Mahesh Prasad Parija | Virginia Tech (original) (raw)

Papers by Mahesh Prasad Parija

Scientific Reports

The crustal seismic attenuation or the Q structure is studied by using the Fourier spectra of Lg-... more The crustal seismic attenuation or the Q structure is studied by using the Fourier spectra of Lg-wave along the Tanakpur- Dharchula- Dharma transect in the Kumaon Himalaya. The 1 Hz Lg Q (Q0) values are computed between different pairs of two stations and the observed values are later utilized to calculate the lateral variation in the Q0 values by following a back projection algorithm. This computation of Q0 values utilizes five regional distance earthquakes having moment magnitude (Mw) ≥ 4.0, which lie along the great circle path of the transect. Three of the five earthquakes occurred in the Tibetan plateau and the and the others occurred to the southwest on the Indian shield and are well recorded at all the 32 broadband seismographs operated between September 2018 and March 2022. The estimate Qo values range from 63 ± 2 and 203 ± 25, with the lowest value in the Lesser Himalaya and the highest across part of the Indo Gangetic Plain and Siwalik Himalaya. The Q0 model has low values...

AGU Fall Meeting Abstracts, Dec 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2019

Tectonics, 2021

Vegetable crops quality lose commences right along the rout of harvesting, transportation, storag... more Vegetable crops quality lose commences right along the rout of harvesting, transportation, storage, and delivery to consumers. A pairwise comparison of the criteria with respect to the goal was performed based on the food technology experts' suggestions. Considering the economic feasibility and personal skill, fermentation (29.0%) taken greatest weight followed by hot water treatment technique (27.3%). Likewise, those techniques for tomato preservation in different ways like solar dryer (SD), cold house storage (CHS), and modi ed atmosphere packaging (MAP) account 20.7%, 15.6% and 7.3% respectively. This research nding could bene t small to large holding farmers, retailers and investors intended to work on tomato processing sector for supporting the sustainable development intent.

Lithosphere, 2020

This study investigates the upper mantle deformation pattern beneath the Indo-Eurasia collision z... more This study investigates the upper mantle deformation pattern beneath the Indo-Eurasia collision zone utilizing the core-refracted (S(K)KS) phases from 167 earthquakes recorded by 20 broadband seismic stations deployed in the Western Himalaya. The 76 new shear wave splitting measurements reveal that the fast polarization azimuths (FPAs) are mainly oriented in the ENE-WSW direction, with the delay times varying between 0.2 and 1.7 s. The FPAs at most of the stations tend to be orthogonal to the major geological boundaries in the Western Himalaya. The average trend of the FPAs at each station indicates that the seismic anisotropy is primarily caused due to strain-induced deformation in the top ~200 km of the upper mantle as a result of the ongoing Indo-Eurasian collision. A contribution from the mantle flow in the direction of the Indian plate motion is possible. The mantle strain revealed in the present study may be due to a combination of basal shear resulting from plate motion and d...

Journal of the Geological Society of India, 2022

The September 18, 2011 earthquake of M 6.9 has been critically examined and found to be associate... more The September 18, 2011 earthquake of M 6.9 has been critically examined and found to be associated with episodes of precursory swarms, quiescence, mainshock and aftershocks. This earthquake was clearly preceded by precursory swarm activity for almost one year followed by quiescence for one year. The precursory swarm and quiescence period consists of four earthquake swarms and one foreshock event of magnitude (mb ≥ 4.5) in the epicenter preparatory zone of the 2011 Sikkim earthquake. The 2011 Sikkim earthquake recorded about five aftershocks of magnitude (mb) ≥ 4.5 between 2011 and 2014 for the same region. This study shows that the 2011 Sikkim earthquake followed the same sequence of activities as observed for other major earthquakes in the northeast Himalaya.

Lithosphere, 2022

The optimum 1D velocity model is calculated for the Kinnaur sector of the NW Himalaya utilizing t... more The optimum 1D velocity model is calculated for the Kinnaur sector of the NW Himalaya utilizing the arrival time information of the local earthquakes (137 no.) recorded with 12 broadband seismic network within the azimuthal gap of ≤180°. This optimum 1D velocity model is a five-layer model and ranges from the surface to 90 km in the shallow mantle. P velocity varies from 5.5 km/s to 8.6 km/s in the crust and upper mantle, and S-wave velocity varies between 3.2 km/s and 4.9 km/s for the same range. When we relocated the earthquakes with the Joint Hypocenter Determination program incorporating the optimum 1D velocity model, it resulted in a lower RMS residual error of 0.23 s for the hypocenter locations compared to initial hypo71 locations. A total of 1274 P and 1272 S arrival times were utilized to compute station delays. We observed positive variations in P-station delays from -0.19 s below the PULG station to 0.11 s below the SRHN station. Similarly, for S-station delays, we observ...

Journal of Asian Earth Sciences, 2016

Digital seismogram data of 82 earthquakes from the Northwestern Himalayan (India) region recorded... more Digital seismogram data of 82 earthquakes from the Northwestern Himalayan (India) region recorded at different stations during 2004–2006 were analyzed to study the seismic coda wave attenuation characteristics in this region. We used 132 seismic observations from local earthquakes with a hypocentral distance Q C using the single isotropic scattering model. These earthquakes were recorded at 20 temporary seismic stations installed in the Northwestern Himalayas (India) by the Wadia institute of Himalayan Geology, Dehradun. The Q C values were estimated at 10 central frequencies: 1.5, 3, 5, 7, 9, 12, 16, 20, 24, and 28 Hz using starting lapse-times of 10, 20, 30, 40, 50, and 60 s and coda window-lengths of 10, 20, 30, 40, and 50 s. The Q C fits the frequency dependent power-law, Q C = Q 0 f n . For a 10 s lapse time with a 10-s coda window length Q C = 47.42 f 1.012 and for a 50 s lapse time with a 50 s coda window length, Q C = 204.1 f 0.934 . Q 0 ( Q C at 1 Hz) varied from ∼47 for a ...

We calculated the static stress changes from the moderate Mb=5.8 earthquake that shook Uttarakhan... more We calculated the static stress changes from the moderate Mb=5.8 earthquake that shook Uttarakhand, India on February 6, 2017. The Coulomb stress change map on target fault planes oriented by assuming a regional compressional stress regime with the greatest principal stress directed orthogonally to the mainshock strike. Calculation sensitivity was tested by varying assumed stress orientations, target-fault friction, and frictional coefficient. The results signify that there is depth dependency of coulomb stress in the region as the stress perturbation can vary depending on the depth of computation for the study region. Also, for varying frictional coefficient, coulomb static stress computed is seemed to be independent of it in the study area for the studied recent 2017 Rudraprayag earthquake. Coulomb stress calculated over the MHT detachment suggests stress shadow over some parts of the Vaikrita Thrust (VT) and substantial-high stress is observed over the entire Himalayan detachment.

Springer Geophysics

A competent interpretation technique to estimate the model parameters such as amplitude coefficie... more A competent interpretation technique to estimate the model parameters such as amplitude coefficient (k), exact origin of causative source (x0) depth (z0) and the shape factor (q) from the total gradient computed from the horizontal and vertical derivatives of gravity and magnetic data has been presented. Global optimization of the analytic signal or the total gradient of potential field data from single and multiple sources with different idealized structures was carried out using Very Fast Simulated Annealing (VFSA) technique. The inversion of the data shows that the present method can accurately determine all model parameter. The parameters estimated specifically the depth of the buried ore bodies were in respectable agreement with the actual model parameters. Delineated histogram, cross-plots and convergence suggest that the interpretations are within the uncertainty limits. The method adopted in this study is as consistent as the others such as PSO, ACO and DE. The method has been effectively applied in noise free and noise corrupted data along with two field data from Quebec, Canada (Gravity data—Mobrun Massive Sulphide Body, Noranda, and Magnetic data—Barraute, North-West) with the presence of sulfide bodies buried at different depths and two from Turkey (Kesikkopru and Marmara anomaly) related to iron ore deposit and deep seated magnetic deposit.

Lithosphere

Journal of Seismology, Jan 5, 1997

Approximately one thousand microearthquakes with body-wave magnitude m b have been located in nor... more Approximately one thousand microearthquakes with body-wave magnitude m b have been located in northern Venezuela and the southern Caribbean region (9-12 N; 64-70 W) since the installation in 1980 of the Venezuelan Seismological Array, together with forty events of m b 4, one of them with surface-wave magnitude M s 6. Focal depths are in the range of 0 to 15 km. This geologically complex region is part of the boundary between the Caribbean and the South American Plates. Epicentral locations indicate that this E-W oriented portion of the boundary is formed by two 400 km long subparallel fault zones: San Sebastián fault zone (SSF), 20 km north of Caracas along the coast; and La Victoria fault zone (LVF), 25 km south of the city. They are clearly delineated by the microseismicity. New composite focal mechanism solutions (CFMS) along these faults show right-lateral strike-slip (RLSS) motion on nearly E-W oriented fault planes. NW-striking subsidiary active faults occur in the region and intercept the two main E-W fault zones. These interceptions show high levels of microearthquake activity and seismic moment release when compared to other portions of both, the main and subsidiary faults. New CFMS at those fault crossing sites show NW-striking RLSS motion and normal faulting, in an en-echelon-like structural behavior. Geological data and quantitative comparisons with other transcurrent plate boundaries in the world suggest that the rate of plate motion in this area is on the order of 20 mm/y. Several moderate and large shocks have occurred along the SSF and LVF since 1640, including an M s 7:6 event in 1900 on SSF. Although the region may be relatively far from a repeat of this earthquake, seismicity data indicate that strong shocks could take place along segments of the seismically active faults identified in this study.

Annals of Geophysics

An efficient approach to estimate model parameters from total gradient of gravity and magnetic da... more An efficient approach to estimate model parameters from total gradient of gravity and magnetic data based on Very Fast simulated Annealing (VFSA) is presented. This is the first time VFSA has been applied in interpreting total gradient of potential field data with a new formulation estimation caused due to isolated causative sources embedded in the subsurface. The model parameters interpreted here are the amplitude coefficient (k), exact origin of causative source (x 0) depth (z 0) and the shape factors (q). The results of VFSA optimization show that it can uniquely determine all the model parameters when shape factor is controlled to its actual value. The model parameters estimated by the present method, mostly the shape and depth of the buried structures were found to be in excellent agreement with the actual parameters. The method has also the proficiency of evading highly noisy data points and improves the interpretation results. Study of histogram and cross-plot analysis also suggests the interpretation within the estimated uncertainty. Inversion of noise-free and noisy synthetic data for single structures as well as field data demonstrates the efficacy of the approach. The technique is warily and effectively applied to real data examples (Leona Anomaly, Senegal for gravity, Pima copper deposit, USA and Matheson area, Northern Ontario, Canada for magnetic/aeromagnetic data) with the presence of ore bodies. The present method can be extremely applicable for mineral exploration or ore bodies of dyke-like structure embedded in the shallow and deeper subsurface. The computation time for the whole process is very small.

Journal of Seismology, 2015