Browsing by Author "Sonia Devi"

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Investigation of the high frequency attenuation parameter kappa (κ) beneath the volcanic region of Kyushu using surface and borehole dataset
(Elsevier Ltd, 2025) Sandeep; Sonia Devi; Pragya Singh; Udai Pratap Singh; Shiv Kumar Pal; Parveen Kumar; Monika; Ashok M.Praveen Kumar; Himanshu Mittal
This study focuses on a detailed analysis of the high-frequency attenuation parameter, kappa (κ), to better understand seismic wave propagation in the volcanic region of Kyushu. In this analysis, κ values are examined beneath the volcanic area of the Kyushu region using strong motion data from the 2016 Kumamoto earthquake. The Surface and borehole data are utilized to evaluate the effects of site conditions and regional attenuation characteristics, respectively. The site attenuation parameter (κ0) ranges from 0.022s to 0.068s, as estimated from 21 surface stations. The κ0 values correlate with average shear-wave velocity in the top 30 m (VS30), showing a decrease as VS30 increases. Additionally, using borehole data, the region-specific S-wave quality factor (Qs) and κ0 are estimated in this region, resulting in values of 846 ± 75 and 0.050 ± 0.002s, respectively. The relatively lower Qs values and higher κ0 values observed in this study may be due to the extensive volcanic activities in the Kyushu region. The findings closely match previous studies, highlighting significant attenuation in the volcanic region. The average κ values for borehole data are 0.043s–0.053s for horizontal components (κH) and 0.038s–0.051s for vertical components (κv). Surface data shows κH values from 0.061s to 0.070s and κV from 0.039s to 0.046s. A relative comparison shows κH and κv are roughly equal in borehole conditions, while surface conditions reveal κH exceeds κv due to site effects on horizontal components. The estimated κ values are crucial for future site-specific seismic hazard analysis in Kyushu's volcanic regions. © 2025 Elsevier Ltd
Modeling of 2011 IndoNepal Earthquake and Scenario Earthquakes in the Kumaon Region and Comparative Attenuation Study Using PGA Distribution with the Garhwal Region
(Birkhauser Verlag AG, 2019) Sandeep; A. Joshi; S.K. Sah; Parveen Kumar; Sohan Lal; Sonia Devi; Monika
Kumaon and Garhwal regions are the chief terrains of Uttarakhand Himalaya. The present article simulates the strong ground motion of the 2011 IndoNepal earthquake in the Kumaon region using modified semi empirical technique (MSET). Acceleration records at ten stations in the near field region have been simulated which validates well with actual records and therefore confirms the reliability of MSET. In addition, MSET has been used to simulate strong motion records of future scenario earthquakes (Mw 7.0 and Mw 8.0) in Kumaon region by assuming the earthquake location same as that of 2011 IndoNepal earthquake. Isoacceleration maps are also provided, which reveals more than 400 gal value of PGA at epicentral distances less than 25 kms for an earthquake of magnitude 8.0. The comparison of isoacceleration map of future scenario earthquake (Mw 7.0) in Kumaon region has been done with isoacceleration map of 1991 Uttarkashi earthquake (Mw 6.8) in Garhwal region which suggests distinct attenuation characteristics of these two regions. © 2019, Springer Nature Switzerland AG.
Modelling of 1991 Uttarkashi and 2011 Indo-Nepal earthquakes using the modified semi-empirical technique by integrating site-specific quality factor
(Springer, 2023) Monika; Sandeep; Parveen Kumar; Sonia Devi; A. Joshi
Strong ground motion simulation is a reliable tool for seismic hazard assessment and mitigation of any region. The distribution of hazards during an earthquake is greatly influenced by the attenuation properties of the medium. Typically, regional attenuation characteristic is employed for strong motion simulation rather than site-specific attenuation. In the current study, the newly developed semi-empirical simulation approach is modified to use a site-specific attenuation relation. Initially, the medium attenuation characteristics are quantified by estimating frequency-dependent S-wave quality factor (Qβ(f)) at each recording station. These obtained Qβ(f) relations at each station are further utilised to estimate the regional relation for the Garhwal and Kumaon regions as (90±4)f (0.86±0.05) and (54±2)f (0.89±0.1), respectively. These values suggest that the Garhwal region is relatively less attenuative and more credible for seismic hazards compared to the Kumaon region. The Qβ(f) obtained at each recording station are further used to simulate the 1991 Uttarkashi (Mw 6.8) and 2011 Indo-Nepal (Mw 5.4) earthquakes. An improved match is perceived between the observed and simulated records with site-specific Qβ(f) values instead of regional ones. This comparison successfully validates the present modification in SET. This work provides insight into getting more realistic simulated results and explores recent trends in strong motion seismology for seismic hazard evaluation. © 2023, Indian Academy of Sciences.
Modelling of 2016 Kumamoto earthquake by integrating site effect in semi-empirical technique
(Springer Science and Business Media B.V., 2022) Sonia Devi; Sandeep; Parveen Kumar; Monika; A. Joshi
The 2016 Kumamoto earthquake (MJMA7.3) struck central area of Kyushu Island, Japan. The presence of near surface low velocity layer greatly amplified the ground motions and caused severe damage in this region. Therefore, it is essential to study the site characteristics of Kumamoto region. For this purpose, the present research article describes the modification in existing semi-empirical technique of strong motion simply by incorporating the site effect. These site effects are calculated using Horizontal to Vertical ratio (H/V) method. The estimated predominant frequencies (fpeak) for these stations varies between 2.5 and 7.5 Hz. The sites with low fpeak indicate higher soil thickness cover and hence, locations are more susceptible to damage. The station KMMH06 used in this work lies in close proximity to one of the major landslide locations (Minami Aso Village), triggered during this earthquake. The low to intermediate fpeak value estimated at KMMH06 proposes the area prone to site amplification and severe damage. Also, the initial location and parameters of rupture model of this earthquake are considered based on past seismicity and other empirical relations available. The detailed analysis proposes nucleation point in extreme NW corner of the rupture plane. Afterwards, the developed source model and modified technique compositely used to simulate high frequency records at eight near field stations. This includes time histories, response spectra, predominant period (Tp) and mean period (Tm). The above comparison successfully validates modified semi-empirical and source model for 2016 Kumamoto earthquake. As far as we are aware, this work is the first to model rupture plane of 2016 Kumamoto earthquake by means of modified semi-empirical technique. It provides adequately reliable results which will be advantageous for seismic hazard assessment of this region. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.
Monitoring Phytoremediation of Metal-Contaminated Soil Using Remote Sensing
(Springer International Publishing, 2022) Bhabani Prasad Mondal; Rabi Narayan Sahoo; Bappa Das; Priya Paul; Arghya Chattopadhyay; Sonia Devi
Phytoremediation is an effective tool which can be employed to revive the degraded or metal-contaminated soils. However, assessment of contamination caused by heavy metal in soil and its monitoring on long-term basis is essential to assess the efficacy of phytoremediation processes. Conventional techniques for monitoring the contaminated sites are noticeably expensive, time intensive, and destructive in nature. Remote sensing (RS) may assist as an efficient alternative technique for detecting metal contamination and monitoring phytoremediation on a long-term basis. The RS data from various sources at various scales such as proximal sensing data (laboratory and field-based spectroradiometric data), airborne data (dronecollected data), and space-borne data (satellite data) are crucial for monitoring the extent of contamination and to detect changes in land use pattern and surface cover of the polluted site over a time period. Most of the RS based techniques use vegetation reflectivity within the red-edge position of the electromagnetic radiation for indirect estimation of contamination level that is associated with heavy metal and organic carbon (hydrocarbon) concentration in soil. In proximal sensing, laboratory- and field-based spectroscopic data are employed to predict the level of contamination through correlating the characteristic reflectance spectra of the spectrally active soil constituents with metals. To determine the efficiency of phytoremediation, monitoring of revegetation or biorecultivation is also necessary using RS data. One of the most promising techniques to monitor revegetation is to calculate various indices related to soil, vegetation, and moisture through interpreting the remote sensing-based data product. The most frequently used vegetation index such as normalized difference vegetation index (NDVI) helps to measure the phytoproductivity of the polluted area. RS based indices are useful to detect metal-induced vegetation stress. However, a few key limitations are there in obtaining satisfactory results using RS based methods such as complexity of spectra, non-availability of unique spectral feature for particular metal, and noisy spectra due to variation in atmospheric conditions. In spite of so many challenges, RS based techniques are considered as non-destructive, time-saving, and cost-effective alternative techniques especially for large phytoremediation areas. Recently both airborne and space-borne hyperspectral RS data are used for continuous and detailed monitoring of the contaminated areas. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022, corrected publication 2022.
Real-time earthquake magnitude estimation utilizing a mixed dataset set of observed and simulated P-wave onsets for the Kumaon Himalaya from Mw3.0–7.5 earthquakes
(Elsevier Ltd, 2025) Suraj Kumar Pal; Sonia Devi; Sandeep; Parveen Kumar; Anushi Joshi; Monika; Roshan Kumar
We propose new earthquake early warning (EEW) magnitude regression relations by utilizing 254 simulated and observed records for the Kumaon Himalaya. Initially, we validated the modified semi empirical technique (MSET) aimed at P phase simulation for the 2011 Indo Nepal earthquake (Mw5.4) occurred in the Kumaon Himalaya. The close resemblance between observed and simulated vertical records that are generated by MSET at 5 stations with relatively low root mean square error (RMSE) suggests the applicability of MSET. We then simulated 65 strong motion records for 7 future earthquakes (Mw 6.0–7.5) in the study region. Subsequently, we extracted 3 commonly used EEW parameters Average Period (τc), Peak Displacement Amplitude (Pd), and Peak Ground Velocity (PGV) from 45 simulated and 209 observed records, utilizing 3s and 5s P-wave time windows (PTWs). The 3s PTW is applied for earthquake magnitudes in the range of 3≤Mw<6, while the 5s PTW is used for magnitudes between 6≤Mw ≤ 7.5. The developed magnitude empirical relations are then used to estimate both the magnitude and the PGV using P-wave onset of 20 additional simulated records. The comparable match between scenario magnitude and predicted magnitudes estimated using τc-Mw and Pd-Mw with maximum relative error 0.041 and 0.052 respectively suggests the relevance of the developed regression relations. Similarly, with maximum relative error of 0.37 between scenario PGV and predicted PGV further confirms the validity of Pd-PGV relation. Additionally, the estimation of lead times using proposed relations vary from 6.85 to 90s for 17 metropolis and devotional sites located near to the study region during future scenario earthquakes. © 2025 Elsevier Ltd
Site response study based on H/V method using S-wave: A case study in the Kumaon Himalaya, India
(Wadia Institute of Himalayan Geology, 2019) Parveen Kumar; Sonia Devi; Monika; Abhyuday Srivastava; Sandeep; A. Joshi; Richa Kumari
In this paper, site response study is conducted in highly mountain terrains of the Kumaon Himalaya, India by using Horizontal to Vertical spectral ratio method (H/V) (H/V is ratio of Fourier spectrum of horizontal and vertical component of the record). Strong ground motion data of 110 local earthquakes recorded during year 2006-2013 and the S-phase of these records are utilised to characterize the site effects of the Kumaon Himalaya region. Resonance frequencies at different observation sites are enumerated by using the H/V technique proposed by Nakamura (1989) and later modified by Lermo & Chavez Gaarcia (1993) for S-wave. It is perceived that obtained resonance frequencies vary from one station to another. Recording stations provide different values of resonance frequencies ranging from 0.7 to 8.1 Hz. A close resemblance is observed between resonance frequency and rock type i.e. stations of high values of resonance frequencies are situated at high compact rocks as compared to the stations of low values. Hence, stations having low resonance frequency may be having the potential for high seismic hazard. In the present study, the values of resonance frequencies have increasing trend from south to north direction, which may be the signature of increasing grade of compactness of the rock from south to north. © 2019, Wadia Institute of Himalayan Geology. All rights reserved.
Source Modeling of Deep Plate Boundary 2021 Miyagi Earthquake (Mw7.0) Employing Modified Semi-Empirical Technique with Site Effects: A Step Forward Towards Hazard Mitigation
(Taylor and Francis Ltd., 2025) Sonia Devi; Pal Suraj Kumar; Sandeep Arora; Kumar Parveen; Monika; Himanshu Mittal
The source modeling of 2021 Miyagi earthquake (Mw7.0) offers a significant tool to understand the initial evaluation of M9 earthquake cycle in this region. This article seeks to simulate the 2021 Miyagi earthquake (Mw7.0) using the modified semi-empirical technique (MSET) after incorporating site effects determined using the Horizontal to Vertical spectral ratio technique. We propose the best-fitting source model of this earthquake from a spectrum of rupture model parameters using MSET. We believe that this effort is the first to use MSET to model this earthquake and will provide significant contribution for seismic hazard assessment of the Miyagi region. © 2024 Taylor & Francis Group, LLC.
Spatial Distribution of Stress Orientation by Inversion of Focal Mechanism Solutions Using MSATSI: A Case Study Across Japan Trench
(Springer Science and Business Media Deutschland GmbH, 2023) Sucheta Das; Sandeep; Sonia Devi; Himanshu Mittal; Praveen Kumar; Monika
Estimation of stress field orientations is a necessary aspect for recognition of crustal mechanics as well as the physics behind occurrence of earthquakes. A case study employing the new MATLAB software package Spatial And Temporal Stress Inversion (SATSI) for stress inversion utilizing the focal mechanism data is presented here to produce stress orientation models in Northeast (NE) Japan. In this work, the study region is divided into 49 small sub-regions so that the stress tensors and focal mechanisms can independently fit in each sub-region. Determination of any stress variation is strongly needed by the data while eliminating the artifacts due to overfitting of noisy or nonuniquely fitting data. To resolve it, a damped inversion procedure was applied which inverted the stresses in all sub-regions, while at the same time reducing the difference in stress between adjacent sub-regions. Earthquake focal mechanisms have been used to determine the stress patterns at depths capable of generating earthquakes in NE Japan since 1960–2021. In this work, 0D, 1D, and 2D stress inversion using the MSATSI (MATLAB package for Spatial And Temporal Stress Inversion) routine was performed and examined the spatial variation of stress orientations over NE Japan along the Japan Trench and put forward recent knowledge about the stress pattern. From the obtained 2D inversion results, a spatially varying stress regime is observed in the crust which demonstrates normal faulting on the subducting Pacific plate which changes to reverse faulting on the Okhotsk plate through an intermediate state of oblique faulting. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Spatial variability studies of attenuation characteristics of Qα and Qβ in Kumaon and Garhwal region of NW Himalaya
(Springer, 2020) Monika; Parveen Kumar; Sandeep; Sushil Kumar; A. Joshi; Sonia Devi
The present work explores the attenuation characteristics of Garhwal and Kumaon regions of northwest Himalaya, India. A comparative study of P- and S-wave quality factors (Qα and Qβ) is used to appreciate the different attenuation characteristics of these two regions. The strong motion data of 105 local earthquakes recorded in Garhwal and Kumaon region are considered for the analysis. The coda normalization method is implemented to compute Qα and Qβ at each recording site of form Q(f) = Qofn. The regional relationship obtained by using site-specific quality factor relations is Qα(f) = (55 ± 3)f(0.90±0.06), Qβ(f) = (74 ± 5)f(0.87±0.08) for Garhwal region and Qα(f) = (34 ± 1)f(0.94±0.03), Qβ(f) = (58 ± 2)f(0.90±0.02) for Kumaon region, which clearly suggest the existence of spatial variation of attenuation properties in these two regions. The Kumaon region has low Qα and Qβ as compared to Garhwal, which means Kumaon region has high rate of attenuation than Garhwal region, as Q is inversely proportional to the attenuation. Hence, based on obtained attenuation properties it is proposed that Garhwal region has high seismic hazard potential zone as compared to its adjacent Kumaon region. The high value of Qβ/Qα (˃ 1) obtained in the present work indicates the presence of fluid or partially saturated rocks in the earth crust for both Garhwal and Kumaon regions. The variable value of ratio (Qβ/Qα) obtained for Garhwal and Kumaon region specifies the different fluid saturations or fluid types existing for both the regions, and it may be the possible reason of distinct attenuation properties of these two regions. © 2020, Springer Nature B.V.
Strong motion generation area modelling of the 2008 Iwate earthquake, Japan using modified semi-empirical technique
(Springer, 2019) Sandeep; A. Joshi; Sonia Devi; Parveen Kumar; S.K. Sah; Sohan Lal; Kamal
The Iwate–Miyagi earthquake (Mw 6.9) of 14 June 2008 is one of the largest intraplate earthquakes that struck north-east Japan. This earthquake has produced the largest peak ground acceleration (PGA) ever recorded. The acceleration values 4022 and 1036 gal were observed at the surface and borehole accelerometers of IWTH25. To understand the cause of this extremely large acceleration, it is highly essential to obtain the detailed rupture process of Iwate–Miyagi earthquake. The present paper estimates the rupture model for this earthquake using the modified semi-empirical technique (MSET). The detailed analysis proposes one strong motion generation area (SMGA) in the rupture plane and nucleation point in the extreme western corner of the SMGA. Using this estimated source model, a satisfactory match is observed between the simulated and actual records. The quantitative analysis of these waveforms provides an almost 1:1 match for PGA values. Furthermore, the variation of these PGA values with epicentral distance shows similar attenuation rate. These results confirm the reliability of MSET and the estimated source model of this earthquake. To the best of our knowledge, this study is the first to model SMGAs in the rupture model using MSET and provides sufficiently reliable information which will be useful for seismic hazard prevention management. © 2019, Indian Academy of Sciences.
Strong Motion Modelling of the 1999 Izmit Earthquake Using Site Effect in a Semi-Empirical Technique: A More Realistic Approach
(Birkhauser, 2022) Sandeep; Sonia Devi; Parveen Kumar; Monika; Rohtash Kumar
A devastating earthquake (Mw 7.4) struck near Izmit city, northwestern Turkey, on 17 August 1999. The relatively large size of this earthquake and site amplification conditions caused severe damage in the Marmara region as well as the city of Istanbul. The disastrous outcome of this large earthquake requires careful analysis of the seismic hazard including local site effects in this region. Therefore, the present work addresses the issue of local site effects and modelling of strong ground motion for this earthquake. We have estimated the soil effects using the horizontal-to-vertical (H/V) ratio. Furthermore, high-frequency records are simulated using a modified semi-empirical technique (MSET) by including estimated site effects. This modification will provide more reliable and precise simulated strong motion records. In the present study, strong ground motions are simulated at nine seismic stations in the epicentral range of 40–99 km. These stations were selected based on their recorded data quality. To validate the technique, we have compared the synthetic records with the observed records in terms of root mean square error (RMSE). This comparison includes time records, pseudo-acceleration spectra, mean period and predominant period. This comparison shows MSET has successfully simulated the 1999 Izmit earthquake. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Strong-Motion Simulation of the 1988 Indo-Burma and Scenario Earthquakes in NE India by Integrating Site Effects in a Semi-Empirical Technique
(Birkhauser, 2021) Sonia Devi; Sandeep; Parveen Kumar; Monika
This study focuses on the validation and applicability of a recently modified semi-empirical technique (MSET) to integrate site effects. The improvement of MSET by considering site effects has been verified by the data of the 1988 Indo-Burma earthquake (Mw 7.2), which happened in the North Eastern Region (NER) in India. This technique is also used to model a future scenario earthquake (Mw 8.2) in the NER. The required site effects are estimated using Nakamura’s horizontal-to-vertical (H/V) ratio technique for 89 waveform records. The obtained site effects are further used to modify an existing semi-empirical technique. To validate this modification, the strong-motion records of the 1988 Indo-Burma earthquake are simulated for bedrock and surface conditions. Afterwards, the root mean square error (RMSE) of these records is compared with surface records obtained by 14 seismic stations. The records simulated at the surface are well validated well with observed ones as compared to the records simulated at bedrock and hence confirm the reliability of the MSET. The improved performance of the MSET after incorporation of site effects validates the approach of the present work and will prove to be significant for simulation of earthquake surface conditions in any region. Further, this improved MSET is used to simulate strong-motion records of a future scenario earthquake (Mw 8.2) with the same epicentral location. The iso-acceleration maps are prepared from simulated records for both cases (Mw 7.2 and 8.2), which provide peak ground acceleration (PGA) values of more than 500 and 1000, respectively, for near-field regions. The obtained results are of significant interest for seismic hazard assessment of NE India. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.