Raghu Kanth STG - Academia.edu (original) (raw)
Papers by Raghu Kanth STG
3D Crustal Velocity Model for Ground Motion Simulations in North-East India
Journal of Earthquake Engineering
Ground Motion Prediction Model Using Artificial Neural Network
Pure and Applied Geophysics
Fundamental Solutions to Static and Dynamic Loads for Homogeneous Reduced Micropolar Half-Space
Pure and Applied Geophysics
Rating damage potential of ground motion records
Earthquake Engineering and Engineering Vibration
Acta Geodaetica et Geophysica
have developed an algorithm to forecast earthquake energy for a given seismogenic zone. The forec... more have developed an algorithm to forecast earthquake energy for a given seismogenic zone. The forecasting strategy is based on empirical mode decomposition and nonlinear regression analysis. The proposed algorithm has been validated with independent subset of seismicity data. Wu (Acta Geod Geophys 2015) has raised concern about the uncertainties and the input seismicity data used to develop the model. This article discusses the problems associated with the modelling of the seismic energy at regional level. Keywords Earthquake forecasting Á Seismic energy release Á Tectonic zones Kavitha and Raghukanth (2015) have compiled a global earthquake catalogue from various sources in literature and used a well defined procedure to forecast earthquake energy in 41 tectonic regions. The seismic energy time series is first decomposed into two statistically uncorrelated models using the empirical mode decomposition (EMD) technique of Huang et al. (1998). The forecasting strategy is based on nonlinear regression analysis (Iyengar and Raghukanth 2005). The developed model is verified by comparing with independent subset of data. Wu (2015) has raised concern about the procedure and the earthquake catalogue used to develop the model. Wu's objections to the methodology is based on his theoretical interpretation. The proposed algorithm can be made time dependent by updating the coefficients in the artificial neural network (ANN) every year. In our article the model parameters are held constant throughout the forecasting period which represents conditions more stringent than necessary. The main assumption in our empirical model is This is a reply to the commentary article
Geomatics, Natural Hazards and Risk
This paper presents a stochastic model to simulate spatial distribution of slip on the rupture pl... more This paper presents a stochastic model to simulate spatial distribution of slip on the rupture plane for large earthquakes (M w > 7). A total of 45 slip models coming from the past 33 large events are examined to develop the model. The model has been developed in two stages. In the first stage, effective rupture dimensions are derived from the data. Empirical relations to predict the rupture dimensions, mean and standard deviation of the slip, the size of asperities and their location from the hypocentre from the seismic moment are developed. In the second stage, the slip is modelled as a homogeneous random field. Important properties of the slip field such as correlation length have been estimated for the slip models. The developed model can be used to simulate ground motion for large events.
Acta Geophysica
This article presents site-specific probable seismic hazard of the Himachal Pradesh province, sit... more This article presents site-specific probable seismic hazard of the Himachal Pradesh province, situated in a seismically active region of northwest Himalaya, using the ground motion relations presented in a companion article. Seismic recurrence parameters for all the documented probable sources are established from an updated earthquake catalogue. The contour maps of probable spectral acceleration at 0, 0.2, and 1 s (5% damping) are presented for 475 and 2475 years return periods. Also, the hazard curves and uniform hazard response spectrums are presented for all the important cities in this province. Results indicate that the present codal provision underestimates the seismic hazard at cities of Bilaspur, Shimla, Hamirpur, Chamba, Mandi, and Solan. In addition, regions near Bilaspur and Chamba exhibit higher hazard levels than what is reported in literature.
Ground Motion Parameters for the 2011 Great Japan Tohoku Earthquake
Journal of Earthquake Engineering
Pure and Applied Geophysics, 2006
In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, Indi... more In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g-0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.
ACKNOWLEDGEMENTS. This work was carried out as a part of ocean modelling activities at C-MMACS sp... more ACKNOWLEDGEMENTS. This work was carried out as a part of ocean modelling activities at C-MMACS sponsored by the Department of Ocean Development (DOD) under several projects. We thank DOD for financial support. A preliminary version of this work was presented at the JGOFS Open Science Conference 'Ocean Biogeochemistry: A New Paradigm' held in Bergen during 13-17 April 2000. K.S.Y. thanks the conference organizers for financial support. We thank Prof. J. J. McCarthy and co-authors for supplying data on nitrogen uptake kinetics in numerical form. K.S.Y. thanks Dr Peter Burkill and Dr T. R. Anderson and their colleagues in Plymouth Marine Laboratory and Southampton Oceanography Centre, respectively for interesting discussions. We also thank Prof. Lakshmi Kantha, Dr Angelica Peña and Dr P. S. Swathi for useful suggestions.
Journal of Earthquake and Tsunami, 2008
Standard penetration test (SPT) reveals the spatial complexity of standard penetration resistance... more Standard penetration test (SPT) reveals the spatial complexity of standard penetration resistance (N-value) with depth. In this paper, a 1D stochastic characterization of spatial complexity of N-values is developed by considering data obtained from sixty two boreholes in Guwahati City. The N-value profile is modeled as the sum of deterministic part and a stochastic component. The deterministic part which characterizes the non-stationary mean of the data is determined by linear regression analysis. The remaining error is modeled as a spatial random field. The characterization of error heterogeneity as a homogeneous Gaussian random field successfully captures the observed auto-correlation function. The proposed stochastic model is used to compute the probability of factor of safety against liquefaction by Monte-Carlo simulation. The results obtained are presented in form of fragility surfaces, expressing the probability of liquefaction as a function of magnitude of the earthquake and ...
Environmental Earth Sciences, 2009
Great earthquakes in the past (e.g. 1869 Cachar earthquake, 1897 great Assam earthquake) have cau... more Great earthquakes in the past (e.g. 1869 Cachar earthquake, 1897 great Assam earthquake) have caused large scale damage and ground liquefaction in the Guwahati city. Moreover, seismologists are of opinion that a great earthquake might occur in the unruptured segment of the NorthEast Himalaya that is near to Guwahati city. In this paper, the liquefaction hazard due to these events have been simulated. The obtained results are in general agreement with the reported damages due to the past earthquakes. The central part of the city (i.e. Dispur, GS road), that has large thickness of soft soil deposit and shallow ground water table, is highly vulnerable to liquefaction.
Ground motion estimation at Guwahati city for an Mw 8.1 earthquake in the Shillong plateau
Tectonophysics, 2008
In this paper, the ground motion at Guwahati city for an 8.1 magnitude earthquake on Oldham fault... more In this paper, the ground motion at Guwahati city for an 8.1 magnitude earthquake on Oldham fault in the Shillong plateau has been estimated by stochastic finite-fault simulation method. The corresponding acceleration time histories on rock level at several sites in the epicentral region have been computed. These results are validated by comparing them with the estimates obtained from Medvedev–Sponheuer–Karnik (MSK) intensity observations of 1897 Shillong earthquake. Using the local soil parameters, the simulated rock level acceleration time history at Guwahati city is further amplified up to the ground surface by nonlinear site response analysis. The results obtained are presented in the form of peak ground acceleration (PGA) contour map. The maximum amplification for PGA over Guwahati city is as high as 2.5. Based on the simulated PGA, the liquefaction susceptibility at several locations in the city has been estimated. The results are presented in the form of contours of factor of safety against liquefaction at different depths below the ground surface. It is observed that over a large part of the Guwahati city, the factor of safety against liquefaction is less than one, indicating that the city is highly vulnerable to liquefaction in the event of this earthquake. The contour maps obtained can be used in identifying vulnerable areas and disaster mitigation.
Engineering source model for strong ground motion
Soil Dynamics and Earthquake Engineering, 2009
ABSTRACT A new engineering source model consistent with seismological concepts for simulating str... more ABSTRACT A new engineering source model consistent with seismological concepts for simulating strong-motion accelerograms (SMAs) is presented in this paper. The source region is modeled as a horizontally layered elastic medium to cater for site dependency. The moment field acting on the rupture plane is decomposed into space and time functions, which is a novel concept. The spatial and temporal components are determined for six well-recorded earthquakes using the corresponding recorded SMA. The obtained spatial variations indicate that they can be modeled as an anisotropic random field. The temporal components of all the six events are transients, with typical frequency spectra. Based on these results, a simplified source model is proposed for the synthesis of SMA during strong earthquakes. The model is validated by simulating strong-motion acceleration time histories at stations deliberately kept out of the modeling exercise. It is found that the present model is efficient in simulating observed time histories. The proposed model is also illustrated by simulating an ensemble of acceleration time histories for the Kutch earthquake of 26th January 2001 using only the few known source parameters.
Pure and Applied Geophysics, 2013
Your article is protected by copyright and all rights are held exclusively by Springer Basel. Thi... more Your article is protected by copyright and all rights are held exclusively by Springer Basel. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Pure and Applied Geophysics, 2006
In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, Indi... more In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g-0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.
Natural Hazards, 2012
Guwahati city is a major city in the northeastern region of India, which is growing rapidly in ev... more Guwahati city is a major city in the northeastern region of India, which is growing rapidly in every aspect, particularly the major infrastructures like sports complex, educational institutions, flyovers, multiplex halls, etc. Two great earthquakes struck this region in 1897 and 1950, and large-scale liquefaction was reported in and around the Guwahati city. However, a detailed microzonation study for liquefaction is not available so far and is taken up accordingly. The liquefaction potential of the Guwahati city is estimated using hundred boreholes data located at different places of city with a design peak ground acceleration of 0.36 g. The results are presented in the form of factor of safety contours at several depths below the ground surface. These contour maps indicate that most of the sites in Guwahati city area are susceptible to liquefaction and hence this aspect has to be considered in earthquake-resistant design of foundations/structures in Guwahati city. Keywords Earthquake Á Liquefaction Á Standard penetration test (SPT) Á Case study 1 Introduction Soil liquefaction is a major design problem for various geotechnical structures including large earth structures such as mine tailings, impoundments, and earth dams. Liquefactioninduced ground failures include loss of bearing strength, lateral spreading, and flow failures, which may cause many engineering problems such as foundation failures, damage to utilities, slope failures, land slides, and large displacements of earth dams. Some of the
MUMBAI (Bombay), the financial capital of India, is a mega city with a population exceeding ten m... more MUMBAI (Bombay), the financial capital of India, is a mega city with a population exceeding ten million. The city is located in Peninsular India (PI), which has experienced the devastating Koyna (1967, Mw = 6.3), Khillari (1993, Mw = 6.1), Jabalpur (1999, Mw = 5.8) and Bhuj (2001, Mw = 7.7) earthquakes. The hazard in this part of India is considered to be less severe than in the Himalayan plate boundary region. This perception is based on the relative occurrence of past tremors in the various regions. How- ever, intra-plate earthquakes are rarer than p late boundary events but usually tend to be more harmful 1 . Paucity of recorded ground motion data introduces uncertainties into the nature of future ground motion and the dynamic forces to be considered in the design of manmade structures. The behaviour of a building, dam or a power plant depends primarily on the local ground motion at the foundation level. A fairly accurate knowledge of such motion, due to all possible sources in t...
3D Crustal Velocity Model for Ground Motion Simulations in North-East India
Journal of Earthquake Engineering
Ground Motion Prediction Model Using Artificial Neural Network
Pure and Applied Geophysics
Fundamental Solutions to Static and Dynamic Loads for Homogeneous Reduced Micropolar Half-Space
Pure and Applied Geophysics
Rating damage potential of ground motion records
Earthquake Engineering and Engineering Vibration
Acta Geodaetica et Geophysica
have developed an algorithm to forecast earthquake energy for a given seismogenic zone. The forec... more have developed an algorithm to forecast earthquake energy for a given seismogenic zone. The forecasting strategy is based on empirical mode decomposition and nonlinear regression analysis. The proposed algorithm has been validated with independent subset of seismicity data. Wu (Acta Geod Geophys 2015) has raised concern about the uncertainties and the input seismicity data used to develop the model. This article discusses the problems associated with the modelling of the seismic energy at regional level. Keywords Earthquake forecasting Á Seismic energy release Á Tectonic zones Kavitha and Raghukanth (2015) have compiled a global earthquake catalogue from various sources in literature and used a well defined procedure to forecast earthquake energy in 41 tectonic regions. The seismic energy time series is first decomposed into two statistically uncorrelated models using the empirical mode decomposition (EMD) technique of Huang et al. (1998). The forecasting strategy is based on nonlinear regression analysis (Iyengar and Raghukanth 2005). The developed model is verified by comparing with independent subset of data. Wu (2015) has raised concern about the procedure and the earthquake catalogue used to develop the model. Wu's objections to the methodology is based on his theoretical interpretation. The proposed algorithm can be made time dependent by updating the coefficients in the artificial neural network (ANN) every year. In our article the model parameters are held constant throughout the forecasting period which represents conditions more stringent than necessary. The main assumption in our empirical model is This is a reply to the commentary article
Geomatics, Natural Hazards and Risk
This paper presents a stochastic model to simulate spatial distribution of slip on the rupture pl... more This paper presents a stochastic model to simulate spatial distribution of slip on the rupture plane for large earthquakes (M w > 7). A total of 45 slip models coming from the past 33 large events are examined to develop the model. The model has been developed in two stages. In the first stage, effective rupture dimensions are derived from the data. Empirical relations to predict the rupture dimensions, mean and standard deviation of the slip, the size of asperities and their location from the hypocentre from the seismic moment are developed. In the second stage, the slip is modelled as a homogeneous random field. Important properties of the slip field such as correlation length have been estimated for the slip models. The developed model can be used to simulate ground motion for large events.
Acta Geophysica
This article presents site-specific probable seismic hazard of the Himachal Pradesh province, sit... more This article presents site-specific probable seismic hazard of the Himachal Pradesh province, situated in a seismically active region of northwest Himalaya, using the ground motion relations presented in a companion article. Seismic recurrence parameters for all the documented probable sources are established from an updated earthquake catalogue. The contour maps of probable spectral acceleration at 0, 0.2, and 1 s (5% damping) are presented for 475 and 2475 years return periods. Also, the hazard curves and uniform hazard response spectrums are presented for all the important cities in this province. Results indicate that the present codal provision underestimates the seismic hazard at cities of Bilaspur, Shimla, Hamirpur, Chamba, Mandi, and Solan. In addition, regions near Bilaspur and Chamba exhibit higher hazard levels than what is reported in literature.
Ground Motion Parameters for the 2011 Great Japan Tohoku Earthquake
Journal of Earthquake Engineering
Pure and Applied Geophysics, 2006
In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, Indi... more In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g-0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.
ACKNOWLEDGEMENTS. This work was carried out as a part of ocean modelling activities at C-MMACS sp... more ACKNOWLEDGEMENTS. This work was carried out as a part of ocean modelling activities at C-MMACS sponsored by the Department of Ocean Development (DOD) under several projects. We thank DOD for financial support. A preliminary version of this work was presented at the JGOFS Open Science Conference 'Ocean Biogeochemistry: A New Paradigm' held in Bergen during 13-17 April 2000. K.S.Y. thanks the conference organizers for financial support. We thank Prof. J. J. McCarthy and co-authors for supplying data on nitrogen uptake kinetics in numerical form. K.S.Y. thanks Dr Peter Burkill and Dr T. R. Anderson and their colleagues in Plymouth Marine Laboratory and Southampton Oceanography Centre, respectively for interesting discussions. We also thank Prof. Lakshmi Kantha, Dr Angelica Peña and Dr P. S. Swathi for useful suggestions.
Journal of Earthquake and Tsunami, 2008
Standard penetration test (SPT) reveals the spatial complexity of standard penetration resistance... more Standard penetration test (SPT) reveals the spatial complexity of standard penetration resistance (N-value) with depth. In this paper, a 1D stochastic characterization of spatial complexity of N-values is developed by considering data obtained from sixty two boreholes in Guwahati City. The N-value profile is modeled as the sum of deterministic part and a stochastic component. The deterministic part which characterizes the non-stationary mean of the data is determined by linear regression analysis. The remaining error is modeled as a spatial random field. The characterization of error heterogeneity as a homogeneous Gaussian random field successfully captures the observed auto-correlation function. The proposed stochastic model is used to compute the probability of factor of safety against liquefaction by Monte-Carlo simulation. The results obtained are presented in form of fragility surfaces, expressing the probability of liquefaction as a function of magnitude of the earthquake and ...
Environmental Earth Sciences, 2009
Great earthquakes in the past (e.g. 1869 Cachar earthquake, 1897 great Assam earthquake) have cau... more Great earthquakes in the past (e.g. 1869 Cachar earthquake, 1897 great Assam earthquake) have caused large scale damage and ground liquefaction in the Guwahati city. Moreover, seismologists are of opinion that a great earthquake might occur in the unruptured segment of the NorthEast Himalaya that is near to Guwahati city. In this paper, the liquefaction hazard due to these events have been simulated. The obtained results are in general agreement with the reported damages due to the past earthquakes. The central part of the city (i.e. Dispur, GS road), that has large thickness of soft soil deposit and shallow ground water table, is highly vulnerable to liquefaction.
Ground motion estimation at Guwahati city for an Mw 8.1 earthquake in the Shillong plateau
Tectonophysics, 2008
In this paper, the ground motion at Guwahati city for an 8.1 magnitude earthquake on Oldham fault... more In this paper, the ground motion at Guwahati city for an 8.1 magnitude earthquake on Oldham fault in the Shillong plateau has been estimated by stochastic finite-fault simulation method. The corresponding acceleration time histories on rock level at several sites in the epicentral region have been computed. These results are validated by comparing them with the estimates obtained from Medvedev–Sponheuer–Karnik (MSK) intensity observations of 1897 Shillong earthquake. Using the local soil parameters, the simulated rock level acceleration time history at Guwahati city is further amplified up to the ground surface by nonlinear site response analysis. The results obtained are presented in the form of peak ground acceleration (PGA) contour map. The maximum amplification for PGA over Guwahati city is as high as 2.5. Based on the simulated PGA, the liquefaction susceptibility at several locations in the city has been estimated. The results are presented in the form of contours of factor of safety against liquefaction at different depths below the ground surface. It is observed that over a large part of the Guwahati city, the factor of safety against liquefaction is less than one, indicating that the city is highly vulnerable to liquefaction in the event of this earthquake. The contour maps obtained can be used in identifying vulnerable areas and disaster mitigation.
Engineering source model for strong ground motion
Soil Dynamics and Earthquake Engineering, 2009
ABSTRACT A new engineering source model consistent with seismological concepts for simulating str... more ABSTRACT A new engineering source model consistent with seismological concepts for simulating strong-motion accelerograms (SMAs) is presented in this paper. The source region is modeled as a horizontally layered elastic medium to cater for site dependency. The moment field acting on the rupture plane is decomposed into space and time functions, which is a novel concept. The spatial and temporal components are determined for six well-recorded earthquakes using the corresponding recorded SMA. The obtained spatial variations indicate that they can be modeled as an anisotropic random field. The temporal components of all the six events are transients, with typical frequency spectra. Based on these results, a simplified source model is proposed for the synthesis of SMA during strong earthquakes. The model is validated by simulating strong-motion acceleration time histories at stations deliberately kept out of the modeling exercise. It is found that the present model is efficient in simulating observed time histories. The proposed model is also illustrated by simulating an ensemble of acceleration time histories for the Kutch earthquake of 26th January 2001 using only the few known source parameters.
Pure and Applied Geophysics, 2013
Your article is protected by copyright and all rights are held exclusively by Springer Basel. Thi... more Your article is protected by copyright and all rights are held exclusively by Springer Basel. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Pure and Applied Geophysics, 2006
In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, Indi... more In the absence of strong motion records, ground motion during the 26 th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g-0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.
Natural Hazards, 2012
Guwahati city is a major city in the northeastern region of India, which is growing rapidly in ev... more Guwahati city is a major city in the northeastern region of India, which is growing rapidly in every aspect, particularly the major infrastructures like sports complex, educational institutions, flyovers, multiplex halls, etc. Two great earthquakes struck this region in 1897 and 1950, and large-scale liquefaction was reported in and around the Guwahati city. However, a detailed microzonation study for liquefaction is not available so far and is taken up accordingly. The liquefaction potential of the Guwahati city is estimated using hundred boreholes data located at different places of city with a design peak ground acceleration of 0.36 g. The results are presented in the form of factor of safety contours at several depths below the ground surface. These contour maps indicate that most of the sites in Guwahati city area are susceptible to liquefaction and hence this aspect has to be considered in earthquake-resistant design of foundations/structures in Guwahati city. Keywords Earthquake Á Liquefaction Á Standard penetration test (SPT) Á Case study 1 Introduction Soil liquefaction is a major design problem for various geotechnical structures including large earth structures such as mine tailings, impoundments, and earth dams. Liquefactioninduced ground failures include loss of bearing strength, lateral spreading, and flow failures, which may cause many engineering problems such as foundation failures, damage to utilities, slope failures, land slides, and large displacements of earth dams. Some of the
MUMBAI (Bombay), the financial capital of India, is a mega city with a population exceeding ten m... more MUMBAI (Bombay), the financial capital of India, is a mega city with a population exceeding ten million. The city is located in Peninsular India (PI), which has experienced the devastating Koyna (1967, Mw = 6.3), Khillari (1993, Mw = 6.1), Jabalpur (1999, Mw = 5.8) and Bhuj (2001, Mw = 7.7) earthquakes. The hazard in this part of India is considered to be less severe than in the Himalayan plate boundary region. This perception is based on the relative occurrence of past tremors in the various regions. How- ever, intra-plate earthquakes are rarer than p late boundary events but usually tend to be more harmful 1 . Paucity of recorded ground motion data introduces uncertainties into the nature of future ground motion and the dynamic forces to be considered in the design of manmade structures. The behaviour of a building, dam or a power plant depends primarily on the local ground motion at the foundation level. A fairly accurate knowledge of such motion, due to all possible sources in t...