A. P. Singh

Ministry of Earth Sciences | MoES · Seismology Division

The Gwalior basin in Central India is of significant geological interest due to its diverse geological formations, tectonic history and landscape features. Its location at the boundary between the stable Indian Shield and tectonically active regions to the north and east creates unique seismotectonic and stress patterns, making it different from ot...

We examined the seismic noise data collected from coastal and inland observatories in India, affected by the super cyclonic storm Amphan in the Indian Ocean, to understand the storm dynamics. Prominent disturbances in the 0.05–0.50 Hz frequency range were observed at the seismic stations, arising due to ocean‐continent interactions. The coastal sta...

Numerical modelling of tsunami waves has been made for the western coasts of India using TUNAMIN2 code. In this study, the fault parameters are considered from earlier published literatures. Bathymetry data and possible tsunami generation locations have been obtained from the ETOPO2 (Global Relief Model) and General Bathymetric Chart of the Oceans...

The deadliest tsunami prior to 2004 in South Asia was on November 27, 1945, of Mw8.1, which originated off the Makran coast of Pakistan in the Arabian Sea and caused deaths as far as Mumbai. Tsunami characteristics associated with the west coast of India are studied in detail here to understand the tsunamigenic hazard along coastal regions of Gujar...

Numerous shallow micro-earthquakes of magnitude M1.5 to M4.6 occurred at two places beneath Dharwar (Karnataka) Craton of the Indian Shield during 2021-2023, located ~ 120 km SSW of the 1993 Latur earthquake (M w 6.2) source zone. These earthquakes accompany blast-like subterranean sounds. The unknown seismic activities in both areas caused severe...

The Saurashtra Horst, south of the Kachchh Rift Basin, is a significant tectonic block in the northwestern Deccan Volcanic Province of India. The Saurashtra Horst belongs to the stable continental region and typically experiences shallow intraplate earthquakes with depths up to 20 km. We analysed spectra of P- and S-waves using 182 broadband seismo...

The authors sincerely regret the colour scaling in the cross-section profiles of P-and S-wave velocity perturbations in Figs. 7 and 8. Corrections are as follows red colour is low-velocity perturbations while blue colour is high-velocity perturbations. We attached the corrected Figs. 7 and 8. The authors would like to apologise for any inconvenienc...

In this study, we attempted to establish the plausible depth of disposition of the basal d´ecollement through 3-D seismic imaging using local earthquake tomography to understand the linkage between seismogenesis and collisional tectonics of the Sikkim-Darjeeling Himalayan region. We analysed 2105 events recorded by 33 broadband seismograph stations...

Geotechnical, geological and geophysical investigations for seismic microzonation and site-specific earthquake hazard analysis adopted in Gujarat, western India, are explained. Geology of the area is studied to understand basic earthquake hazards. Seismicity and tectonics are studied up to 50 km distance in detail and 300 km distance in general. To...

The ambient noise measurement approach has been applied for detailed seismic hazard mapping in the Banaras Hindu University (BHU), campus, Varanasi. Thirty three single stations, two standard penetration tests (SPT), and two array micro tremor measurements were carried out to determine the local site characteristics. In this study, H/V spectral rat...

Our detailed 3-D seismic tomographic assimilation using high-quality phase arrival time data recorded by the local seismographic network demonstrated that heterogeneities in the crustal faults have contributed significantly to the pop-up tectonics beneath the Shillong Plateau, characterized by high-V and low-σ. The major seismogenic faults, namely,...

We present a brief atlas of the geographical distribution of earthquake hazard parameters, return periods and probabilities of exceedance of medium to large earthquakes in a hazardous region of the eastern Himalayan seismic belt. A maximum likelihood procedure is applied for the purpose that allows earthquake data during 1500–2019 containing the mi...

The Kachchh Rift Basin (KRB) is a very peculiar region in the Indian subcontinent mostly due to the intense seismic activity and intricate tectonics that is located far from the active plate boundaries. The KRB region is located in the Deccan Volcanic Province of Western India. Recently, a moderate earthquake (Mw5.3) occurred in this region on June...

On 7th of August 2020, a Mw = 4.9 earthquake occurred in Mila province (Northeast Algeria). Consequently, more than 2000 houses were indirectly affected (partially damaged or collapsed) within 10 km from the earthquake’s epicenter, in the locality of El Kherba. According to field surveys conducted 3 days after the earthquake, damages and casualties...

The Palghar region (north Maharashtra, India), located in the northwestern part of the stable continental region of India, experienced a low magnitude earthquake swarm, which was initiated in September 2018 and is continuing to date (as of October 2021). From December 2018 to December 2020, ~5000 earthquakes with magnitudes from M1.2 to M3.8 occurr...

In this study, the crustal shear velocity structure beneath the Indo-Burma Ranges (IBR) is estimated using inversion modeling of the receiver functions computed at seismic stations operated during 2011–2018. The inversion results describe significant variations in the shear-wave velocity (Vs), velocity ratio (Vp/Vs) and crustal thickness in and aro...

The spatial distribution of the b-value has been determined using a homogeneous earthquake catalogue from 1964 to 2018 to examine the characteristics of structural heterogeneities and their bearing on the style of faulting in the Indo-Burma region of Northeastern India. The study region is associated with an uneven distribution of structural hetero...

The microtremor measurements are carried out in and around the Gorakhpur city (Uttar Pradesh), India, overlain by alluvium at about 150 sites to understand the local site conditions. Horizontal-to-vertical spectral ratio (HVSR) confirms that the majority of sites have a predominant frequency of ~0.45 Hz, which may suggest the prevalence of thick so...

The Indo-Burma Ranges (IBRs) and its surrounding North-east India is one of the seismotectonically active subduction systems in the world, where the Indian Plate is subducting beneath the Sunda Plate. This has resulted in major earthquakes in the past. In this study, spectral analysis of S-wave has been used to investigate the source parameters for...

The National Seismological Network (NSN) of India has a history of more than 120 yr. During the last two decades, the NSN has gone through a significant modernization process, involving installation of seismic stations equipped with a broadband seismograph (BBS) and a strong-motion accelerograph (SMA). Each station has a very-small-aperture termina...

The present study provides a characterization of the soil structure underneath nine permanent Broadband Seismograph (BBS) stations spread across the Eastern Indian Shield region. The region is tectonically quite stable and less vulnerable to earthquake activities as compared to the other active regions in India. The objective of this study is to us...

Microtremor measurements are used for preliminary site effect of the Quaternary sediments of Varanasi in Indo-Gangatic plain, which is being planned as a Smart City of India. We evaluated site effects using single and arrays Microtremor measurements at various sites in the Varanasi City, Uttar Pradesh, India. At City, H/V spectral ratios using micr...

Development of earthquake early warning system (EEWS) is in advanced stage in different parts of the world including India. The success of EEWS for mitigating seismic risk and saving human lives has been well documented in Mexico, Japan, and Taiwan, where the alert is issued to the public. Taking advantage of the recorded ground motion data from th...

The Eastern Indian Shield (EIS) consists of two cratonic nuclei, namely Singhbhum craton and Chhotanagpur Granitic Gneissic terrain. This area contains several crisscross faults, lineaments, shear zones, numerous hot springs and three major rivers (e.g., Ganga,Brahmaputra and Damodar). The area is regionally covered by 7 seismic stations and jointl...

An earthquake of small magnitude (ML3.5) occurred on 12 April 2020 near the east district boundary of NCT, Delhi with maximum PGA for the event observed to be 14.13 gals. A few smaller aftershocks also occurred in the area. The estimated fault plane solution of the mainshock suggests normal faulting with some strike slip component. The focal mechan...

We evaluated seismic background noise at national network in India using PSD, Fourier spectra, Spectrogram, and HVSR approach, before and during the nationwide lockdown declared due to COVID-19 pandemic. The analyses were performed to understand characteristics of noise wave-field in such unprecedented situation and its effect on site response at t...

In Surat city, the second largest city of Gujarat, 6930 buildings had been rapidly screened (RVS). RVS is known as a sidewalk evaluation, in which a skilled screener inspect a structure visually in order to recognize characteristics that influence the building's seismic output, for example the construction type, seismic zones, soil, and irregularit...

South Gujarat, a part of the northwestern Deccan Volcanic Province of India has been experiencing episodic swarm activity with reports of sounds, whose association remains unclear. After the Indian monsoon period, during the month of September 2016, a swarm activity occurred around the Keliya dam in the Navsari district of South Gujarat and nearby...

The Arunachal region that constitutes the easternmost segment of the Himalaya has experienced two great earthquakes in the past. This portion is geologically and seismotectonically unique compared to the other parts of Himalaya. In this study, the ambient seismic noise and earthquake waveforms registered at 34 broadband seismograph stations with a...

The Makran coast is extremely vulnerable to tsunamis and earthquakes due to the presence of three very active tectonic plates namely, the Arabian, Eurasian and Indian plates. On 28 November 1945 at 21:56 UTC, a massive Makran earthquake generated a destructive tsunami in the Northern Arabian Sea and the Indian Ocean. The tsunami was responsible for...

The city of Ahmedabad of Gujarat in western India suffered severe damage during the 2001 Mw 7.7 Bhuj earthquake, despite being ∼250 km away from the epicenter. Similar damage patterns were also reported during the 1819 Allah Bund earthquake (Mw 7.8). To investigate the probable causes, we employed an integrated approach using multichannel analysis...

Seismic source parameters of small to moderate sized intraplate earthquakes that occurred during 2002– 2009 in the tectonic blocks of Kachchh Rift Basin (KRB) and the Saurashtra Horst (SH), in the stable continental region of western peninsular India, are studied through spectral analysis of shear waves. The data of aftershock sequence of the 2001...

The eastern part of Kachchh Rift basin was reactivated after 2001 Bhuj earthquake of Mw 7.7 and continuous seismicity has been recorded since then. The northern part of Wagad upland also experienced moderate earthquakes Mw ≥ 5.7 in February 2006 and March 2007. These moderate to major Intraplate earthquakes provide a unique opportunity to study...

The empirical factor Kappa (κ), governs the rapid decay of spectral amplitude at high frequencies. It is one of the important parameters required in the simulations of earthquake strong ground motions. The present study estimates κ for 16 sites of Kachchh region of Gujarat (India). The Kachchh region is one of the most seismically active intraplate...

The Surat City, which is the second most populated city in the state of Gujarat in western India, warrants site-specific seismic hazard assessment due to its rapid urbanization and proximity to major seismogenic zones. This study reports results of microtremor investigations at 72 single stations and 4 arrays in an area of 325 km² spanning the city...

In the present study, fundamental Rayleigh waves with varying period from 10 to 80 s are used to obtain group velocity maps in the northwest Deccan Volcanic Province of India. About 350 paths are obtained using 53 earthquakes (4.8 ≤ M ≥ 7.9) recorded by the SeisNetG (Seismic Network of Gujarat). Individual dispersion curves of group velocity of Ray...

This study presents results of microtremor analysis carried out over diverse geological formations and liquefaction sites in the Kachchh seismic zone of western India, which is host to the deadliest intraplate earthquake (Mw 7.7). Microtremors were recorded at 36 sites with single stations and 7 sites with an array. The microtremor array measuremen...

The Burmese arc is a peculiar plate boundary where there exists an eastward subducted Indian slab, but the current tectonics of the region are predominantly governed by a northward strike-slip motion of the Indian plate past the Burmese plate, as evidenced by seismic and Global Positioning System data. The shallower portion of the dipping Indian sl...

The northwestern Deccan volcanic province in India is one of the most seismically active intraplate regions of the world. In addition, the region is associated with episodic swarm activity and reports of sounds, whose linkage hitherto remains elusive. During the month of January 2016, a swarm activity occurred in the Kachchh and Saurashtra regions...

We describe a study of the E–W-trending South Wagad Fault (SWF) complex at the eastern part of the Kachchh Rift Basin (KRB) in Western India. This basin was filled during Late Cretaceous time, and is presently undergoing tectonic inversion. During the late stage of the inversion cycle, all the principal rift faults were reactivated as transpression...

Globally, one of the largest intraplate earthquakes of Mw 7.7 occurred on 26 January 2001 in the Kachchh rift basin (KRB), western India. The continuing long aftershock sequence over decades has generated much debate on the seismogenic fault(s). We have analyzed more than 10,000 aftershocks (Mw >1:0) recorded by a 50-station broadband network in th...

In this study we present seismic structures of the crust and upper mantle beneath two regions: Kachchh Gujarat region (India), and Caucasus that may represent different stages of the collisional processes. In both cases, the 3D seismic models were obtained based on tomography inversion of arrival times of P and S seismic waves from local and region...

In order to understand the processes involved in the genesis of monsoon-induced micro to moderate earthquakes after heavy rainfall during the Indian summer monsoon period beneath the 2011 Talala, Saurashtra earthquake (Mw 5.1) source zone, we assimilated 3-D microstructures of the sub-surface rock materials using a data set recorded by the Seismic...

In western India during the Bhuj earthquake (Mw 7.6) on January 26, 2001, the Anjar City at �30 km southwest of Bhuj experienced three types of damage scenario: severely damaged, less damaged and non-damaged. Similar damage patterns were also observed for the 1819 (Mw 7.8) and the 1956 (Mw 6.0) earthquakes. Microtremor array measurements were condu...

The west coast of India is affected by tsunamigenic earthquake along the Makran subduction zone. On 28 November 1945 at 21:56 coordinated universal time (UTC), a massive Makran earthquake (M8.0) generated a destructive tsunami that propagated across the Northern Arabian Sea and the Indian Ocean. This tsunamigenic earthquake was responsible for the...

Lighthouses are the road signs of the ocean. They guide sailors through dangerous waters. Each lighthouse design is based on the land it is built on, its purpose, and the technology available. The Geometry of the towers can be round, square, octagonal, or conical in shape. These towers need to be in operation 24x7, guiding the ships coming towards...

Ports are lifeline systems that function as a storage and maintenance facilities for the transport of cargos and people via water. The port structures are frequently exposed to failure under severe seismic loading. It was not only observed during 1995 Kobe earthquake but also during 1989 Loma Prieta and 1999 Kocaeli earthquakes. The scenario is mor...

The pipeline systems are commonly used to transport water, sewage, oil, natural gas and other materials world over. Thes pipelines run over long distances and in some instances they cross high seismic areas including fault crossings. Many buried pipelines in India run through high seismic areas and are exposed to considerable seismic risk. These pi...

Lighthouses are the road signs of the ocean. They guide sailors through dangerous waters. Each lighthouse design is based on the land it is built on, its purpose, and the technology available. The Geometry of the towers can be round, square, octagonal, or conical in shape. These towers need to be in operation 24x7, guiding the ships coming towards...

Pipelines have been acknowledged as the most reliable, economic and efficient means for the transportation of water and other commercial fluids such as oil and gas. They are often referred to as “lifelines”, since they carry materials essential to the support of life and maintenance of property. The earthquake safety of buried pipelines has attract...

Ports are lifeline systems that function as a storage and maintenance facilities for the transport of cargos and people via water. The port structures are frequently exposed to failure under severe seismic loading. It was not only observed during 1995 Kobe earthquake but also during 1989 Loma Prieta and 1999 Kocaeli earthquakes. The scenario is mor...

The Kachchh region is the second most seismically active region in India after the Himalaya. One of the disastrous Indian earthquakes of the millennium was the Bhuj earthquake of January 26, 2001, which caused about 14,000 casualties and huge property damage. The main reason for such devastation is due to lack of earthquake awareness and poor const...

Ports are lifeline systems that function as storage and maintenance facilities for the transport of cargos. The port structures are frequently exposed to failure under severe seismic loading, for example, 1995 Kobe, 1989 Loma prieta, 1999 Kocaeli and 2001 Bhuj earthquakes. The scenario is more critical if the port sites are located within the seism...

The 2001 Bhuj earthquake (Mw 7.6) source zone is examined in the light of crack density (ε), saturation rate (ξ) and porosity parameter (ψ) using new data set derived from a large aftershock sequence recorded by the Gujarat seismic network (GSNet) during November, 2006 - December, 2009. Processes of rupture initiations of the mainshock and its afte...

Seismic source characteristics in the Kachchh rift basin and Saurashtra horst tectonic blocks in the stable continental region (SCR) of western peninsular India are studied using the earthquake catalog data for the period 2006–2011 recorded by a 52-station broadband seismic network known as Gujarat State Network (GSNet) running by Institute of Seis...

In Western Coast of Gujarat destructive tsunamis have been generated from large earthquakes along the Makran Coast, Chagos Ridge and Kutch Region in the past. Although the historical record is incomplete, it is believed that such Tsunamis were destructive on the coasts of India, Pakistan, Iran, Oman and Sri Lanka and possibly had significant effect...

In Western Coast of Gujarat destructive tsunamis have been generated from large earthquakes along the Makran Coast, Chagos Ridge and Kutch Region in the past. Although the historical record is incomplete, it is believed that such Tsunamis were destructive on the coasts of India, Pakistan, Iran, Oman and Sri Lanka and possibly had significant effect...

The Makran coast is extremely vulnerable to tsunamis and earthquakes due to the presence of three very active tectonic plates namely, the Arabian, Eurasian and Indian plates. On 28 November 1945 at 21:56 UTC(03:26 IST), a massive Makran earthquake generated a destructive tsunami in the Indian Ocean. In India, the tsunami reached a height of about 1...

For the assessment of risk of any area three components are necessary viz., Hazard, Exposure and Vulnerability. While most of the times Exposure and Vulnerability are easy to obtain compared to Hazard. For Hazard estimation, real ground motions are required. However, in highly seismic areas with less number of recorded ground motions, artificial gr...