Seismic activity of a region is directly related to information known about earthquakes (EQs) occurred in the region. An uncertainty may always be associated with determination of seismic activity due to incomplete information about historic EQs. For reliable estimation on return period of major to great EQs, accurate information on seismic history is of utmost […]
Read MoreAuthor: Dr Abhishek
Seismic hazard assessment of the Shillong Plateau, India
The Shillong Plateau is an earthquake-prone region in the northeastern India. Based on regional seismotectonic studies, we present here a deterministic seismic hazard assessment (DSHA) and maps of peak horizontal accelerations (PHA) for three largely populated districts – the East Khasi hills, the Ri-Bhoi, and the West Garo hills – within the Shillong Plateau. The […]
Read MoreSeismic Site Classification and Empirical Correlation Between Standard Penetration Test N Value and Shear Wave Velocity for Guwahati Based on Thorough Subsoil Investigation Data
Guwahati, the Gateway of India in the northeast, is a large business and development centre. Past seismic scenarios suggest moderate to significant effects of regional Earthquakes (EQs) in Guwahati in terms of liquefaction as well as building damages. Considering the role of local soil in amplifying EQ generated ground motions and controlling surface damages, […]
Read MoreDetermination of seismic wave attenuation in Delhi, India, towards quantification of regional seismic hazard
National capital of India, Delhi is under moderate to high seismic hazard due to active regional faults such as the Mahendragarh fault, the Delhi Haridwar fault, the Sohna fault, the Delhi Meerut fault and the Rajasthan boundary fault. In addition, Delhi is also located within 200km radial distance from Main Boundary Thrust (MBT) and […]
Read MoreSeismic Site Classification of Recording Stations in Tarai Region of Uttarakhand, from Multiple Approaches
Repeated earthquakes (EQs) are clear indication of alarming seismicity which can be witnessed across Indian subcontinent. Increase in population density with inappropriate construction practice repeatedly rise alarm that in comparison to damage scenarios experienced during previous major to great EQs in India, future catastrophes would be manifold. Performing regional seismic hazard as well as site […]
Read MoreDetermination of NEHRP Site Class of Seismic Recording Stations in the Northwest Himalayas and Its Adjoining Area Using HVSR Method
Local site characteristics plays an important role in controlling the damage pattern during earthquakes (EQs). These site characteristics may vary from simple to complex and can be estimated by various field tests. In addition, extended Nakamura€™s method, which uses horizontal to vertical spectral ratio (HVSR) based on available EQ records also available for site […]
Read MoreBanerjee Soham and Kumar Abhishek (2017), Determination of S and Coda Wave Attenuation in Selected Regions of Lower and Northern Assam Within North Eastern India, Indian Geotechnical Journal, DOI 10.1007/s40098-017-0259-1
The North Eastern (NE) regions of India has been subjected to vicious damages due to numerous earthquakes (EQs). Thus, seismological study in this part of India has been a priori for a long period of time. Present study focuses to find the attenuation characteristics of selected regions within NE India. These selected regions include Guwahati […]
Read MoreBanerjee Soham, Kumar Abhishek (2017), Determination of Seismic Wave Attenuation for the Garhwal Himalayas, India, Geosciences Research, DOI: 10.22606/gr.2017.22005
Present work determines the seismic wave attenuation characteristics in the Garhwal Himalayan, India. These are obtained based on the attenuations of P, S and coda wave spectra from the recorded seismograms of nearby earthquakes (EQs) with focal depth up to 10 km. Since P and S waves come directly to the site, attenuation of P […]
Read MoreBaro Olympa, Kumar Abhishek (2017), Seismic Source characterization for the Shillong Plateau in Northeast India, Journal of Seismology, DOI: 10.1007/s10950-017-9664-2
Present study aims at understanding the seismotectonic province of the Shillong Plateau (SP) by identifying the potential seismic source zones within a radius of 500km from the centre of the SP. From existing literature and earthquake (EQ) data the seismotectonic region is found to vary in terms of seismicity, tectonic features, geology, thickness of […]
Read MoreKumar, A. and Mondal Joy K., (2017), Newly Developed MATLAB Based Code for Equivalent Linear Site Response Analysis, Geotechnical and Geological Engineering, DOI 10.1007/s10706-017-0246-4
Characteristics of ground motions generated during an earthquake (EQ) alter between bedrock and the surface depending upon subsoil properties. Such modifications in the ground motion characteristics are termed as local site effects. Building response as well as induced effects of EQs are thus controlled by these modified ground motions at the surface. Hence, addressing the […]
Read MoreKumar, A. and Srinivas, B.V. (2017), Easy to Use Empirical Correlations for Liquefaction and No Liquefaction Conditions, Geotechnical and Geological Engineering, doi:10.1007/s10706-017-0183-2
Considerable damages during an earthquake (EQ) are the consequence of in-situ soil losing its shear strength which is popularly known as liquefaction. A number of methodologies are available to quantify the safety of a site against liquefaction occurrence. Widely accepted recent methodologies follow iterative process making it cumbersome for the field engineer. In the present […]
Read MoreKumar, A., Harinarayan, N.H. and Baro, O. (2017), Nonlinear soil response to ground motions during different earthquakes in Nepal, to arrive at surface response spectra, Natural Hazards, doi:10.1007/s11069-017-2751-4
Catastrophic damages reported during an earthquake include building damages, excessive ground shaking, uneven settlements, liquefaction etc. While most of the seismic hazard studies map the probable level of ground shaking at the bedrock level, their use in assessing the above damages is very limited until the response of the local soil is also taken into […]
Read MoreMondal K Joy, Kumar Abhishek (2016), Impact of higher frequency content of input motion upon equivalent linear site response analysis for the study area of Delhi , Geotechnical and Geological Engineering, doi:10.1007/s10706-016-0153-0
While travelling through the subsoil layers, earthquake (EQ) generated bedrock motions get modified significantly due to local soil and should be quantified using ground response analysis. Present study concentrates on equivalent linear method of site response analysis in SHAKE2000 software. It is a frequency based analysis tool having default frequency set to 15Hz. While due […]
Read MoreSoham Banerjee, Abhishek Kumar (2016), Determination of Seismic wave attenuation: A Review, Disaster Advances, Vol. 9 (6), 10-27
Earthquake occurs when pent up energy is released during tectonic activities. This energy spreads in the form of waves and while propagating, these waves attenuate non-uniformly in different directions due to the variation in the elastic properties of the propagation medium. The recorded amplitudes of seismic waves are directly related to the attenuation properties […]
Read MoreAbhishek Kumar, Olympa, Baro, Harinarayan N H (2016), Obtaining the surface PGA from site response analyses based on globally recorded ground motions and matching with the codal values, Natural Hazards, Vol. 81, 543-572, DOI 10.1007/s11069-015-2095-x
Destructive moderate to major earthquakes (EQs) across the globe have highlighted various possible forms and extent of damages. Subsoil properties play a vital role in controlling the actual damage scenario. Induced effects such as liquefaction and landslide are also the functions of surface ground shaking. In the present work, site response analyses based on equivalent […]
Read MoreAbhishek Kumar, Harinarayan N H, Olympa Baro (2015), High Amplification factor for Low Amplitude Ground Motion: Assessment for Delhi, Disaster Advances, Vol. 8 (12), 1-11.
Building damages as well as induced effects of earthquake are the consequences of surface ground motion at the site. While due importance is given to the soil beneath the ground, the selection of input motion in site response studies is inadequate. Present work highlights the importance of bedrock motion upon the response of a soil […]
Read MoreOlympa, Baro, Abhishek Kumar (2015), A review on the tectonic setting and the seismic activity of the Shillong plateau in the light of past studies, Disaster Advances, Vol. 8 (7), 34-45.
The Shillong Plateau originated due to the movement in the faults surrounding it; however which fault caused the uplift of the plateau is debatable. Several earthquakes have occurred in the plateau due to these surrounding faults. One such earthquake is the Assam earthquake of 1897 (Mw=8.1). Also, there are evidences that similar earthquakes had occurred […]
Read MorePropagation path characterization and determination of in-situ slips along different active faults in the Shillong plateau
North-East seismicity of India is a combined effect of Indian-Eurasian Plate boundary in the north and the Burmese arc in the east. The region has been considered among the top six most seismically active regions of the world. As per the report by United Nations published under International Decade for Natural Disaster Reduction (INDNDR) for […]
Read MoreUnderstanding local soil effect upon earthquake ground motion for the city of Guwahati city
North-East seismicity of India is a combined effect of Indian-Eurasian Plate boundary in the north and the Burmese arc in the east. The region has been considered among the top six most seismically active regions of the world. Other similar seismicity regions include San Andreas in United States, Guerrero region in Mexico and regions of […]
Read MoreAnbazhagan P., Smitha C V and Abhishek Kumar (2014), Representative Seismic Hazard Map of Coimbatore, India, Engineering Geology, Vol. 171, 81-95.
The seismic hazard value of any region depends upon three important components such as probable earthquake location, maximum earthquake magnitude and the attenuation equation. This paper presents a representative way of estimating these three important components considering region specific seismotectonic features. Rupture Based Seismic Hazard Analysis (RBSHA) given by Anbazhagan et al. (2011) is used […]
Read MoreAnbazhagan P., Abhishek Kumar and Sitharam, T. G. (2013),Ground Motion Predictive Equation Based on recorded and Simulated Ground Motion Database, Soil Dynamics and Earthquake Engineering, Vol. 53, pp 92-108.
Himalayan region is one of the most active seismic regions in the world and many researchers have highlighted the possibility of great seismic event in the near future due to seismic gap. Seismic hazard analysis and microzonation of highly populated places in the region are mandatory in a regional scale. Region specific Ground Motion Predictive […]
Read MoreAnbazhagan, P., Smitha, C. V., Kumar, Abhishek Kumar and Chandran Deepu, (2013), Estimation of design basis earthquakes using specific Mmax for NPP site at Kalpakkam, Tamil Nadu, Nuclear Engineering and Design,Vol. 259, pp 41-64.
The objective of the paper is to estimate Safe Shutdown Earthquake (SSE) and Operating/Design Basis Earthquake (OBE/DBE) for the Nuclear Power Plant (NPP) site located at Kalpakkam, Tamil Nadu, India. The NPP is located at 12.558?N, 80.175?E and a 500 km circular area around NPP site is considered as seismic study area based on past […]
Read MoreAbhishek Kumar , Anbazhagan P. and Sitharam, T. G. (2013), Seismic Hazard Analysis of Lucknow considering Seismic gaps, Natural Hazards, Vol. 69, pp 327-350.
The Himalayas are one of very active seismic regions in the world where devastating earthquakes of 1803 Bihar-Nepal, 1897 Shillong, 1905 Kangra, 1934 Bihar-Nepal, 1950 Assam and 2011 Sikkim were reported. Several researchers highlighted central seismic gap based on the stress accumulation in central part of Himalaya and the non-occurrence of earthquake between 1905 Kangra […]
Read MoreAbhishek Kumar , Anbazhagan, P. and Sitharam, T. G., (2013), Liquefaction Hazard Mapping of Lucknow- A Part Of Indo-Gangetic Basin (IGB), International Journal of Geotechnical Earthquake Engineering, Vol. 4(1), pp 17-41.
Even though the size of the earthquake is moderate, presence of soft soil near the surface can cause devastating damage due to local site and induced effects like liquefaction. Evidence of liquefaction due to past Indian earthquakes was highlighted in many Paleo-seismic studies, particularly in the Himalayan region. The objective of this paper is subsurface […]
Read MoreAbhishek Kumar , Anbazhagan, P. and Sitharam, T.G. (2013), Seismic Site Classification and Empirical Correlation between Standard Penetration Test N value and Shear wave velocity for Deep Soil Sites in Indo-Gangetic Basin,Pure and Applied Geophysics, Vol. 170(3), pp 299-318.
Subsurface lithology and seismic site classification of Lucknow urban center located in the central part of the Indo- Gangetic Basin (IGB) are presented based on detailed shallow subsurface investigations and borehole analysis. These are done by carrying out 47 seismic surface wave tests using multichannel analysis of surface waves (MASW) and 23 boreholes drilled up […]
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