List of top Geology and Geophysics Questions

In radiometric surveys, potassium in subsurface rocks will show a $\gamma$-ray peak in which one of the following MeV energy channels?
The given beach-ball figure denotes the focal mechanism corresponding to which one of the following faults? \includegraphics[width=0.5\linewidth]{16.png}
At present, which one of the following planets does NOT have a magnetic field of internal origin produced by an active dynamo?
Which one of the following geophysical methods is suitable for the identification of seepage of water from dams?
Which one among the following events recorded in a land seismic reflection survey using vertical component geophones has the highest apparent slowness?
A GPR pulse is propagated into a non-magnetic medium comprising a single layer underlain by a half space. If the dielectric constants for the top layer and the half-space are \(\varepsilon_1\) and \(\varepsilon_2\), respectively, the reflection coefficient at normal incidence is
The given figure shows the self-potential anomaly observed over a two-dimensional thin sheet-type ore body whose strike is perpendicular to the plane of the paper. Which one of the following directions of polarization of the ore body leads to the given anomaly? \includegraphics[width=0.5\linewidth]{11.png}
With increasing depth in the Earth, the P-wave velocity shows a significant decrease across which one of the following boundaries?
A current of 2 A passes through a cylindrical rod with uniform cross-sectional area of 4 m$^2$ and resistivity of 100 $\Omega$-m. The magnitude of the electric field (E) measured along the length of the rod in V/m is _________ (in integer).
The fold of a 2D seismic survey is defined as the maximum number of traces in which one of the following gathers?
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. \includegraphics[width=0.5\linewidth]{6.png}
Match the geophysical methods in Group–I with their associated physical properties in Group–II. \begin{tabular}{ll} Group–I & Group–II
P. Magnetic & 1. Chargeability
Q. Gravity & 2. Electrical conductivity
R. Magnetotelluric & 3. Susceptibility
S. Induced Polarization & 4. Density
\end{tabular}
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).
The given figure depicts an array used in DC resistivity surveys, where the current electrodes are denoted by C1 and C2, and potential electrodes by P1 and P2. If all the electrodes are equally spaced, then the given array corresponds to which one of the following configurations? \includegraphics[width=0.5\linewidth]{5.png}
Which one of the following logging tools is used to measure the diameter of a borehole?
The Earth's magnetic field originates from convection in which one of the following layers?
The mole fraction of jadeite in the pyroxene of composition (Ca$_{0.667}$Na$_{0.333}$Fe$^{2+}_{0.12}$Fe$^{3+}_{0.125}$Mg$_{0.546}$Al$_{0.208}$)Si$_2$O$_6$ is .................. [round off to 3 decimal places]
A cylindrical soil sample of 10 cm diameter is tested in a constant-head permeameter. A volume of 250 cm$^3$ of water is collected in 5 minutes when the constant-head difference between tapping points 15 cm apart is 5 cm. Considering Darcy flow, the absolute value of coefficient of permeability in cm/s is .............. ($\pi = 3.14$) [round off to 3 decimal places]
The amount of Fe in a sample of 25 g of pyrrhotite (FeS) is $\underline{\hspace{1cm}}$ g. (Atomic wt. of Fe = 55.85 and S = 32.06) [round off to 2 decimal places]
A vertical aerial photograph is obtained over flat terrain with a 30 cm focal-length camera lens from an altitude of 18288 m. If the width of a dolerite dyke on this vertical photograph is 2 mm, its actual width on the terrain is $\underline{\hspace{1cm}}$ m. [round off to 2 decimal places]
The decay constant of a radioactive isotope is \(1.21\times 10^{-4}\ \text{year}^{-1}\). The half-life of the isotope is $\underline{\hspace{3cm}}$ years. [round off to nearest integer]
Shallow-focus earthquakes with tensional focal mechanism are characteristic of:
Which of the following is NOT an essential property of a mineral?
For the given figure, considering Pratt's model of isostatic compensation at the crust–mantle boundary, the crustal density ($\rho_1$) that explains 1.5 km deep lake is $\underline{\hspace{1cm}}$ kg/m$^3$. (Consider density of water $\rho_w = 1000$ kg/m$^3$) [round off to 2 decimal places] \begin{center} \includegraphics[width=0.5\textwidth]{05.jpeg} \end{center}
Wenner DC resistivity survey. The operator forgot to cancel self-potential (SP) between potential electrodes before injecting current. With equal current magnitude: measured \(\Delta V_1=+158\ \text{mV}\) for current \(C1\rightarrow C2\) and \(\Delta V_2=-214\ \text{mV}\) for reversed current \(C2\rightarrow C1\). Determine the SP (in mV, integer) that existed between potential electrodes before current injection.