have a strong influence on earthquake damage. In seismology, strong ground motion is the strong earthquake shaking that occurs close to a. In the above equation, pgv is the peak ground velocity and pga is the peak ground acceleration. Strong motion is currently recording in a mixture of triggered and continuous modes. This occurred at anchorage in alaska earthquake of 1964 newmark and rosenblueth 1971 classified earthquake ground motions into four type. Directivity effects are the nearfault effects characterized by a pronounced twosided velocity pulse that may cause significant damages to. Earthquake simulations in this region, which lies in a sedimentary basin capable of amplifying shaking, predict strong ground motion but they lack validation with observational data. A wide variety of nearfault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component.
Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. Strong ground motion simulation of the 2016 kumamoto. This progressive sequence of ground motion surprises suggests that the current state ofknowledge in strong motion seismology is probably not. Intensity of ground motion during strong earthquakes. The nshmp does a good job estimating the level and frequency of input shaking at a given site but does not account for many conditions that impact ground motion in.
National technical university of athens ioannis psycharis laboratory for earthquake engineering site effects on the ground motion site effects local ground response influence of the soil response on the seismic motion at the ground surface. Strong ground motion and ground failure coordinated by thomas l. Free field motion in our case is defined as shwave propagation in. Procedures for estimating earthquake ground motions. Deterministic strong ground motions linkedin slideshare. Estimating strongmotion characteristics for seismic risk assessment and earthquakeresistant design requires the clear definition of parameters that reflect the. On the other hand, a motion with moderate amplitude but long duration can produce enough duration. Estimation of local site effects on strong ground motion. Basic ground motion characterization peak horizontal ground acceleration not only phga is important. Ground motion is affected by near surface soils, deep geologic structure such as sedimentary basins, and the mechanics of the earthquake itself. Ake, fabian bonilla, pengcheng liu, roland laforge and dean ostenaa january 27th 2012. The strong ground motion data from the october 17, 1989 were used for estimating the amplification factors. Empirical scaling coefficients for equations 5 and 6 from trifunac, 1971a, 1971b mode c0 mo cr b0. These ground motion parameters, particularly near the source of an earthquake are the most detailed available means of identifying.
Ground motion is produced by waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the earth and along its surface. The deterministic seismic hazard map is shown as the distribution of the ground motion level predicted for a specific earthquake fault. In the pseudo pointsource model, strong ground motions are generated from subevents that are placed on the fault plane. Strong ground motion and concept of response spectrum. Each subevent is approximated with a point source, and may correspond to strong motion generation areas smgas e. Connell and others published strong ground motion estimation find, read and cite all the research you need on. The earthquake impacted the damaged buildings in lebak coastal area. No strong motion records are available in aswan area for.
Usually it is considered through the nonlinear onedimensional response of a soil column. Lateral deformations are not influenced significantly by vertical ground motion. A new attenuation relation for strong ground motion in japan based on recorded data article pdf available in bulletin of the seismological society of america 963. This gives access to a database of strong ground motion data parameters, and links to the data centres and web sites of the contributing agencies. This is a warning on the possibility of occurrence of earthquakes in the future too. However, with these caveats in mind, strong ground motion estimation provides substantial value by reducing risks associated with earthquakes and engineered structures. Jain march 20 slide 3 peak ground parameters acceleration pga velocity pgv displacement pgd sudhir k. In seismology the strong motion data provide the high frequency information to determine the rupture process and the complexity of the source mechanism. The observation of strong ground motion and aftershock sequences as well as the investigation of the destruction from these earthquakes, which include the 1995 kobe earthquake, the 1999 chichi earthquake, and the 2001 gujrat earthquake, among others, provide seismology and earthquake engineering with informative and valuable data, experiences. Peak ground acceleration pga is equal to the maximum ground acceleration that occurred during earthquake shaking at a location. The pacific earthquake engineering research center peer is a ninecampus research center headquartered at the university of california, berkeley, working to develop, validate, and disseminate performancebased seismic design technologies for buildings and infrastructure to meet the diverse economic and safety needs of land owners and society. Tilts in strong ground motion article pdf available in bulletin of the seismological society of america 966.
Baker2 1department of civil and natural resources engineering, university of canterbury, private bag 4800, christchurch, new zealand 2department of civil and environmental engineering, stanford university, 473 via ortega, stanford, ca, usa summary. Amplification is a function of the shearwave velocity and damping of the unconsoli. Strong ground motion prediction using virtual earthquakes. Pdf strong ground motion attenuation in aswan area. Instructional materials complementing fema 451, design examples ground motion maps 5b 3 mapped acceleration parameters two sets of maps. Assessment of the site effect of strong ground motion. Chile strong ground motion flatfile article pdf available in earthquake spectra 324. Ground motion for the maximum credible earthquake in.
A major earthquakes exceeding magnitude 6 occurred in the coast of lebak in january 23, 2018. Ground motion simulations that have incorporated nonlinear soil effects have found a large decrease in the predicted strong ground motion. The nshmp does a good job estimating the level and frequency of input shaking at a given site but does not account for many conditions that impact ground motion in a region. N10 sec what is the resonant period of the building in which we are located. This paper presents a set of attenuation equations for spec tral acceleration sa and peak ground acceleration pga in central and eastern north america.
Instructional materials complementing fema 451, design examples ground motion maps 5b 2 seismic ground motions 1 determine basic values from maps for bedrock conditions 2, 3 classify soil conditions at site and determine site coefficients 4 determine siteadjusted values 4 take twothirds for use in design 5 construct design response spectrum. Aki 1988 summarized these results in the following observations. Yet very little has been done, so far, to describe it quantitatively in terms of earthquake magnitude, sourcetostation distance and the effects of geological environment. Pdf inversion of strong ground motion and teleseismic. Summary internet site for european strongmotion data. Recent and paleo seismicity indicate that moderate seismic activity is relatively large for aswan area. A motion of short duration may not produce enough load reversals for damaging response to build up in a structure, even if the amplitude of the motion is high. Ground motion time history northsouth ground acceleration recorded at catech during ml6. Subsequently, the analysis was repeated with strong ground motion for 52 sites. Thus, study of the local site effects is a critical part in seismic hazard mitigation effort, and has resulted in the concept of seismic microzonation. Pdf a new attenuation relation for strong ground motion.
In central asia in this interval two towns and 200 villages were destroyed. This could be an important effect for the scenarios we consider because unconsolidated sediments are likely to be found in sedimentary basins and would be expected to behave nonlinearly during strong shaking. The science of strong ground motion also deals with the variations of fault. Intensities are computed for fourteen strongmotion shocks and these are compared with the modifiedmercalli intensities for the same earthquakes. The duration of strong earthquake ground motion is one of the main parameters characterizing this natural phenomenon. Inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 imperial valley, california, earthquake. Earthquake energy is dispersed in waves from the hypocentre, causing ground movement omnidirectionally but typically modelled horizontally in two directions and vertically. Pdf recently plenty researchers are concentrated earthquake hazard of ulaanbaatar city due to its population, seismotectonic location and so on. The parameters s s and s 1 shall be determined from the 0. Amplification causes the amplitude of the surface ground motion to be increased in some range of frequencies and decreased in others. Recipe for predicting strong ground motion from crustal. A ground motion involving largescale permanent deformation of the ground. The strength of the shaking involved in strong ground motion usually overwhelms a seismometer, forcing the use of accelerographs or strong ground motion accelerometers for recording. Pdf characteristics of strong ground motion records from.
Commission on earthquake hazard, risk and strong ground motion. The spectral response accelerations are obtained from maps prepared following the recommendations of the building seismic safety councils bssc. Pga records the acceleration rate of change of speed of these movements, while peak ground velocity is the greatest speed rate of movement reached by the ground, and peak displacement is the distance moved. In parallel, the development of theoretical methods led to the proposition of new explanatory models of the seismic strong ground motions. Modification of the input bedrock ground motion by the overlying unconsolidated materials. Ground motion is the movement of the earths surface from earthquakes or explosions. The 1997 nehrp recommended provisions for seismic regulations for new buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. These recordings provided several important observations about the nature of the ground shaking, which is critical to both understanding the ground motion phenomena itself, and also the resulting damage observed to structures and infrastructure.
Strong ground motion analysis of the canterbury earthquakes. Ground motion directionality in the 20102011 canterbury. Intensities are computed for fourteen strong motion shocks and these are compared with the modifiedmercalli intensities for the same earthquakes. Worldwide strong motion data resources are centralised at the cosmos virtual data center. Recipe for predicting strong ground motion from crustal earthquake scenarios kojiro irikura 1 and hiroe miyake 2 abstractwe developed a recipe for predicting strong ground motions based on a characterization of the source model for future. Help us write another book on this subject and reach those readers. Modeling and synthesis of strong ground motion s t g raghu kanth department of civil engineering, indian institute of technology, madras, india. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. Pdf strong ground motion simulation and seismic response. Investigation of the frequency content of ground motions.
In seismology, strong ground motion is the strong earthquake shaking that occurs close to less than about 50 km from a causative fault. Development of maximum considered earthquake ground motion. Oct 06, 2017 the strength of the shaking involved in strong ground motion usually overwhelms a seismometer, forcing the use of accelerographs or strong ground motion accelerometers for recording. Advanced methods of predicting strong ground motions from. This project examined the ground motions that were recorded by various instruments during earthquakes from 20102011 in canterbury, new zealand. Jan 24, 2014 earthquake simulations in this region, which lies in a sedimentary basin capable of amplifying shaking, predict strong ground motion but they lack validation with observational data. Site effects on strong ground motion sciencedirect. The total wave field is a superposition of the freefield motion uff 3, t ff 3 and wave scattered u sc 3, t sc 3. The objective of this study to develop an empirical strong motion duration relationship for is directivity pulselike motions. Earthquake shaking generally occurs in all three directions. A measure of the surface intensity of the ground motion during an earthquake is defined which is proportional to the maximum stresses produced in structures. Summary one of the basic problems in the seismic hazard assessment and earthquake resistant design of structures is the proper selection of the ground motion parameters for the generation of the design earthquake. Synthetic strong motion with xm and xn being random numbers between 1 and 1, and the values of other constants are suggested in table 1. The loma prieta earthquake professional papers the loma prieta earthquake professional papers comprehensively document the magnitude 6.