Simulation of strong ground motion for a potential Mw7.3 earthquake in Kopili fault zone,northeast India

Natural Hazards - The occurrence of major natural disasters in recent years has impacted large cities worldwide and boosted the need of assessing urban resilience. As a key factor of resilience,...     

Effect of electron temperature on small-amplitude electron acoustic solitary waves in non-planar geometry

Effects of electron temperature on the propagation of electron acoustic solitary waves in plasma with stationary ions, cold and superthermal hot electrons is investigated in non-planar geometry employing reductive perturbation method. Modified Korteweg–de Vries equation is derived in the small amplitude approximation limit. The analytical and numerical calculations of the KdV equation reveal that the phase velocity of the electron acoustic waves increases as one goes from planar to non planar geometry. It is shown that the electron temperature ratio changes the width and amplitude of the solitary waves and when electron temperature is not taken into account,our results completely agree with the results of Javidan & Pakzad (2012). It is found that at small values of \(\tau \), solitary wave structures behave differently in cylindrical (\(\text {m} = 1\)), spherical (\(\text {m} = 2\)) and planar geometry (\(\text {m} = 0\)) but looks similar at large values of \(\tau \). These results may be useful to understand the solitary wave characteristics in laboratory and space environments where the plasma have multiple temperature electrons.     

Seismotectonic study of Kishtwar region of Jammu Province using local broadband seismic data

Two moderate earthquakes of Mw 5.7 on the first of May and Mw 5.2 on the second of August occurred in the Kishtwar region in the year 2013. Our broadband seismic observatories located in the region recorded these events and the aftershocks. We analyzed these data to understand the seismotectonics of this region. Most of the events were located between 33.03° to 33.29° N latitude and 75.40° to 76.07° E longitude. Focal depths of these shallow earthquakes range from 7 to 12 km and are confined between Panjal Thrust (PT) and Kishtwar Window (KW). Spectral analysis of these events reveals that stress drop, source radius, corner frequency, and moment magnitude varied between 3.3 and 70.1 bars, 0.121 and 3.55 km, 0.397 and 6.06 Hz, and Mw 2.2 and Mw 5.7, respectively. The low stress drop of small-magnitude earthquakes reveals the brittle nature of the upper crust which is coincident with the field observations. The variation of stress drop with magnitude shows positive correlation whereas no such relation was observed between stress drop and depth of focus. The b value calculated (0.83) for the area reveals high stress accumulation within the incompetent rock zones in the area.     

Intensity distribution of M 4.9 Haryana–Delhi border earthquake

In this study, we have prepared an intensity map based on macroseismic survey and all the available information from print and electronic media of damage and other effects due to March 05, 2012, M 4.9 Bahadurgarh (Haryana–Delhi border) earthquake and interpreted them to obtain modified Mercalli intensities (MMI) at over 62 locations surrounding the Haryana and Delhi. We have cross-checked the damage information from print and electronic media in the field at 25 sites within 110 km surrounding the epicenter for validation. Based on the questionnaire which is used in macroseismic survey and personal judgment, intensities were assigned accordingly as per physical survey at 25 sites and for rest based on media reporting. A maximum intensity of VI was assigned to this seismic event. Isoseismals of V and VI have been fully covered in the field observations. Beside this, some of the points have also been covered for isoseismal IV and isoseismal III and rest are based on media report only. The intensity map reveals several interesting features. Elliptically elongated shape of intensity map shows that most of the slightly damaged areas are concentrated toward the northwestern side of the epicenter having intensity V which may be due to directivity or site effects. A regression relation has also been derived between intensity and epicentral distance. The derived attenuation relation will be useful for assessing damage of a potential future earthquake (earthquake scenario–based planning purposes) for the Delhi NCR region.     

Photocatalytic degradation of azo dye Orange II in aqueous solutions using copper-impregnated titania

During dyeing process, industries consume large quantity of water and subsequently produce large volume of wastewater. This wastewater is rich in color and contains different dyes. Orange II is one of them. In this article, metal-impregnated TiO₂ P-25 catalyst was used to enhance the photocatalytic degradation of Orange II dye. Photodegradation percentage was followed spectrophotometrically by the measurements of absorbance at λ _max = 483 nm. The effect of copper-impregnated TiO₂ P-25 photocatalyst for the degradation of Orange II has been investigated in terms of percentage removal of color, chemical oxygen demand (COD) and total organic carbon (TOC). As such 98 % color removal efficiency, 97 % percentage removal of COD and 89 % percentage removal of TOC was achieved with TiO₂ P-25/Cu catalysts under typical conditions. Copper-impregnated TiO₂ P-25 photocatalyst showed comparatively higher activity than UV/H₂O₂ homogeneous photodegradation. The relative electrical energy consumption for photocatalytic degradation was considerably lower with TiO₂ P-25/Cu photocatalyst than that with homogeneous photodegradation. Transmission electron microscopic analysis was used for catalyst characterization.     

Science and technology based earthquake risk reduction strategies: The Indian scenario

Science and Technology (S & T) interventions are considered to be very important in any effort related to earthquake risk reduction. Their three main components are: earthquake forecast, assessment of earthquake hazard, and education and awareness. In India, although the efforts towards earthquake forecast were initiated about two decades ago, systematic studies started recently with the launch of a National Program on Earthquake Precursors. The quantification of seismic hazard, which is imperative in the present scenario, started in India with the establishment of first seismic observatory in 1898 and since then a substantial progress has been made in this direction. A dedicated education and awareness program was initiated about 10 years ago to provide earthquake education and create awareness amongst the students and society at large. The paper highlights significant S & T efforts made in India towards reduction of risk due to future large earthquakes.     

Generation and Validation of two Day Composite Wind Fields from Oceansat-2 Scatterometer

The Oceansat-2 scatterometer (OSCAT) of the Indian Space Research Organization (ISRO), provides surface wind speed and direction with a spatial resolution of 50 km × 50 km. With a revisit time of 2 days it had provided ocean surface wind vectors over the global oceans. In the present work, an attempt has been made to generate two day composite of OSCAT wind vectors using Data-Interpolating Variational Analysis (DIVA) and compare them with daily composite winds to check how better is the two day composites in comparison to daily composites. The daily and two days composite wind vectors of zonal (U) and meridional (V) components have been validated with wind measurements from in situ buoys and Advanced Scatterometer (ASCAT) for the year 2012 over the tropical Indian Ocean region. The statistical comparison with the in situ measurements and ASCAT has shown that the two-day OSCAT wind composites are slightly better than the daily composite winds. The improvement in the statistics can be attributed to the use of ascending and descending passes pertaining to two days which results in fewer gaps between passes, thereby reducing the interpolation errors.     

Fault rupture directivity of large earthquakes in Himalaya

The paper examines the predominant fault rupture directivity during large earthquakes in different sectors of the Himalaya which influences strong ground motion and damage scenario. The nature of the faulting of earthquakes vis-à-vis their rupture directivity has been discussed. It is found that the rupture directivity near the Indo-Eurasian plate boundary varies from place to place i.e. either along the strike direction of the faults or at right angles to it. The secondary meizoseismal areas as observed for 1505 Dharchula, 1803 Uttarakhand, 1905 Kangra earthquakes in the Himalaya and 2001 Bhuj earthquake in stable continental region suggest that they are a fairly good indicator of predominant rupture directivity since the latter accentuates the site response up to a longer distance. The resulting larger ground motions, therefore, need to be incorporated in the design of engineering structures by suitable modifications in the BIS code.