A5004792455- Earthquake Detection and Analysis
- Seismic Waves and Analysis
- Ionosphere and magnetosphere dynamics
- earthquake and tectonic studies
- Seismology and Earthquake Studies
- Solar and Space Plasma Dynamics
- Geophysics and Sensor Technology
- Geomagnetism and Paleomagnetism Studies
- GNSS positioning and interference
- Radio Wave Propagation Studies
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Tropical and Extratropical Cyclones Research
- Optical Wireless Communication Technologies
- Gamma-ray bursts and supernovae
- Lightning and Electromagnetic Phenomena
- Astronomical Observations and Instrumentation
- Ocean Waves and Remote Sensing
- Stellar, planetary, and galactic studies
- Water Quality Monitoring and Analysis
- Astronomy and Astrophysical Research
- Marine and coastal ecosystems
- Geochemistry and Geologic Mapping
- Optical Polarization and Ellipsometry
- Radio Astronomy Observations and Technology
University of West Attica
2024-2025
Astronomy and Space
2025
Indian Centre for Space Physics
2011-2022
National Remote Sensing Centre
1997-2020
S.N. Bose National Centre for Basic Sciences
2010
Tata Institute of Fundamental Research
2010
University of Kashmir
2010
Indian Space Research Organisation
2010
We present a comprehensive analysis of pre-seismic anomalies as computed from the ground and space-based techniques during recent Samos earthquake in Greece on 30 October 2020, with magnitude M = 6.9. proceed multi-parametric approach where irregularities are investigated stratosphere, ionosphere, magnetosphere. use convenient methods acoustics electromagnetic channels Lithosphere–Atmosphere–Ionosphere-Coupling (LAIC) mechanism by investigating Atmospheric Gravity Wave (AGW), magnetic field,...
This study examines the response of thermal channel within Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) mechanism during notable earthquake in Crete, Greece, on 27 September 2021. We analyze spatio-temporal profiles Surface Latent Heat Flux (SLHF), Outgoing Longwave Radiation (OLR), and Atmospheric Chemical Potential (ACP) using reanalysis data from National Oceanic Administration (NOAA) satellite. Anomalies these parameters are computed by removing background profile for a non-seismic...
Abstract. We show evidences for anomalous ionospheric behaviour in the signal of Indian navy VLF transmitting station named VTX due to earthquakes South Asian region. concentrate on variation D-layer preparation time (DLPT) and disappearance (DLDT) a period sixteen months study their average behaviors. identify those days which DLPT DLDT exhibit significant deviations. Separately, we compute energy release by during this that "anomalous VLF" are associated with release. find anomaly...
We focus on the possible thermal channel of well-known Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) mechanism to identify behavior anomalies during and prior strong seismic events. For this, we investigate variation Surface Latent Heat Flux (SLHF) as resulting from satellite observables. demonstrate a spatio-temporal in SLHF before after set events occurred Kathmandu, Nepal, Kumamoto, Japan, having magnitudes 7.8, 7.3, 7.0, respectively. Before studied earthquake cases, significant...
Atmospheric disturbances caused by seismic activity are a complex phenomenon. The Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) mechanism gives detailed idea to understand these processes study the possible impacts of forthcoming earthquake. atmospheric gravity wave (AGW) is one most accurate parameters for explaining such LAIC process, where seismogenic can be explained in terms waves temperature changes. key goal this work perturbation potential energy associated with stratospheric AGW...
This study explores how the variation of atmospheric gravity waves (AGWs) get modified and intensified during tropical cyclones using high-resolution ERA5 reanalysis data. AGWs play a vital role in understanding cyclone dynamics due to their connection with energy momentum transfer atmosphere. Different issues related six Bay Bengal from 2019 2022, spanning different intensities seasonal conditions, have been analyzed. Using temperature pressure data across 37 vertical levels, several...
Solar eclipses present a valuable opportunity for controlled in situ ionosphere studies. This work explores the response of upper atmosphere’s F-layer during total eclipse 8 April 2024, which was primarily visible across North and South America. Employing multi-instrument approach, we analyze impact on ionosphere’s Total Electron Content (TEC) Very Low Frequency (VLF) signals over three-day period encompassing (7–9 2024). Ground-based observations leverage data from ten International GNSS...
This study explores how the variation of Gravity Waves (GWs) is modified and intensified during tropical cyclones using high-resolution ERA5 reanalysis data. GWs play a vital role in understanding cyclone dynamics due to their connection with energy momentum transfer atmosphere. Different issues related six Bay Bengal from 2019 2022, spanning different intensities seasonal conditions, are analyzed. Using temperature pressure data across 37 vertical levels, several variables like perturbation...
<title>Abstract</title> The present study investigates the effect of solar terminator time (TT) on low- and equatorial-latitude transmitter-receiver great circle path (TRGCP). Very Low Frequency (VLF) signals from VTX (18.6 kHz) NWC (19.8 transmitters, recorded at low-latitude Indian station, Dehradun, are utilized. TRGCP distance to Dehradun is ~6,962 km (long path), ~2,455 (short path). observations suggest that morning (TTM) forms due mode transitions both receiver transmitter for short...
The G5 geomagnetic storm of May 2024 provided a significant opportunity to investigate global ionospheric disturbances using vertical total electron content (VTEC) data derived from 422 GNSS-IGS stations and GIM. This study presents comprehensive spatio-temporal analysis VTEC modulation before, during, after the storm, focusing on hemispheric asymmetries longitudinal variations. primary objective this is analyze spatial temporal under extreme conditions, assess asymmetry disruptions,...
Abstract. VLF signals are long thought to give away important information about the lithosphere-ionosphere coupling. In order establish co-relations, if any, between ionospheric activities and earthquakes, we need understand what reference are, throughout year. The best opportunity do this is during period of solar minimum where number flares sunspots negligible data would be primarily affected by sun variation due normal sunset sunrise effects. paper, present result terminators as a...
Abstract. We present the results of an analysis year-long (2007) monitoring night time data VLF signal amplitude from Indian Navy station VTX at 18.2 kHz, received by Centre for Space Physics, Kolkata. analyzed this to find out correlation, if any, between fluctuation and seismic events. found, analyzing individual cases (with magnitudes >5) as well statistical (of all events with effective greater than 3.5), that has highest probability be beyond 2σ level about three days prior Thus,...
Abstract We present a statistical study of global lightning activity and correlate this with ionospheric fluctuations in the Total Electron Content (TEC). Thunderstorms play significant role modulating ionosphere's plasma distribution. Using well‐known World Wide Lightning Location Network (WWLLN) system, we investigate diurnal, monthly, seasonal variations stroke numbers across six continents. Typically, monsoon causes increase occurrences, as reflected WWLLN observations. chose time frame...
In order to have further evidence of the atmospheric oscillation channel lithosphere-atmosphere-ionosphere coupling (LAIC), we studied criticality in global navigation satellite system (GNSS) surface deformation as a possible agent for exciting gravity waves (AGWs) atmosphere and GNSS fluctuations frequency range AGWs with use natural time (NT) method. The target earthquake (EQ) is 2016 Kumamoto EQ its main shock on 15 April (M = 7.3, universal time). As result application NT method data,...
We present perturbations in very low frequency (VLF) signals received at Ionospheric & Earthquake Research Centre (IERC) (Lat. 22.50°N, Long. 87.48°E) during and prior to two earthquakes, one on 11 March 2011 11:16:24 LT (M = 9) Honshu, Japan another 12 May 2015 12:35:19 7.3) Kodari, Nepal. The VLF signal transmitted from JJI (22.2 kHz) 32.05°N, 131.51°E) showed strong shift VLF-sunrise terminator times towards night-time few days both the earthquakes. These earthquakes took place near...
Abstract In this paper, we estimate the seismogenic energy during Nepal Earthquake (25 April 2015) and studied ground motion time-frequency characteristics in Kathmandu valley. The idea to analyze characteristic of signal is based on wavelet transform which employed here. Wavelet has been used as a powerful analysis tools various fields like compression, analysis, earthquake parameter determination, climate studies, etc. This technique particularly suitable for non-stationary signal. It well...