List of top Geophysics Questions on Seismology

Consider a seismic source located at the Earth's surface. A vertical well is located at a distance of 1 km away from the seismic source, and a geophone is suspended inside the well at a depth of 800 m, as shown in the figure below.
The travel time of the primary reflected wave from a horizontal reflector located at a depth of 2 km is ___________ s (rounded off to three decimal places).
The maximum strain for the plane wave at \(t=0\), having a wavelength of 16 km and unit amplitude, travelling along the X-direction, as shown in the figure, is _______ (rounded off to three decimal places).
The given figure shows the geometry of a seismic ray path inside the Earth, with the P-wave velocities of 10 km/s, 11 km/s and 12 km/s corresponding to the layers L1, L2 and L3, respectively. If the angle of incidence (\(\theta\)) at the L1-L2 boundary is \(40^\circ\), then what is the angle of refraction at the L2-L3 boundary? (answer in nearest integer)

(In the figure, \(r_1 = 3100\) km is the radius, measured from the Earth's centre O, of the L1-L2 boundary, and \(r_2 = 3000\) km is the radius of the L2-L3 boundary.)
If a seismic wave is travelling along the radial direction, then which of the following statements is/are CORRECT for Rayleigh (R) and Love (L) waves?
A P-wave of frequency 20 Hz is travelling through a non-dispersive medium with a velocity of 5 km/s. The amplitude retained at a distance of 10 km from source is _____________ % (rounded off to one decimal place). (Use quality factor, \(Q = 80\))
Given the Rayleigh wave velocity \(V_r\), shear wave velocity \(V_s\) and the P-wave velocity \(V_p\), which of the following relationships is/are CORRECT?
If \(\tau\) and \(p\) denote intercept time and slowness, respectively, in the \(\tau-p\) diagram, then which one of the following is CORRECT for a P-wave propagating inside the Earth?
If \(A_b\) and \(A_s\) denote the amplitudes of the body and surface waves, respectively, at a distance, \(r\), from the source, then the relation between them is given by
In which one of the following layers inside the Earth, the velocity of the P-wave exceeds 13 km/s?