25. A confined aquifer with a uniform saturated thickness of 10 m has hydraulic conductivity of $10^{-2}$ cm/s. Considering a steady flow, the transmissivity of the aquifer in m2/day is _________________ (rounded off to one decimal place).   Solution:   Thickness =10 m Hydraulic conductivity of $10^{-2}$ cm/s   convert hydraulic conductivity units cm/s into m/day               = $10^{-2}*10^{-2} m/s$              = $10^{-4} m/s$   1day =86400 sec           =$10^{-4}*86400 m ..read more

1. The hydraulic conductivity measure of how easily water moves through the porous media. It depends on the permeability of the material, the degree of saturation, and the density and viscosity of the fluid. According to Darcy’s law, the specific discharge can be defined as volume flux per unit area   $\frac{Q}{A}=K \frac{dh}{dl}$------------------(1)   Q- Discharge (m3/s)   dh / dl – Hydraulic head gradient    K – Hydraulic conductivity (m/s)   A- cross-sectional area (m2)   The Hydraulic gradient is the change in total head divided the distance over which t ..read more

17. A cylindrical sample of granite (diameter = 54.7 mm; length = 137 mm) shows a linear relationship between axial stress and axial strain under uniaxial compression up to the peak stress level at which the specimen fails. If the uniaxial compressive strength of this sample is 200 MPa and the axial strain corresponding to this peak stress is 0.005, the Young’s modulus of the sample in GPa is _______ (in integer).   Solution: Given that the Axial stress= 200 Mega Pascal=200*106 Pascal                  ..read more

 18. The given figure shows the ray path of a P–wave propagating through the Earth. Choose the CORRECT P–phase corresponding to the ray path.   A) PcP B) PKP C) PPP D) PmP Answer: B For more information please check below post: https://gpsurya.blogspot.com/2018/05/csir-net-2017-june-94.html References:  1. Fundamentals of Geophysics by William Lowrie ..read more

17. The heat production $(Q_r)$ of a granitic rock due to the decay of the radioactive elements U, Th, and K having concentrations Cu, CTh, and CK, respectively, is given by the expression $Q_r=\alpha C_u+\beta C_{Th} +\gamma C_K $ Which one of the following correctly represents the relation between the magnitude of coefficients a, b, g (in mWkg^−1)? A)$\alpha >\beta >\gamma$ B)$\alpha < \beta> \gamma$ C)$\alpha > \beta < \gamma$ D)$\alpha < \beta < \gamma$ Solution: The amount of heat generated per second by these elements (in $mWkg^−1$ ) are: natural uranium, 95 ..read more

  1. Gravitational acceleration (gravity) is commonly expressed in units of milligals (mGal). $1 Gal=1cm/s^2=0.01 m/s^2$ $1mGal=10^{-3}Gal=10^{-3} cm/s^2=10^{-5} m/s^2$ References:  1. Fundamentals of Geophysics by William Lowrie. 2. Whole Earth Geophysics by J. Lilliwe ..read more

 96. A Thick Sedimentary formation, in Which the seismic wave Velocity V Increases with depth Z from $V_0$ at the surface to $V_1$ at the bottom according to the relation $V_1=V_0e^{\lambda z}$ . the Two way reflection travel time at a point closest to the short point is ….. (Special Thanks to Pawan Singh) (Thanks to Ashok, AKNU) Solution: Given that $V=V_0e^{\lambda z}$ At  Z  =  0          $V = V_0$     ( surface ) At   Z =  Z     &nb ..read more

 24.  A seismic reflection survey is carried out over a 1500 m thick horizontal layer with a P-wave velocity of 2000 m/s. The travel time of a reflected wave at a surface detector placed 1000m from a surface source is _______ milliseconds. (Thanks to Pragnath, AU) Solution: Given that $V_{p}=2000 m/s=2 Km/s~$;     d( depth)=1500 m=1.5 Km;       x(offset distance)=1000m=1 Km. $T^{2}=\frac{X^{2}}{V^{2}}+(\frac{2D}{V})^2$ $T^{2}=\frac{1^{2}}{2^{2}}+(\frac{2(1.5)}{2})^2$ $T^{2}=\frac{1}{4}+(\frac{3}{4})^2$ $T^{2}=0.25+(1.5)^2$ $T^{2}=0.25 ..read more

 22. Skin Depth in homogeneous media of resistivity $\rho_{1}$ and $\rho_{2}$ are 100 m and 200 m respectively, at 1000Hz frequency. The ratio $\frac{\rho_{1}}{\rho_{2}}$ will be __________.  (Thanks to Pragnath, AU) Solution: Skin depth formula  $D = 503.8 * \sqrt{(\frac{\rho}{f})}$ Given that,  $D_{1}= 100m~,D_{2}= 200 m$;         $f=1000~Hz$ $\frac{D_{1} = 503.8 * \sqrt{(\frac{\rho_{1}}{f})}}{D_{2} = 503.8 * \sqrt{(\frac{\rho_{2}}{f})}}$ $\frac{100}{200}=\frac{503.8 * \sqrt{(\frac{\rho_{1}}{1000})}}{ 503.8 * \sqrt{(\frac{\rho_{2}}{1000 ..read more

 21. A Mid-oceanic-Ridge has symmetric magnetic anomalies about the ridge axis as shown below. Using the information given in the figure, the average relative velocity between the Plates A and b is calculated to be ________ cm/year. (Thanks to Pragnath, AU) Solution: We know that $Velocity=\frac{Distance}{Time}$ Given that,  Distance=50 Km= 5*10^6 cm Time= 1 million year= 10^6 years $Velocity=\frac{5*10^6}{10^6}$ Relative velocity of the ridge is  =10 cm/year   If you fixed one side of the ridge then, the Absolute Velocity is= 5cm/year ..read more